JsonResult Type in MVC

The following is a brief description of the Sample.cshtml file:

• The HTML body contains a label, about, to describe the functionality and one input button with an onclick of the UpdateUserDetail() function.
  
• The JavaScript part contains the jQuery reference and it contains two functions.
  
• GetSampleUsersList() will return the sample users in a stringified JSON format.
  
• UpdateUserDetail() sends the ajax request of post type for JsonDemoController with UpdateUserDetail action.

Step 4. A Create Action method named UpdateUsersDetail in the JsonDemoController as in the following and put a breakpoint in this method on the first line of code to help to trace the details.

/// <summary>  
/// Update the user details  
/// </summary>  
/// <param name="usersJson">users list in JSON Format</param>  
/// <returns></returns>  
[HttpPost]  
public JsonResult UpdateUsersDetail(string usersJson)  
{  
    var js = new JavaScriptSerializer();  
    UserModel[] user = js.Deserialize<UserModel[]>(usersJson);  
  
    //TODO: user now contains the details, you can do required operations  
    return Json("User Details are updated");  
}

Step 5. Build and run the application (hit F5) with the URL (http://localhost:49568/JsonDemo/Sample) then the resultant screen looks like the following.

Step 6. Now, click on the “Update User Detail” button as it appears in the aforesaid screenshot. Then the resultant screen looks like the following.

Step 7. Just review the preceding image, you can identify that you are able to send the JSON data to the controller action from the client side and as well as you have deserialized the JSON data and assigned that data to the UserModel entity.

Scenario 4. How to handle a huge amount of JSON Data

In this scenario, you will get an idea of how to send a huge amount of JSON Data. Actually, in certain scenarios, you must send a huge amount of data from a controller to a view. In that case, the following example will be helpful to you.

Step 1. Create one method named GetUsersHugeData() as in the following. It just helps to generate sample user data.

/// <summary>  
/// Get the huge list of users  
/// </summary>  
/// <returns></returns>  
private List<UserModel> GetUsersHugeData()  
{  
    var usersList = new List<UserModel>();  
    UserModel user;  
    for (int i = 1; i < 51000; i++)  
    {  
        user = new UserModel  
        {  
            UserId = i,  
            UserName = "User-"+i,  
            Company = "Company-"+i  
        };  
        usersList.Add(user);  
    }  

    return usersList;  
}

Step 2. Create an Action method named GetUsersHugeList() like the following in the JsonDemoController.cs file.

/// <summary>  
/// Get the huge list of Users  
/// </summary>  
/// <returns></returns>  
public JsonResult GetUsersHugeList()  
{  
    var users = GetUsersHugeData();  
    return Json(users, JsonRequestBehavior.AllowGet);  
}

Step 3. Now, build and run (hit F5) the application with the URL (http://localhost:49568/JsonDemo/GetUsersHugeList) then the error screen appears like the following.

Step 4. To fix the preceding error add the following code in the JsonDemoController file. This methods helps to update the MaxJsonLength property value to Int32.MaxValue.

 /// <summary>  
/// Override the JSON Result with Max integer JSON lenght  
/// </summary>  
/// <param name="data">Data</param>  
/// <param name="contentType">Content Type</param>  
/// <param name="contentEncoding">Content Encoding</param>  
/// <param name="behavior">Behavior</param>  
/// <returns>As JsonResult</returns>  
protected override JsonResult Json(object data, string contentType,  
    Encoding contentEncoding, JsonRequestBehavior behavior)  
{  
    return new JsonResult()  
    {  
        Data = data,  
        ContentType = contentType,  
        ContentEncoding = contentEncoding,  
        JsonRequestBehavior = behavior,  
        MaxJsonLength = Int32.MaxValue  
    };  
}

In the same way, you can increase the RecursionLimit property value. Also if you require JsonData with a depth (nested levels) greater than 100.

Step 5. Now, build and run (hit F5) the application with the URL (http://localhost:49568/JsonDemo/GetUsersHugeList) and then the huge data result appears instead of an error.

I have provided the formatted complete code for the JsonDemoController.cs file for what you have done until now in the aforesaid scenarios.

using System;  
using System.Collections.Generic;  
using System.Text;  
using System.Web.Mvc;  
using System.Web.Script.Serialization;  
using JsonResultDemo.Models;  
  
namespace JsonResultDemo.Controllers  
{  
    public class JsonDemoController : Controller  
    {  
        #region ActionControllers  
  
        /// <summary>  
        /// Welcome Note Message  
        /// </summary>  
        /// <returns>In a JSON Format</returns>  
        public JsonResult WelcomeNote()  
        {  
            bool isAdmin = false;  
            //TODO: Check the user if it is admin or normal user, (true-Admin, false- Normal user)  
            string output = isAdmin ? "Welcome to the Admin User" : "Welcome to the User";  
  
            return Json(output, JsonRequestBehavior.AllowGet);  
        }  
  
        /// <summary>  
        /// Get tthe Users data in JSON Format  
        /// </summary>  
        /// <returns></returns>  
        public JsonResult GetUsersData()  
        {  
            var users = GetUsers();  
            return Json(users, JsonRequestBehavior.AllowGet);  
        }  
  
        /// <summary>  
        /// Sample View  
        /// </summary>  
        /// <returns></returns>  
        public ActionResult Sample()  
        {  
            return View();  
        }  
  
