Check out example codes for "if exist request c#". It will help you in understanding the concepts better.

Code Example 1

protected void Page_Load(object sender, EventArgs e)
    {
         if (!string.IsNullOrEmpty(Request.Params["para"]))
        {
            Response.Write(Request.Params["para"].ToString());
        }
        else
        {
            Response.Write("Request.Params[\"para\"] is null");
        }
    }

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