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Utilize HTML5 DataList And JQuery Ajax To Create Autocomplete In ASP.NET MVC

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In data entry forms involving textboxes with predictable values one can use autocomplete to assist user pick an existing value. HTML5 introduces <datalist> element that can come handy while implementing autocomplete. The <datalist> element holds a list of options and can be attached with a textbox using list attribute. By adding a bit of jQuery Ajax you can dynamically populate the options in a <datalist>. This article shows you how to do just that.

HTML5 <datalist> element is used as shown in the following markup.

<input type="text" list="datalist1" />

<datalist id="datalist1">
  <option value="US" label="United States" />
  <option value="UK" label="United Kingdom" />
  <option value="IN" label="India" />
</datalist>

At runtime the above markup shows an autocomplete as shown below:

image

Once you select an option from the list, the textbox is filled with the value. The <datalist> and its <option> elements are statically placed in the above markup. If you wish to dynamically populate the <datalist> based on the value entered in the textbox, you need to make an Ajax call to the server and fetch the required data.

Consider the following HTML markup that has a textbox and an empty <datalist>.

<h1>Autocomplete Example</h1>
<input id="companyName" list="companyList" />
<datalist id="companyList"></datalist>

To dynamically populate the <datalist> you can add the following jQuery code:

$(document).ready(function () {
    $("#companyName").on("input", function () {
        var options = {};
        options.url = "/home/getcompanylist";
        options.type = "GET";
        options.data = { "criteria": $("#companyName").val() };
        options.dataType = "json";
        options.success = function (data) {
            $("#companyList").empty();
            for(var i=0;i<data.length;i++)
            {
                $("#companyList").append("<option value='" + 
                data[i].CompanyName + "'></option>");
            }
        };
        $.ajax(options);
    });

});

The above jQuery code wires the input event handler for the companyName textbox. The code makes an Ajax call to an MVC action method - GetCompanyList(). This action method returns a list of CompanyName values from Customers table of the Northwind database. While making the Ajax call you pass the textbox value to the action method as the search criteria. The success function receives an array of JavaScript objects. Each object has a single property - CompanyName - that is then filled in <option> elements of companyList.

The GetCompanyList() action method finds all the company names containing the entered text. The GetCompanyList() action is shown below:

public JsonResult GetCompanyList(string criteria)
{
    NorthwindEntities db = new NorthwindEntities();
    var query = (from c in db.Customers
                    where c.CompanyName.Contains(criteria)
                    orderby c.CompanyName ascending
                    select new { c.CompanyName }).Distinct();
    return Json(query.ToList(),JsonRequestBehavior.AllowGet);
}

Notice that GetCompanyList() action returns JsonResult using Json() method. Also notice that JsonRequestBehavior is set to AllowGet so that GET requests can call this method.

That's it! You can now run the application and test whether it dynamically displays the autocomplete. The following figure shows a sample run.

image

posted Nov 4, 2016 by Shivaranjini

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Related Articles

Select All And Delete Using ASP.NET MVC And JQuery Ajax

Sometimes you need to select records for certain action using checkboxes. For example, you may select records for deleting and then delete them from the database. Consider the following screen shot that shows such an example in action.

image

As you can see there are two ways to select records for deletion:

  • You select checkboxes for rows to be deleted individually.
  • You can check the checkbox placed in the header row to select all the rows. This checkbox toggles the checked state of the other checkboxes.

Once selected you can click on the Delete Selected Customers button to actually delete the records.

Implementing such a functionality is straightforward using ASP.NET MVC, jQuery and Ajax. Let's see how.

As an example we will use Customers table of the Northwind database for this example. You will need to create a model class for the Customers table using EF code first. The Customer class is shown below:

public partial class Customer
{
    [StringLength(5)]
    public string CustomerID { get; set; }

    [Required]
    [StringLength(40)]
    public string CompanyName { get; set; }

    [StringLength(30)]
    public string ContactName { get; set; }

    [StringLength(30)]
    public string ContactTitle { get; set; }

    [StringLength(60)]
    public string Address { get; set; }

    [StringLength(15)]
    public string City { get; set; }

    [StringLength(15)]
    public string Region { get; set; }

    [StringLength(10)]
    public string PostalCode { get; set; }

    [StringLength(15)]
    public string Country { get; set; }

    [StringLength(24)]
    public string Phone { get; set; }

    [StringLength(24)]
    public string Fax { get; set; }
}

The NorthwindDbContext - the DbContext of our model - is shown below:

public partial class NorthwindDbContext : DbContext
{
    public NorthwindDbContext()
        : base("name=NorthwindDbContext")
    {
    }

    public virtual DbSet<Customer> Customers { get; set; }

    protected override void OnModelCreating
                (DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Customer>()
            .Property(e => e.CustomerID)
            .IsFixedLength();
    }
}

Notice that the NorthwindDbContext assumes that the database connection string is stored in web.config with a name of NorthwindDbContext.

