Query Strings in ASP.Net

A QueryString is a collection of characters input to a computer or web browser. A Query String is helpful when we want to transfer a value from one page to another. When we need to pass content between the HTML pages or aspx Web Forms in the context of ASP.NET, a Query String is very easy to use and the Query String follows a separating character, usually a Question Mark (?). It is basically used for identifying data appearing after this separating symbol. A Query String Collection is used to retrieve the variable values in the HTTP query string. If we want to transfer a large amount of data then we can't use the Request.QueryString. Query Strings are also generated by form submission or can be used by a user typing a query into the address bar of the browsers. Query Strings are contained in request headers. A Query String collection is a parsed version of the QUERY_STRING variable in the Server Variables collection. It enable us to retrieve the QUERY_STRING variable by name. When we use parameters with Request.QueryString, the server parses the parameters sent to the request and returns the effective or specified data.

Syntax of Query String

Request.QueryString(variable)[(index).count].

Step 1

Start Visual Studio.

 

Figure 1: Start Visual Studio 

Step 2

Now for creating a website, click on the file, go to new and click on the website.

 

Figure 2: Create Website

Step 3

Now we add the two web forms to the website.

 

Figure 3: Add Web form 

Step 4

 

We design the web form as in the following:

 

Figure 4: Design form

Step 5

After designing the web form, we need to write the following code in the button click.

1. protected void Button1_Click(object sender, EventArgs e)   
2. {  
3.     Response.Redirect("default2.aspx ?firstname=" + TextBox1.Text + "&lastname=" + TextBox2.Text);  
4. }  

 Step 6

In the second web form we take the one lable for displaying the values of the first page. For receiving the value from the first page we write the following code on the page_load of the second page.

1. protected void Page_Load(object sender, EventArgs e)   
2. {  
3.     string firstname = Request.QueryString["firstname"];  
4.     string lastname = Request.QueryString["lastname"];  
5.     Label1.Text = "welcome" + firstname + " " + lastname;  
6. }  

 Step 7

Now we need to execute the website by using the F5 key. After execution we give the input in the textboxes like this:

Figure 5: Execute Web Form

Figure 6: Input in the Textboxes

Step 8

After giving the values, we click on the Submit button then the following window will appear.

Figure 7: Final Window

Summary

In this article, I explained how to use Query Strings in ASP.NET, now you can easily do these operations in your projects for transferring a value of one page to another page.

I hope this article will be helpful for the beginners if they want to transfer data from one page to the another.

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source: http://www.c-sharpcorner.com/UploadFile/ca2535/query-string-in-Asp-Net/