Thread: trapping non-integer errors

hey, im in my final year of school and im completing a coarse in software development.

We are completing a simple task at the moment of typing an integer into a test box and having it be displayed. This is simple however we have to have a try and catch statement where if a non-integer is inserted it wont freeze up.
the code looks like this so far:

Code:

Public Class Form1

   Private Sub Btnexit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btnexit.Click
       End

   End Sub

   Private Sub btnclear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnclear.Click
       txtEnter.Text = ""

   End Sub

   Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtEnter.TextChanged

   End Sub

   Private Sub btnInteger_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnInteger.Click
       'Dim I As Integer
       Dim str As String
       lbldisplay.Text = Integer.Parse(str)
       Try
           Console.WriteLine("In Try...Block Code")
           lbldisplay.Text = Integer.Parse(str)
       Catch d As NullReferenceException
           Console.WriteLine("Error!!! ... In cash block")
           Console.WriteLine("Nullreferenceexception Caught") ' not complete with errors
       Catch ex As Exception

       End Try

   End Sub


End Class

can anyone see the issue and if so could someone give me some tips to basic structure of code
i have no idea myself

SOMEONE PLEASE HELP


HELP!!
thnx for reading

i also have the files if you need them
thnx

Change the code in btnInteger_Click to this:

Code:

        Dim i As Integer
        If Integer.TryParse(TextBox1.Text, i) Then
            lbldisplay.Text = i.ToString
        Else
            lbldisplay.Text = "could not parse String to Integer"
        End If

The TryParse function combines Parse and TryCatch and returns Boolean value True if successful.

exelent thnak you sooo much ill try it at school tomorrow and get back THNX

hey it worked really well thnx.