Now add HomeController and write Index() and Delete() actions as shown below:

public ActionResult Index()
{
    using (NorthwindDbContext db = 
                  new NorthwindDbContext())
    {
        var query = from c in db.Customers
                    select c;
        return View(query.ToList());
    }
}

public ActionResult Delete(string[] customerIDs)
{
    using (NorthwindDbContext db = 
                        ew NorthwindDbContext())
    {
        foreach (string customerID in customerIDs)
        {
            Customer obj = db.Customers.Find(customerID);
            db.Customers.Remove(obj);
        }
        db.SaveChanges();
        return Json("All the customers 
                     deleted successfully!");
    }
}

The code from the Index() action simply picks all the customers from the Customers table and passes them to the Index view for display.

The Delete() action takes a single parameter - array of CustomerIDs to be deleted. The Delete() action will be called through client side jQuery code and while calling the array will be passed to it. The Delete() action simply iterates through the customerIDs array and one-by-one deletes the customers from the database. Finally, a success message is sent back to the caller in JSON format.

Now add Index view and also add a <script> reference to the jQuery library. Then add the following markup in the Index view.

@model List<SelectAllDeleteDemo.Models.Customer>
...
...
<body>
    <h1>List of Customers</h1>
    <input type="button" id="delete" 
         value="Delete Selected Customers" />
    <br /><br />
    <table border="1" cellpadding="10">
        <tr>
            <th><input type="checkbox" id="checkAll"/></th>
            <th>CustomerID</th>
            <th>CompanyName</th>
            <th>Country</th>
        </tr>
        @foreach(var item in Model)
        {
            <tr>
                <td><input type="checkbox" class="checkBox" 
                     value="@item.CustomerID" /></td>
                <td>@item.CustomerID</td>
                <td>@item.CompanyName</td>
                <td>@item.Country</td>
            </tr>
        }
    </table>
</body>
...

Notice a few things about this markup:

  • The customer data - CustomerID, CompanyName and Country - is displayed in a table.
  • The header row contains a checkbox whose ID is checkAll
  • Each table row contains a checkbox whose class attribute is set to checkBox. And its value is set to the CustomerID of that row.
  • The button above the table is used to initiate the delete operation and its ID is delete.

Now add a <script> block and write the following jQuery code:

$(document).ready(function () {

    $("#checkAll").click(function () {
        $(".checkBox").prop('checked', 
            $(this).prop('checked'));
    });

    $("#delete").click(function () {
        var selectedIDs = new Array();
        $('input:checkbox.checkBox').each(function () {
            if ($(this).prop('checked')) {
                selectedIDs.push($(this).val());
            }
        });

        var options = {};
        options.url = "/home/delete";
        options.type = "POST";
        options.data = JSON.stringify(selectedIDs);
        options.contentType = "application/json";
        options.dataType = "json";
        options.success = function (msg) {
            alert(msg);
        };
        options.error = function () {
            alert("Error while deleting the records!");
        };
        $.ajax(options);

    });
});

The code wires click event handlers for the checkAll checkbox and the delete button. The click event handler of the checkAll checkbox toggles the checked state of all the checkboxes. This is done by selecting the checkboxes using the jQuery class selector. The checkboxes whose class attribute is checkBox are matched and their checked property is toggled. Notice the use of prop() method to do this.

The click event handler of the delete button declares an array variable to store the selected CustomerIDs. It then selects all the checkboxes with CSS class of checkBox. The each() method iterates through these checkboxes. If a checkbox is checked its value is pushed into the array. This way we get all the CustomerIDs into the selectedIDs array. The success callback simply displays the success message returned from the Delete() action.

Then options object is created to hold all the Ajax configuration properties. Notice that url property points to the Delete() action and data property holds the JSON version of the selectedIDs array. Finally, $.ajax() is used to make the Ajax call.

That's it! Run the application and test the functionality.

