Cleaning up with Try / Catch / Finally

This lesson covers cleanup with VB.NET's Try / Catch / Finally, with the aim of running something whether or not an error occurred.

A Finally block is where work goes that must run whether or not an error occurred — closing a file, dropping a connection, anything that needs tidying up.

In the sample code, Divide() catches a division-by-zero error with Catch and always shows "Ending the calculation" from the Finally block. Note the Integer? return type, which lets it also return Nothing when there is no value.

A common early stumble is when Finally runs. Even if the Try block returns, Finally runs first — miss that ordering and the flow is easy to misread.

In professional work, Finally is used wherever an external resource such as a file or a database connection has been opened and must reliably be closed, however things end.

📖 Reference code

Module Program
    Function Divide(a As Integer, b As Integer) As Integer?
        Try
            If b = 0 Then
                Throw New Exception("cannot divide by zero")
            End If
            Return a \ b
        Catch ex As Exception
            Console.WriteLine("Error: " & ex.Message)
            Return Nothing
        Finally
            Console.WriteLine("Ending the calculation")
        End Try
    End Function

    Sub Main()
        Console.WriteLine(Divide(10, 2))
        Divide(10, 0)
    End Sub
End Module

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run VB.NET directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).