Catch Exception Message without stopping - vb.net

Question

I have a simple Try Catch function like:
Try
'do that
Catch
'didn't work now try again
End Try
Now I want the Error / Catch Message to be displayed as Messagebox which works with:
Catch ex As Exception
Messagebox.Show(ex.message)
The issue with that is that it always Stops / Quits the Application after showing me the Error Message which I want to prevent. This should try something until it works and always display the error message without stopping. Is that possible? I need it as compiled exe so just Debugging won't be an option.
As Explanation what I am trying to do:
Basically I have a Timer that executes every 10 Seconds a Request to my Server. It check if my Server is up and connected. If it can't reach my Server it should exactly display me the Message why it didn't connect but it shouldn't stop, it should continue pinging my server 10 seconds later again and try again until it works. The thing is that the exception message sometimes changes so I really need the Exception Message as output

Answer 1

It sounds like right now you have a method that sometimes throws like this:
Public Sub CheckServer()
' do something to test the server
End Function
If the code is not isolated to it's own method like that, it should be.
And you want to call it like this:
Try
CheckServer()
Catch ex As Exception
MessageBox.Show(...)
End Try
I suggest moving the Try/Catch inside the method and making it return a value:
Public Function CheckServer() As String
Try
' do something to test the server
Catch ex As Exception
Return ex.Message
End Try
Return String.Empty
End Function
And then call it like this:
Dim errorMessage As String = CheckServer()
If Not String.IsNullOrEmpty(errorMessage) Then
SendAlert(errorMessage)
End If
Where you also have a separate alert method:
Public Sub SendAlert(alertText As String)
SomeControl.Text += $"{Now} -- {alertText}{vbCrLf}"
End Sub
Notice I did not use MessageBox, because it blocks your UI. But the idea here is this makes it easy to change what you want to do with the alerts when they come in. For example, you might create a toast notification.
Since you're using WinForms, the other thing you could do here is define and then raise an event, rather than returning a value.

Answer 2

Are you using TCPClient to connect ??? If you are, you can just write an IsConnected code. TCP client stays connected until the server or client go out.
The most common error message when a server is not accepting connections is the “server did not properly respond in time message”
Constantly sending the server a request isn’t ideal. You need a one notification to come through when the connection is lost... and then set the timer to constantly try to reconnect.