 READ MORE
Implementing Ajax Login In ASP.NET MVC

Recently during a training program one of the participant asked this question - "How to create a login page using jQuery Ajax in MVC applications?" This article is illustrates how Ajax login can be implemented using Forms authentication, Membership and jQuery $.ajax().

Implementing Ajax based login involves many of the same steps as the normal forms authentication. However, the login page doesn't send user ID and password to the server through a standard form submission. Instead, user credentials are sent to the server via an Ajax request. The credentials are then validated on the server and the result of the verification process is conveyed to the client. If the login attempt was successful, the user is taken to the secured area of the website.

Let's understand how all this works by developing a sample application. Begin by creating a new ASP.NET MVC Web Application using an empty template. To keep things simple we will add only those things to the project that are absolutely essential to the functioning of this example.

Configure a database for membership services

First of all you need to configure a database for membership services. This is done with the help of aspnet_regsql.exe tool. Open Visual Studio developer command prompt and issue the said command to open the configuration wizard. Simply follow the wizard to configure your database. For example, here I am configuring Northwind database to support membership services.

image

Configure forms authentication and membership provider

Next, open the web.config of the web application and configure the authentication scheme as shown below:

<connectionStrings>
  <add name="connstr" connectionString="data source=.\sqlexpress;
                      initial catalog=Northwind;integrated security=true"/>
</connectionStrings>

<system.web>
  <authentication mode="Forms">
    <forms loginUrl="~/account/login" defaultUrl="~/home/index"></forms>
  </authentication>
  ...
</system.web>

The <authentication> tag sets the authentication mode to Forms. The forms authentication is configured to have login page as ~/account/login and default page as ~/home/index. The <connectionStrings> section defines a database connection string for the Northwind database. This connection string is used while configuring the membership provider.

To configure the membership provider add the following markup to the web.config file:

<membership defaultProvider="p1">
  <providers>
    <add name="p1" connectionStringName="connstr" 
                   type="System.Web.Security.SqlMembershipProvider" />
  </providers>
</membership>

Create Account controller

Then add a controller to the Controllers folder - AccountController. The Account controller contains code that validates a user. The Login() and ValidateUser() action methods of the Account controller are shown below:

public ActionResult Login()
{
    return View();
}

[HttpPost]
public JsonResult ValidateUser(string userid, string password, 
                               bool rememberme)
{
    LoginStatus status = new LoginStatus();
    if (Membership.ValidateUser(userid, password))
    {
        FormsAuthentication.SetAuthCookie(userid, rememberme);
        status.Success = true;
        status.TargetURL = FormsAuthentication.
                           GetRedirectUrl(userid, rememberme);
        if (string.IsNullOrEmpty(status.TargetURL))
        {
            status.TargetURL = FormsAuthentication.DefaultUrl;
        }
        status.Message = "Login attempt successful!";
    }
    else
    {
        status.Success = false;
        status.Message = "Invalid UserID or Password!";
        status.TargetURL = FormsAuthentication.LoginUrl;
    }
    return Json(status);
}

The Login() action method simply returns the Login view. The ValidateUser() method is important to us because this method validates the user credentials and is called via Ajax. The ValidateUser() method takes three parameters - userid, password and rememberme. Inside, it calls ValidateUser() method of the Membership object to decide whether the user ID and password is correct. The ValidateUser() method also creates an instance of LoginStatus class - a POCO that is intended to store the status of the login process. The LoginStatus class looks like this:

public class LoginStatus
{
    public bool Success { get; set; }
    public string Message { get; set; }
    public string TargetURL { get; set; }
}

The LoginStatus class consists of three properties - Success, Message and TargetURL. The Success boolean property holds true if the login attempt was successful, false otherwise. The Message property holds a succcess or error message that is to be displayed to the end user. The TargetURL property holds the page URL where the user should be redirected if the login attempt was successful.

Coming back to the ValidateUser() method, if the user credentials are valid a forms authentication cookie is issued using the SetAuthCookie() method. The LoginStatus object is populated with the required information. Notice how the TargetURL is determined using GetRedirectUrl() method and DefaultUrl properties of the FormsAuthentication class.

If the login attempt was unsuccessful, LoginStatus object is populated with error information. Finally, LoginStatus object is sent back to the caller using Json() method. Remember that ValidateUser() method will be called using Ajax and hence should return data to the browser in JSON format.

