How to Get Error message from procedure into display on c#?

STOREDPROCEDURE Create procedure SP_Insert_Staff_Attendance ( @StaffID nvarchar(50), @Name nvarchar(50), @Category nvarchar(50), @Date datetime, @Status nvarchar(50), @ERROR VARCHAR(100) OUT ) AS BEGIN SET NOCOUNT ON; IF NOT EXISTS(SELECT * FROM tbl_Staff_Attendance WHERE Date=@Date and StaffID=@StaffID) -- To Check UserName is exits or not BEGIN INSERT INTO tbl_Staff_Attendance (StaffID,Name,Category,Date,Status) values (@StaffID,@Name,@Category,@Date,@Status) --SET @ERROR=@UserName+' Registered Successfully' END ELSE BEGIN SET @ERROR=@Name + ' Already Exists' END End C# cmd.Parameters.Add("@ERROR", SqlDbType.Char, 500); cmd.Parameters["@ERROR"].Direction = ParameterDirection.Output; cmd.ExecuteNonQuery(); message = (string)cmd.Parameters["@ERROR"].Value; con.Close();