title: Stored Procedure with parameters into DataGridView in C#
body: <p>I'm new to C# and I want to simply pull data from SQL database into my C# application in Visual Studios.
  I have been using a mix of guides to do this but cannot find what is wrong. The code works if I want to recall a table without specifying parameters otherwise it fails.</p>
  
  <p>This is my code currently:</p>
  
  <pre><code>string CS =  "Server = server-sql1;Database=Accounts;Trusted_connection=true";
  using (SqlConnection con = new SqlConnection(CS))
  {
      SqlCommand cmd = new SqlCommand("ASP_SLINVOICE", con);
  
      //specify that it is a stored procedure and not a normal proc
      cmd.CommandType = System.Data.CommandType.StoredProcedure;
  
      //list the parameters required and what they should be
      cmd.Parameters.AddWithValue("@varCURRENCY", "USD");
      cmd.Parameters.AddWithValue("@invSTART", "0");
      cmd.Parameters.AddWithValue("@invEND", "399999");
      cmd.Parameters.AddWithValue("@varCURRENCY", "0");
  
      con.Open();
      cmd.ExecuteNonQuery();
  
      using(SqlDataAdapter adap = new SqlDataAdapter(cmd))
      {
          DataTable dt = new DataTable();
          adap.Fill(dt);
          dataGridView1.DataSource = dt;
      }
  }
  </code></pre>
  
  <p>This is the error message I get:</p>
  
  <p><img src="https://i.stack.imgur.com/cASU0.jpg" alt="enter image description here"></p>