Create Login view

Now add the Login view and design it as shown below:

image

The Login view consists of a textbox, a password box, a checkbox and a button. Clicking on the Login button initiates an Ajax request to the ValidateUser() method you created earlier. The jQuery code responsible for calling the ValidateUser() method is given below:

$(document).ready(function () {
    $("#login").click(function () {
        $("#message").html("Logging in...");
        var data = { "userid": $("#userid").val(), 
                     "password": $("#password").val(), 
                     "rememberme":$("#rememberme").prop("checked") };
        $.ajax({
            url: "/account/validateuser",
            type: "POST",
            data: JSON.stringify(data),
            dataType: "json",
            contentType: "application/json",
            success: function (status) {
                $("#message").html(status.Message);
                if (status.Success)
                {
                    window.location.href = status.TargetURL;
                }
            },
            error: function () {
                $("#message").html("Error while authenticating 
                                    user credentials!");
            }
        });
    });
});

Observe this code carefully. Upon clicking the login button a progress message is displayed in a message <div> element. The code then forms a JavaScript object that has three properties - userid, password and rememberme. These property names must match the parameter names of the ValidateUser() action method you created earlier. Then $.ajax() of jQuery is used to make an Ajax request to /account/validateuser. The type of the request is set to POST. The data setting contains the stringified version of the data JavaScript object you just created. The dataType and contentType properties are set to json and application/json respectively. These two properties represent the response format and the request MIME content type respectively. The success function receives a status object. This object is a JSON representation of LoginStatus object you return from the ValidateUser() method. If the Success property is true it means that the login attempt was successful and the user is redirected to the TargetURL using window.location.href property. If the login attempt fails an error message is displayed in the message <div>. The error function is invoked if there is any error making the Ajax call and simply displays an error message to the user.

The following figure shows the login view in action:

image

Create Home controller and Index view

If a login attempt is successful the use is taken to the Index view. So, add the Home controller and also the Index view. The Home controller is supposed to be a secured one and hence add [Authorize] attribute on top of the Index() action method or the HomeController class.

[Authorize]
public class HomeController : Controller
{
    public ActionResult Index()
    {
        return View();
    }
}

The Index view simply outputs a welcome message:

<body>
<h1>Welcome @Membership.GetUser().UserName!</h1>
</body>

The following figure shows a successful run of the Index view:

image

 

To test the application you just developed you need to create a new user account. You can do so either by creating a registration page or by adding a few test users in the Global.asax. For the sake of this example the later approach is alright. Here is how you can create a new user.

protected void Application_Start()
{
  ...
  MembershipCreateStatus status;
  Membership.CreateUser("User1", 
  "some_password_here", "user1@somewebsite.com", 
  "question", "answer", true, out status);
}

That's it! The Ajax login for your MVC application is ready :-)

 READ MORE
Creating Cascading DropDownLists Using ASP.NET MVC 4 And JQuery

Sometimes you need to display DropDownLists in your ASP.NET MVC views such that values in one DropDownList are dependent on the value selected in another DropDownList. The most common example of such a functionality is countries and states DropDownLists where based on a selected country you need to populate the states DropDownList. This article shows how such a cascading DropDownLists can be developed using ASP.NET MVC and jQuery.

Have a look at the following figure that shows two DropDownLists:

image

As you can see the country DropDownList contains a list of countries along with the first entry of "Please select". Upon selecting a country the states DropDownList displays the states belonging to the selected country. When the page is loaded the country DropDownList has "Please select" entry selected and states DropDownList is disabled. Upon selecting a country the states DropDownList is enabled so that state selection can be made. Clicking on the Submit button submits the form to an action method for further processing.

Begin by creating a new ASP.NET MVC4 project based on empty project template. Add Scripts folder to the project and place jQuery library into it. Then add HomeController to the Controllers folder. In a real world scenario you will get countries and states from a database. Here, for the sake of simplicity, we will use some hardcoded country and state values.

Now add the following action method to the HomeController:

public ActionResult Index()
{
  List<string> items = new List<string>();
  items.Add("Please select");
  items.Add("USA");
  items.Add("UK");
  items.Add("India");
  SelectList countries = new SelectList(items);
  ViewData["countries"] = countries;
  return View();
}

The above code shows Index() action method. Inside the Index() method a generic List of strings is created to hold country names and a few countries are added to it. The DropDownList HTML helper of ASP.NET MVC requires its data in the form of SelectList object. Hence a SelectList is created based on the countries List. The SelectList object is passed to the view using countries ViewData variable.

