how to populate update command in stored procedure

CREATE PROCEDURE DoUpdate
    @ID INT,
    @Value NVARCHAR(MAX)
AS
BEGIN
   UPDATE MyTable SET ValueColumnName=@Value WHERE Id=@ID
END
GO

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand com = new SqlCommand("DoUpdate", con))
        {
        com.CommandType = CommandType.StoredProcedure;
        com.Parameters.AddWithValue("@ID", iDOfRow);
        com.Parameters.AddWithValue("@Value", "My new string");
        com.ExecuteNonQuery();
        }