QueryString in ASP.NET

This blog explains -

• What is QueryString?
• Why do we use QueryString?
• How to pass the values through QueryString?
• How to retrieve the values from QueryString?

 QueryString

• Query string is one of the technique to send data from one webform to another through URL.
• Query string consist of two parts (field and value), and each of pair separated by ampersand (&).
• ?(Question Mark), indicates the beginning of a query string and it's value.
• There is a limit on the Query string length. Hence, Query strings cannot be used to send very long data.
• Query strings are visible to the user, hence should not be used to send sensitive information (Like Username, Password), unless encrypted.
• To retrieve the query string value, use Request object's QueryString property.

Lets understand with an example: 

• To create the project -
• Go to Start -> then All Programs and click Microsoft Visual Studio 2010
• Go to File -> New -> Project..., Visual C# , Web. Then select ASP.NET Empty Web Application.
• Provide the project a name and specify the location. 

Next: Right-click on Solution Explorer and add a two web forms (user.aspx, Mas_Employee.aspx) to your project.

 

Send the Values using QueryString :

 

Design your user.aspx as in the following.

 

 

Copythe following code in your button click event to send multiple query string values (Name, DeptNmae) through URL from user.aspxpage to Mas_Employee.aspx.

protected void btnSend_Click(object sender, EventArgs e)
{
   Response.Redirect("/Application /Mas_Employee.aspx?Name=" + txtName.Text + "&DeptName=" + txtDeptName.Text);
}

 Retrieve the values from QueryString:

 

Design your Mas_Employee.aspx as in the following

 

 

To retrieve the QueryString Values (Name, DeptNmae) in Mas_Employee.aspx copy the following code in your Mas_Employee.aspx.cs.

protected void Page_Load(object sender, EventArgs e)
{
   if (!IsPostBack)
   {
      if (Request.QueryString["Name"] != null && Request.QueryString["Name"] != string.Empty)
         lblName.Text = Request.QueryString["Name"];

      if (Request.QueryString["DeptName"] != null && Request.QueryString["Name"] != string.Empty)
         lblDeptName.Text = Request.QueryString["DeptName"];
   }
}

Run the application and Provide Name and DeptName values and then click on Send. At this point you will get the following result.

 

 

Output:

 

 

Conclusion

QueryString are used to pass the data (limited data through URL) from one page to another page . For example. If we want to send one page control values to another page you can use QueryString.

 

I hope you enjoyed it. Please provide your valuable suggestions and feedback if you found this blog helpful.