Exeption Variable

[junelis]

I am new at C# and can`t find how to check if variable is defined or exist.
This is what I want to do:

try
            {
                //some sql insert query here       
            }
            catch (Exception er)
            {
                MessageBox.Show(er.Message);
            }
            finally
            {
                //here I want to check that "Exception er" is defined or exist or value is not null
                   if is not defined or not exist or value is null
                   than messagebox show some message
            }
         }

Best regards.

[Davide]

I don't think you can use both catch and finally.
Anyway, show the message box in the try section if the code works, and show a message box in the catch section if the code doesn't work.