c# - Response.Redirect is showing /Account/Login?ReturnUrl=%2f -

i struct redirect thing in asp.net web application c#.

when enter login page , complete fuctionalities , redirect next page url /login?returnurl=%2f been shown.

so googled issue , added these lines in web.config

  <appsettings>     <add key="autoformsauthentication" value="false" />     <add key="enablesimplemembership" value="false"/>   </appsettings>      <authentication mode="forms">       <forms loginurl="~/account/login.aspx" timeout="43280" />     </authentication> 

but still same url been displayed when response.redirect("selectapp.aspx"); in selectapp.aspx webform placed under account folder in login.aspx placed.

   protected void loginbutton_click(object sender, eventargs e)         {             con.open();             sqlcommand cmd = new sqlcommand("select * usermaster user_name =@username , user_pwd1=@password", con);             //string enpwd = encode(password.text);             cmd.parameters.addwithvalue("@username", username.text);             cmd.parameters.addwithvalue("@password", password.text);             sqldataadapter da = new sqldataadapter(cmd);             datatable dt = new datatable();             da.fill(dt);             if (dt.rows.count > 0)             {                 response.redirect("selectapp.aspx");             }             else             {                 clientscript.registerstartupscript(page.gettype(), "validation", "<script language='javascript'>alert('invalid username , password')</script>");             }         } 

i have added code above. not getting solution problem.

before redirect "selectapp.aspx". try adding formsauthentication.setauthcookie(username.text.trim(), false);