@args is not a parameter for procedure

Question

I am trying to call a stored procedure with a string as parameter ( VARCHAR (MAX) ) but again and again it tells my @args parameter is not when it certainly is. This is my test procedure:

IF OBJECT_ID ( 'TEST', 'P' ) IS NOT NULL   
    DROP PROCEDURE TEST;  
GO

CREATE PROCEDURE TEST (@args varchar (max)) AS
BEGIN
    EXEC sp_execute_external_script
    @language = N'R'
    , @script = N'OutputDataSet <- as.data.frame(...);'
    , @params = N'@args varchar(max)'
    , @args = @args
WITH RESULT SETS ((...));
RETURN 0;
END

If I call it from management studio, it works:

SET LANGUAGE ENGLISH
EXEC dbo.TEST @args = 'long string'
GO

but not through C#

public static void Main()
{
    Console.WriteLine("Connection test!");
    Console.WriteLine("Press ESC to stop");

    string ConnectionString = "...";
    SqlConnection conn = new SqlConnection(ConnectionString);
    SqlCommand    cmd  = new SqlCommand("TEST");
    SqlDataReader rdr  = null;

    string args = "very long string";

    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Connection  = conn;
    cmd.Parameters.Add("@args", SqlDbType.VarChar, -1).Value = args;
    conn.Open();

    var returnParameter = cmd.Parameters.Add("@ReturnVal", SqlDbType.Int);
    returnParameter.Direction = ParameterDirection.ReturnValue;
    try { cmd.ExecuteNonQuery(); } // @args is not a parameter for TEST Procedure
    catch (SqlException ex)

I am not reusing any parameter which is just a varchar(max). Any ideas?

Answer 1

Finally I found the error which was extremely silly.

Short answer: added the SQL USE statement before dropping and creating the proc.

USE myDB;
GO

Long answer: It turns out I have 2 DBs and I was creating the SP in master but I had another procedure in my testing DB. So although I deleted the SP, there was another one in the other DB with the same name but different parameters, hence the error. As I could not understand why @args was incorrect, I listed the SP params ( https://stackoverflow.com/a/3038470/2846161 , https://stackoverflow.com/a/3038530/2846161 ) and it turned out that the procedure was listed even being deleted, therefore it was replicated.