Next, add another action method to the HomeController as shown below:

public JsonResult GetStates(string country)
{
  List<string> states = new List<string>();
  switch (country)
  {
    case "USA":
      states.Add("California");
      states.Add("Florida");
      states.Add("Ohio");
      break;
    case "UK":
      //add UK states here
      break;
    case "India":
      //add India states hete
      break;
  }
  return Json(states);
}

As you can see the GetStates() action method accepts a string parameter named country and returns JsonResult. The GetStates() returns JsonResult because this method will be called using jQuery and states information is to be returned as JSON data. The GetStates() method contains a simple switch statement that adds a few states to states List based on the country value. Finally, the states generic List is returned to the caller using Json() method. The Json() method converts any .NET object into its JSON equivalent.

Now, add Index view to the Views folder and key-in the following markup to it:

<% using(Html.BeginForm("ProcessForm","Home",FormMethod.Post)){ %>
<div>Select Country :</div>
<%= Html.DropDownList("country", ViewData["countries"] as SelectList)%>
<br /><br />
<div>Select States :</div>
<select id="state"></select>
<br /><br />
<input type="submit" value="Submit" />
<%} %>

The Index view consists of a <form> that houses two DropDownLists. The country DropDownList is rendered using DropDownList HTML helper. The first parameter of the DropDownList() helper is the name of the DropDownList and the second parameter is the SelectList object containing DropDownList values. The second DropDownList is added as raw <select> element whose ID is state. Although the <form> is submitted to ProcessForm action this method is not described below as it's not directly related to the functioning of the DropDownLists.

Now, add a <script> reference to jQuery library and also add a <script> block in the head section of the view. Then write the following jQuery code in the <script> block:

$(document).ready(function () {
  $("#state").prop("disabled", true);
  $("#country").change(function () {
    if ($("#country").val() != "Please select") {
       var options = {};
       options.url = "/home/getstates";
       options.type = "POST";
       options.data = JSON.stringify({ country: $("#country").val() });
       options.dataType = "json";
       options.contentType = "application/json";
       options.success = function (states) {
       $("#state").empty();
       for (var i = 0; i < states.length; i++) {
         $("#state").append("<option>" + states[i] + "</option>");
       }
       $("#state").prop("disabled", false);
    };
    options.error = function () { alert("Error retrieving states!"); };
    $.ajax(options);
  }
  else {
    $("#state").empty();
    $("#state").prop("disabled", true);
  }
 });
});

The above code shows the ready() handler. Inside the ready() handler, you first disable the state DropDownList using prop() method. The prop() method sets the disabled DOM property to true and thus disables the state DropDownList. Then the change() method is used to wire change event handler of the country DropDownList. The change event handler will be called whenever selection in the country DropDownList changes. The change handler function first checks value selected in the country DropDownList. If it is other than "Please select", the code creates an options object. The options object holds various settings for the Ajax request to made to the server for retrieving the state values. The url property points to the GetStates() action method. The type property is set to POST indicating that a POST method will be used while making Ajax request. The data property contains JSON representation of the country selected in the country DropDownList. Note that the name of this property has to match with the name of the GetStates() method parameter. The dataType and contentType are set to json and application/json respectively. These properties indicate the data type of the response and request respectively.

The success handler function is called when the Ajax call to GetStates() is successful. The success handler function receives the states returned from the GetStates() method as an array of JSON objects. Inside the success handler you iterate through the states array and add <option> elements to the state DropDownList using append() method. Before appending the newly fetched states the state DropDownList is emptied. Once t he states are populated the disabled property of the states DropDownList is set to true using prop() method.

The error handler function simply displays an error message in an alert dialog.

Finally, an Ajax call is made using $.ajax() method of jQuery and the options object is passed as its parameter.

That's it! Run the application and test whether states are populated as expected.

 READ MORE
Creating Wizard In ASP.NET MVC (Part 3 - JQuery)

In Part 1 and Part 2 of this article series you developed a wizard in an ASP.NET MVC application using full page postback and Ajax helper respectively. In this final part of this series you will develop a client side wizard using jQuery. The navigation between various wizard steps (Next, Previous) happens without any postback (neither full nor partial). The only step that causes form submission to the server is clicking on the Finish wizard button.

The jQuery version of the wizard uses only one view - Index - that contains all the three steps as three <div> elements. Using jQuery code you show only one <div> at a time giving a wizard appearance to the view.