        /// <summary>  
        /// Update the user details  
        /// </summary>  
        /// <param name="usersJson">users list in JSON Format</param>  
        /// <returns></returns>  
        [HttpPost]  
        public JsonResult UpdateUsersDetail(string usersJson)  
        {  
            var js = new JavaScriptSerializer();  
            UserModel[] user = js.Deserialize<UserModel[]>(usersJson);  
  
            //TODO: user now contains the details, you can do required operations  
            return Json("User Details are updated");  
        }  
          
        /// <summary>  
        /// Get the huge list of Users  
        /// </summary>  
        /// <returns></returns>  
        public JsonResult GetUsersHugeList()  
        {  
            var users = GetUsersHugeData();  
            return Json(users, JsonRequestBehavior.AllowGet);  
        }  

        #endregion  


        #region Methods  
  
        /// <summary>  
        /// Get the Users  
        /// </summary>  
        /// <returns></returns>  
        private List<UserModel> GetUsers()  
        {  
            var usersList = new List<UserModel>  
            {  
                new UserModel  
                {  
                    UserId = 1,  
                    UserName = "Ram",  
                    Company = "Mindfire Solutions"  
                },  
                new UserModel  
                {  
                    UserId = 1,  
                    UserName = "chand",  
                    Company = "Mindfire Solutions"  
                },  
                new UserModel  
                {  
                    UserId = 1,  
                    UserName = "Abc",  
                    Company = "Abc Solutions"  
                }  
            };  
  
            return usersList;  
        }  
  
        /// <summary>  
        /// Get the huge list of users  
        /// </summary>  
        /// <returns></returns>  
        private List<UserModel> GetUsersHugeData()  
        {  
            var usersList = new List<UserModel>();  
            UserModel user;  
            for (int i = 1; i < 51000; i++)  
            {  
                user = new UserModel  
                {  
                    UserId = i,  
                    UserName = "User-"+i,  
                    Company = "Company-"+i  
                };  
                usersList.Add(user);  
            }  
  
            return usersList;  
        }  
  
        /// <summary>  
        /// Override the Json Result with Max integer JSON lenght  
        /// </summary>  
        /// <param name="data">Data</param>  
        /// <param name="contentType">Content Type</param>  
        /// <param name="contentEncoding">Content Encoding</param>  
        /// <param name="behavior">Behavior</param>  
        /// <returns>As JsonResult</returns>  
        protected override JsonResult Json(object data, string contentType,  
            Encoding contentEncoding, JsonRequestBehavior behavior)  
        {  
            return new JsonResult()  
            {  
                Data = data,  
                ContentType = contentType,  
                ContentEncoding = contentEncoding,  
                JsonRequestBehavior = behavior,  
                MaxJsonLength = Int32.MaxValue  
            };  
        }  

        #endregion  
    }  
}

You now have an idea of how to use a JsonResult type in MVC application with various scenarios. Now, it's time to test the controller action methods using the JsonDemoController.Test project.

Unit Testing the JsonResult in MVC

The main feature of MVC applications is it supports the Test Data Driven (TDD) approach. Since the Controller file is just a kind of class file, it's easy to implement the Test methods in the Test Project. Now you will learn how to test the JsonResult methods in the test project.

Step 1. Add a class file named “JsonDemoControllerTest.cs” to the JsonResultDemo.Tests projects like the following.

Click on “Class” to open a popup like the following and then update the name as “JsonDemoControllerTest.cs”.

Step 2. After clicking on the “Ok” button then the screen result looks like the following.

Step 3. Now, replace the existing code in the file JsonDeomControllerTest.cs with the following code.

using System;  
using System.Web.Mvc;  
using Microsoft.VisualStudio.TestTools.UnitTesting;  
using JsonResultDemo.Controllers;  
  
namespace JsonResultDemo.Tests.Controllers  
{  
    [TestClass]  
    public class JsonDemoControllerTest  
    {  
        [TestMethod]  
        public void WelcomeNote()  
        {  
            JsonDemoController controller = new JsonDemoController();  
  
            JsonResult result = controller.WelcomeNote();  
            string msg = Convert.ToString(result.Data);  
            // Assert  
            Assert.AreEqual("Welcome to the User", msg);  
        }  
    }  
}

Brief Note about TestMethod of WelcomeNote()

• Create an object for JsonDemoController.
  
• Save the result of JsonDemoController controller method “WelcomeNote” method result in the “result” parameter of the type JsonResult.
  
• The string “msg” is assigned with the value from the JSON Result (result.Data).
  
• In this step, you are checking the expected output with the actual output using the Assert method. In a similar way, the Assert Method provides other options like AreNotEqual, AreSame, IsNotNull and so on.

Step 4. Right-click on the WelcomeNote method and click on “Run Unit Tests” then the screen result looks like the following.

Step 5. You can also do the “Run Tests” by the clicking of (Ctrl +R, T). Then you can view the results in Test Explorer like the following.

Step 6. As you noticed in the Test Explorer screenshot, it contains so many options like “Run All” and Run the selected/required options. You can try with those and will get an idea of it easily.

In a similar way, you can create more test methods and it will be helpful to check the functionality in various cases since it provides correct results or not.

Note: you can download the preceding discussed sample project from the link - Source Code.

Conclusion

I hope this article gives you an idea of JsonResult, JsonResult Properties, the usage of JsonResult with various scenarios and how can you test the JsonResult using the Test Project.

Please provide your valuable suggestions and comments on this.