[2005]

[vanQ]

http://pastebin.com/853709

How can I make the program not give an error message if the user leaves the textboxes empty or puts a letter in them instead of a number.

I'm having trouble with stuff like "Error! Can't change TextBox1 to Integer" or something...

I've tried numerous tricks and asked at IRC, but no use... I'm trying to make it "do nothing" if there is something else than numbers in the textboxes.

[gavio]

Add some error trapping:

'...
Public Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    On Error GoTo eh
[B]        '...
        'your code...
        '...[/B]
    Exit Sub
eh:
    MsgBox("Wrong input.", MsgBoxStyle.Exclamation, "Error")
End Sub
'...

[vanQ]

But if I want to avoid ANY notifications or messageboxes? Just that the program doesn't do anything

[stimbo]

With .NET you shouldn't use On Error

Use this instead:

Try
        'Normal Code here
 
        Catch ex As Exception
 
        End Try

Just don't put anything in the Catch part of the code

[gavio]

Then just remove the "MsgBox(...)" line under "eh:".

[jmcilhinney]

For half a picosecond's more efficiency, don't declare an Exception object in your Catch block if you're not going to use it:

Try
    'Do something.
Catch
    'Do nothing.
End Try

Having said that, you should always avoid throwing exceptions if it's at all possible. Converting the contents of a TextBox to a number doesn't need to throw an exception under any circumstances:

Dim number As Integer
 
If Integer.TryParse(myTextBox.Text, number) Then
    'The "number" variable now contains the parsed value.
End If

TryParse returns a Boolean that indicates whether the conversion was successful. If it returns False you just do nothing.

[RobDog888]

Then just remove the "MsgBox(...)" line under "eh:".

No, for .NET code you should use .NET code and not VB 6 "On Error GoTo"