The HomeController class now contains two overloads of Index() action method as shown below:

public class HomeController : Controller
{
  public ActionResult Index()
  {
    return View();
  }

  [HttpPost]
  public ActionResult Index(Customer obj)
  {
    if (ModelState.IsValid)
    {
      NorthwindEntities db = new NorthwindEntities();
      db.Customers.Add(obj);
      db.SaveChanges();
      return View("Success");
    }
    return View();
  }
}

As you can see the second Index() method is marked with [HttpPost] attribute and accepts Customer parameter. Inside it checks whether there are any model state errors or not. In case of any errors Index view is returned otherwise data is added to the database and the Success view is returned.

Currently, there are no model validations on Customer class.  To add then using data annotations you can create a metadata class as shown below:

public class CustomerMetadata
{
  [Required]
  public string CustomerID { get; set; }
  [Required]
  public string CompanyName { get; set; }
  [Required]
  public string Address { get; set; }
  [Required]
  public string City { get; set; }
  [Required]
  public string Country { get; set; }
  [Required]
  public string PostalCode { get; set; }
  [Required]
  public string ContactName { get; set; }
  [Required]
  public string Phone { get; set; }
  [Required]
  public string Fax { get; set; }
}

[MetadataType(typeof(CustomerMetadata))]
public partial class Customer
{
}

As you can see the CustomerMetadata class defines all the properties that are accepted through the wizard. All the properties are marked with [Required] attribute. The CustomerMetadata class is linked with the Customer model class by creating a partial class and then decorating it with [MetadataType] attribute.

Now, add the Index view to the project. The Index view that contains all these <div> elements looks like this:

@model WizardInMVC.Models.Customer

@{
Layout = null;
}

<!DOCTYPE html>

<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Index</title>
</head>
<body>
@using (Html.BeginForm("Index", "Home", FormMethod.Post))
{
<div id="divBasic">
<h1>Step 1 : Basic Details</h1>
@Html.LabelFor(m=>m.CustomerID)<br />
@Html.TextBoxFor(m=>m.CustomerID)
@Html.ValidationMessageFor(m=>m.CustomerID)<br />
@Html.LabelFor(m=>m.CompanyName)<br />
@Html.TextBoxFor(m=>m.CompanyName)
@Html.ValidationMessageFor(m=>m.CompanyName)
<br />
<input type="button" name="nextBtn" value='Next' />
</div>
<div id="divAddress">
<h1>Step 2 : Address Details</h1>
@Html.LabelFor(m=>m.Address)<br />
@Html.TextBoxFor(m=>m.Address)
@Html.ValidationMessageFor(m=>m.Address)
<br />
@Html.LabelFor(m=>m.City)<br />
@Html.TextBoxFor(m=>m.City)
@Html.ValidationMessageFor(m=>m.City)
<br />
@Html.LabelFor(m=>m.Country)<br />
@Html.TextBoxFor(m=>m.Country)
@Html.ValidationMessageFor(m=>m.Country)
<br />
@Html.LabelFor(m=>m.PostalCode)<br />
@Html.TextBoxFor(m=>m.PostalCode)
@Html.ValidationMessageFor(m=>m.PostalCode)
<br />
<input type="button" name="prevBtn" value='Previous' />
<input type="button" name="nextBtn" value='Next' />
</div>
<div id="divContact">
<h1>Step 3 : Contact Details</h1>
@Html.LabelFor(m=>m.ContactName)<br />
@Html.TextBoxFor(m=>m.ContactName)
@Html.ValidationMessageFor(m=>m.ContactName)
<br />
@Html.LabelFor(m=>m.Phone)<br />
@Html.TextBoxFor(m=>m.Phone)
@Html.ValidationMessageFor(m=>m.Phone)
<br />
@Html.LabelFor(m=>m.Fax)<br />
@Html.TextBoxFor(m=>m.Fax)
@Html.ValidationMessageFor(m=>m.Fax)
<br />
<input type="button" name="prevBtn" value='Previous' />
<input type="submit" name="nextBtn" value='Finish' />
</div>
}
</body>
</html>

As you can see there are three <div> elements namely divBasic, divAddress and divContact. They contain various form fields for the respective wizard step. The markup shown above is essentially the summation of the markups in individual views from the Part 1 and Part 2 examples. This markup is quite straightforward. There is a minor change though - the Previous and Next buttons are of type button rather than submit. This is because these buttons no longer cause form submission. To turn the above markup into a wizard you need to write some jQuery code as shown below:

$(document).ready(function () {
  $("div").hide();
  $("div:first").show();
  $(":button").click(function () {
    var parentDiv = $(this).parent();
    $("div").hide();
    if($(this).val()=="Previous")
    {
      var prevDiv = parentDiv.prev();
      prevDiv.show();
    }
    if ($(this).val() == "Next") {
      var nextDiv = parentDiv.next();
      nextDiv.show();
    }
  });
});

As you can see the above jQuery code first hides all the <div> elements from the view. This is done using the element selector and hide() method. Then the first <div> element is made visible using :first selector and show() method. This way initially when the page loads only the first wizard step will be visible.

