Question

i have the following stored procedure in sql server and i am trying to take the permission value with C#.

CREATE PROCEDURE [dbo].[GetPermission]
@userName varchar(50),
@permission int output
AS
BEGIN

select @permission = PERMISSION from USERS where UserName = @userName

END;

My C# code is the following:

        SqlCommand cmd = new SqlCommand(
            "sp_getPermission", conn);


        cmd.CommandType = CommandType.StoredProcedure;


        cmd.Parameters.Add(
            new SqlParameter("@UserName", textBox1.Text));
        cmd.Parameters.Add(
           new SqlParameter("@permission", "none"));




        SqlDataReader rdr = null;

        rdr = cmd.ExecuteReader();
        MessageBox.Show( rdr["Permission"].ToString() );

But i get the following error on the last line of C# code:

Invalid attempt to read when no data is present.

Any suggestions?

Answer 1

Let’s simply this:

first, remove the output parameter @permission, then, change your procedure like this:

CREATE PROCEDURE [dbo].[GetPermission]
@userName varchar(50)
AS
BEGIN

select PERMISSION from USERS where UserName = @userName

END;

and for read the permission, use the ExecuteScalar method:

SqlCommand cmd = new SqlCommand(
    "sp_getPermission", conn);


cmd.CommandType = CommandType.StoredProcedure;


cmd.Parameters.Add(
    new SqlParameter("@UserName", textBox1.Text));

var permission = (System.Int32)cmd.ExecuteScalar();