Query String allows you to pass values between the asp.net pages.

Let us say, you are navigating to below URL

In above URL, you are navigating to a page called Add.aspx and Number1 and Number2 are query string to page Add.aspx.

To create Query String,

  1. Add a question mark (?) to URL.
  2. After Question mark, give variable name and value separated by equal to (=).
  3. If more than one parameter need to be passed then separate them by ampersand (&).

To read query String,

Say your URL is,

http://localhost:12165/Add.aspx?Number1=72&Number2=27

Then to read query string, on Add.aspx

You can read by passing exact variable name in index or,

You can read, by passing index value as above.

Now, I am going to show you a very basic sample,

  1. I will create a page with two text boxes and one link button.
  2. I will pass text boxes values as query string to other page on click event of link button.
  3. On the other page, I will read the query string value and will add them in display in a label.

I have created a new asp.net application. Then I dragged and dropped two textboxes and one link button on the page. On click event of link button, I am performing the below operation.

I am constructing the URL, as to navigate to Add.aspx page and then appending two query strings from textbox1 text and textbox2 text.

Now, add a page to project say Add.aspx . Drag and drop a label on the page. On the page load event perform the below operation.

 \

So, when you run the application you will get the output as below,

For your reference, the whole source code is given below,

Default.aspx.cs

    1 using System;

    2 using System.Collections.Generic;

    3 using System.Linq;

    4 using System.Web;

    5 using System.Web.UI;

    6 using System.Web.UI.WebControls;

    7 

    8 namespace queryparameterexample

    9 {

   10     public partial class _Default : System.Web.UI.Page

   11     {

   12         protected void Page_Load(object sender, EventArgs e)

   13         {

   14 

   15         }

   16 

   17 

   18         protected void LinkButton1_Click(object sender, EventArgs e)

   19         {

   20             string urltoNaviget = “~/Add.aspx?Number1=” +

   21                                      TextBox1.Text +

   22                                      “&Number2=” +

   23                                      TextBox2.Text;

   24 

   25             LinkButton1.PostBackUrl = urltoNaviget;

   26         }

   27     }

   28 }

   29 

Add.aspx.cs

    1 using System;

    2 using System.Collections.Generic;

    3 using System.Linq;

    4 using System.Web;

    5 using System.Web.UI;

    6 using System.Web.UI.WebControls;

    7 

    8 namespace queryparameterexample

    9 {

   10     public partial class WebForm1 : System.Web.UI.Page

   11     {

   12         protected void Page_Load(object sender, EventArgs e)

   13         {

   14 

   15             string number1 = Request.QueryString[0];

   16             string number2 = Request.QueryString[1];

   17 

   18             // The other way to Read the values

   19             //string number1 = Request.QueryString[“Number1”];

   20             //string number2 = Request.QueryString[“Number2”];

   21 

   22             int result = Convert.ToInt32(number1) + Convert.ToInt32(number2);

   23             Label2.Text = result.ToString();

   24 

   25         }

   26     }

   27 }


 

I hope this post is useful. Thanks for reading. Happy Coding.

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3 thoughts on “Simple Explanation for very beginners of Query String

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