The code then wires event handlers for the click event of the Previous and Next buttons. This is done by selecting these buttons using :button selector and then using click() method. Notice that inside the click event handler nowhere we hardcode the IDs of various <div> elements. This way adding or removing a wizard step doesn't need any change in the jQuery code. Inside the click event handler, the code retrieves a reference to the parent <div> element of the button being clicked. This is done using parent() method called on this. The code then hides all the <div> elements. It then checks the button that was clicked - Previous or Next. If Previous button is clicked a reference to the previous <div> element is retrieved using prev() method called on parentDiv variable. Similarly if Next button is clicked, a reference to the next <div> element is retrieved using next() method called on parentDiv. Accordingly, either previous <div> or next <div> is displayed using show() method.

That's it! Test the wizard by running the application and then navigating between wizard steps.

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Load ASP.NET MVC Partial Views Dynamically Using JQuery

Most of the times ASP.NET MVC views are rendered as a result of user navigating to some action. For example, when a user navigates to /home/index in the browser (either through address bar or through a hyperlink), ASP.NET MVC executes the action method and usually returns a view to the browser. This means each view is rendered as a result of a full GET or POST request. At times, however, you may want to load views dynamically through Ajax. This way you can render contents of a view without full page refresh.

Consider the following page:

image

The above page consists of a table that lists customers from the Customers table of Northwind database. Each customer row has two buttons - Customer Details and Order Details. Clicking on the respective button should display customer details and order details from the database. Without Ajax you would have submitted the page back to the server and then returned a view with the corresponding details. Using Ajax you can display the details without causing any postback to the server. This is shown below:

image

As you can see the above figure shows order details for CustomerID ALFKI above the customers table. These details are fetched via Ajax request.

While displaying data through Ajax request you have two options:

  • Fetch raw data from the server and embed it in HTML markup on the client side
  • Fetch HTML markup with data embedded from the server

Although the choice of the approach depends on a situation, it can be said that the former approach is suitable to make calls to Web API or when HTML display is dynamically decided by the client script. The later approach is suitable when ASP.NET MVC strongly typed views (or partial views) are being used to render the UI. In this example we will be using the later approach.

To develop this example, create a new ASP.NET MVC application based on the Empty template. Then add ADO.NET Entity Data Model for Customers and Orders tables of Northwind database. The Customer and Order entities are shown below:

image

Next, add HomeController and write the Index() action method as shown below:

public ActionResult Index()
{
    using (NorthwindEntities db = new NorthwindEntities())
    {
        List<Customer> model = db.Customers.ToList();
        return View(model);
    }
}

The Index() action simply retrieves all the Customer entities from the Customers DbSet and passes them to the Index view.

Now, add another action method - GetView() - to the HomeController as shown below:

public ActionResult GetView(string customerID,string viewName)
{
    object model = null;
    if(viewName=="CustomerDetails")
    {
        using(NorthwindEntities db=new NorthwindEntities())
        {
            model = db.Customers.Find(customerID);
        }
    }
    if (viewName == "OrderDetails")
    {
        using (NorthwindEntities db = new NorthwindEntities())
        {
            model = db.Orders.Where(o => o.CustomerID == customerID)
                      .OrderBy(o => o.OrderID).ToList();
        }
    }
    return PartialView(viewName,model);
}

The GetView() action method accepts two parameters - customerID and viewName. These two parameters are passed through an Ajax request. Depending on the viewName parameter either CustomerDetails partial view is returned to the caller or OrderDetails partial view is returned. These two view need model in the form of a Customer object and a List of Order entities respectively. That's why model variable is declared as object. Once model variable is populated the partial view name and the model is passed to the PartialView() method. Here, we used partial views because the HTML output is to be inserted in an existing page through Ajax.

Next, add one view (Index.cshtml) and two partial views (CustomerDetails.cshtml and OrderDetails.cshtml) to the Home sub-folder of Views folder.

