带参数的存储过程到C＃中的DataGridView中

Question

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.

This is my code currently:

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;
    }
}

This is the error message I get:

Answer 1

you define the parameter twice!

cmd.Parameters.AddWithValue("@varCURRENCY", "USD"); // #1
cmd.Parameters.AddWithValue("@invSTART", "0");
cmd.Parameters.AddWithValue("@invEND", "399999");
cmd.Parameters.AddWithValue("@varCURRENCY", "0"); // #2

remove one of them