title: SSRS URL Parameter won't set
body: <p>I have the following c# code in a web form:</p>
  
  <pre><code>protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
          {
              string url;
              string startdate;
              string enddate;
              string costcenter;
              string account;
  
              //url = "http://server/reportserver?/Finance/Cost Spending/Cost Center Details&amp;rs:Command=Render&amp;rc:Parameters=false";
              url = "http://server/reportserver?/Finance/Cost Spending/Cost Center Totals&amp;rs:Command=Render&amp;rc:Parameters=false";
              costcenter = "&amp;costcenter=990";
  
              startdate="&amp;startdate=" + Convert.ToString(txtStartDate.Text);
              enddate = "&amp;enddate=" + Convert.ToString(txtEndDate.Text);
  
              account="&amp;account=" + Convert.ToString(GridView1.SelectedRow.Cells[1].Text);
  
              url =url + startdate + enddate + costcenter + account;
  
  
              //TextBox1.Text = Convert.ToString(GridView1.SelectedRow.Cells[1].Text);
                  Response.Redirect(url, false);
  
          }
  </code></pre>
  
  <p>I've tested a very similer version of this code against another report, the only different being the costcenter parameter.  The other report worked fine, but every time i run this code i get the error: "the 'costcenter' parameter is missing a value".  The only thing i can think of that's significantly different between the two reports is that in the Cost Center Totals report the costcenter parameter is used to populate the accounts parameter (both are multi-select).</p>
  
  <p>Here's what the parameters page looks like:
  <img src="https://i.stack.imgur.com/ygXS1.jpg" alt="parameters"></p>