Add the following markup to the CustomerDetails.cshtml partial view:

@model MVCViewsThroughAjax.Models.Customer

<table border="1" cellpadding="10">
    <tr>
        <td>Customer ID :</td>
        <td>@Model.CustomerID</td>
    </tr>
    <tr>
        <td>Company Name :</td>
        <td>@Model.CompanyName</td>
    </tr>
    <tr>
        <td>Contact Name :</td>
        <td>@Model.ContactName</td>
    </tr>
    <tr>
        <td>Country :</td>
        <td>@Model.Country</td>
    </tr>
</table>

The above markup is quite straightforward. The CustomerDetails partial view simply displays CustomerID, CompanyName, ContactName and Country of a Customer in a table.

Now add the following markup to the OrderDetails.cshtml partial page:

@model List<MVCViewsThroughAjax.Models.Order>

<table border="1" cellpadding="10">
    <tr>
        <th>Order ID</th>
        <th>Order Date</th>
        <th>Shipping Date</th>
        <th>Shipped To</th>
    </tr>
    @foreach(var item in Model)
    { 
        <tr>
            <td>@item.OrderID</td>
            <td>@item.OrderDate</td>
            <td>@item.ShippedDate</td>
            <td>@item.ShipCountry</td>
        </tr>
    }
</table>

The above markup iterates through the List of Order entities and renders a table with four columns - OrderID, OrderDate, ShippedDate and ShipCountry.

Now, add the following markup to the Index view:

@model List<MVCViewsThroughAjax.Models.Customer>

...
<html>
<head>
...
</head>
<body>
    <div id="viewPlaceHolder"></div>
    <br /><br />
    <table border="1" cellpadding="10">
        <tr>
            <th>Customer ID</th>
            <th>Company Name</th>
            <th colspan="2">Actions</th>
        </tr>
        @foreach(var item in Model)
        {
            <tr>
                <td>@item.CustomerID</td>
                <td>@item.CompanyName</td>
                <td><input type="button" class="customerDetails" 
                           value="Customer Details" /></td>
                <td><input type="button" class="orderDetails" 
                           value="Order Details" /></td>
            </tr>
        }
    </table>
</body>
</html>

The Index view receives a List of Customer entities as its model and renders a table with CustomerID, CompanyName and two buttons - Customer Details and Order Details.

Now comes the important part - making Ajax calls to display customer details and order details. Noticed the <div> at the beginning of the body section? The viewPlaceHolder is where the output of CustomerDetails.cshtml and OrderDetails.cshtml will be loaded. To do so we will use load() method of jQuery. Here is how that can be done:

$(document).ready(function () {

    $(".customerDetails").click(function (evt) {
        var cell=$(evt.target).closest("tr").children().first();
        var custID=cell.text();
        $("#viewPlaceHolder").load("/home/getview", 
            { customerID: custID, viewName: "CustomerDetails" });
    });

    $(".orderDetails").click(function (evt) {
        var cell = $(evt.target).closest("tr").children().first();
        var custID = cell.text();
        $("#viewPlaceHolder").load("/home/getview", 
           { customerID: custID, viewName: "OrderDetails" });
    });
});

Recollect that Customer Details and Order Details buttons have assigned CSS class of customerDetails and orderDetails respectively. The above jQuery code uses class selector to wire click event handlers to the respective buttons. Inside the click event handler of Customer Details button, the code retrieves the CustomerID from the table row. This is done using closest(), children() and first() methods. The CustomerID is stored in custID variable. Then load() method is called on viewPlaceHolder <div>. The first parameter of the load() method is the URL that will be requested through an Ajax request. The second parameter is a JavaScript object that supplies the data needed by the requested URL. In our example, GetView() action method needs two parameters - customerID and viewName. Hence the object has customerID and viewName properties. The customerID property is set to custID variable and viewName is set to CustomerDetails.

The click event handler of Order Details is similar but loads OrderDetails partial view.

That's it! You can now run the application and try clicking on both the buttons. The following figure shows customer details loaded successfully.

image

Notice that through out the application run the URL shown in the browser address bar remains unchanged indicating that Ajax requests are being made to display customer details and order details.

In the above example Ajax requests were made to /home/getview action. A user can also enter this URL in the browser's address bar producing undesirable results. As a precaution you can check the customerID and viewName parameters inside the GetView() action method (not shown in the above code). If these parameters are empty or contain invalid values you can throw an exception.

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