can I return a message from SQL Server to C# application?

I am using SQL server in my C# application and I was thinking if there is any way to return a message from the SQL Server directly to the MessageBox.Show

Right now I am using RETURN 999 and sending the value to C# then implementing and IF return_value = 999 the MessageBox.Show

You could use an OUTPUT parameter and return any varchar()/string message you desire.

I think that it would be difficult to return a message back directly from SQL Server to a messagebox control's show event. However, you could explore setting up a Delegate and a CallBack routine that could accomplish your desired results.

You may wish to post your issue on one of the WinForms forums, where you are more likely to get the help needed.