How to pass a query string

Consider the following URL: 

http:// localhost/form.aspx?param1=career¶m2=ride

This html addresses use QueryString property to pass values between pages.

From the URL above the information obtained is:

form.aspx: which is the destination page for your browser.
Param1 is the first parameter, the value of which is set to career
Param2 is the first parameter, the value of which is set to ride

The '?' marks the beginning of the QueryString
'&' is used as a separator between parameters.

private void formButtonSubmit_Click(object sender, System.EventArgs e)
{
Response.Redirect("form.aspx?Param1=" +
this.formTextfieldParam1.Text + "&Param2=" +
this. formTextfieldParam2.Text);
}

The above code is a submit button event handler and it sends the values of the query string to the second page.

The following code demonstrates how to retrieve these valus on the second page:
private void Page_Load(object sender, System.EventArgs e)
{
      this.form2TextField1.Text = Request.QueryString["Param1"];
      this. form2TextField2.Text = Request.QueryString["Param2"];
}

You can also use the following method to retrieve the parameters in the string:

for (int i =0;i < Request.QueryString.Count;i++)
{
        Response.Write(Request.QueryString[i]);
}

Refer