… and it comes in blue…

Got an email from Kedra A.– a developer/admin in Austin who wanted to know … if the cXML validator I put up this weekend could be done… using WPF.  Why Kedra wanted this in WPF I have no clue – but apparently all of their apps are now being done in… you got it – WPF.  Kedra tried building the project by just grabbing the various functions and subs and copying them into a WPF app and she couldn’t get it to work

I told her I’d take a look at it and see why.

So here it is.  Mission accomplished.  All done.

Okay – I won’t be cruel .. because there are some code differences between any WPF and a normal .NET application. 

Basically there are very very few things in this app that won’t work in WPF.  But there are a few which, for various reasons need to be modified.

Primarilly this is the Richtextbox control and the OpenFileDialog/Showdialog, and these I found out after a bit of digging on the web … can be tricky.

So Kedra – don’t feel bad.  This is intermediate level to upper level stuff and it involves a very very new (for most people) technology. 

Lets take a look at the OpenFileDialog code in the original application and the wpf version here.

If you notice the OpenFileDialog in the new code needs to instantiate the OFDialog as a System.Windows.Forms OpenFileDialog instead of the default that comes with WPF.  Why’d I do that?

'Set up the OpenFileDialog to get the name of the file for loading.
Dim OFDialog As New System.Windows.Forms.OpenFileDialog
With OFDialog
    .FileName = vbNull        'Clear out previous filename
    .FileName = "*.xml"

Simple … the OFDialog that comes with System.Windows.Forms.OpenFileDialog  is an easier to use – and has some richer features than the one that’s baked into WPF which is Microsoft.Win32.OpenFileDialog and has all the functionality of a sockpuppet.  Okay it’s not that bad… at least not until you try to use the ShowDialog to go with it. 

So that’s why… you can see I did this:

If OFDialog.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
    If .FileNames.GetUpperBound(iCount) < 1 Then
        'File selected so put it in the ComboBox

In setting the OFDialog box to the Windows.Forms.OpenFileDialog in the top snippet – I can now use the System.Windows.Forms.DialogResult and it’s various fun toys.  I also wind up with a much nicer OpenFileDialogbox.

I do need to use Import System.Windows.Forms; and yes… this does mean I’m refactoring but it’s a small price on code like this which is a quicky.

But … what other differences are there that you need to be aware of? 

Microsoft.Win32 RichTextboxes differ greatly from their Windows.Forms brothers.  As a rule most of the WPF controls are very similar – and at the same time very different from their cousins.  System.Windows.Controls.Richtextbox and System.Windows.Forms.RichTextBox are close – but no cigar.  If I want to change the text in a RichTextbox in WPF it’s a much different process than it’s Forms cousin. Check out the links above – and compare the code in the link below the the code in the previous post (it’s the same code – just updated for the WPF, and I removed a couple of annoyances I discussed last time).  

 WPF Validator Download Link

Side Note - Kedra also wanted to thank me for doing my samples in VB.NET since its apparently hard to find code samples in VB.NET.  I agree with her for some reason there’s a hundred samples out there and the conversion I also agree is pretty simple… but the fact is there are still a lot of new programmers out there who need some time with the code before their confidence is strong enough to jump into those waters.  (They will get there – we all do – they just need to see shore for a bit longer while they work on their swimming.)  I will continue to do as many samples as i can in VB, but will also try to put them out in C# as well.