Pass Query String and retrieve it for one or more than one values in ASP.Net

QueryString:

In ASP.NET QueryString plays very imporatnt role by which we get value(s) from one page to another page(which we send in QueryString).

we send the value in QueryString something like:

Response.Redirect("default.aspx?userId=12");

we also send the value in QueryString like:

Response.Redirect("default.aspx?userId="+txtName.Text.Trim());

and that QueryString value retrive in following way on another(default.aspx) page.

string queryStringValue = Request.QueryString["userId"];

We also send more than one value in the Querystring.

Response.Redirect("default.aspx?userId=12&EmpId=23");

Response.Redirect("default.aspx?userId="+txtName.Text.Trim()+"&EmpId="+txtEmpName.Text.Trim());

and that QueryString value retrive in following way on another(default.aspx) page.

string queryStringValue1 = Request.QueryString["userId"];

string queryStringValue2 = Request.QueryString["EmpId"];