MVVM newbie question - this doesn't seem to work with databinding - WPF Discussion Boards

9-Dec-09 20:09

Maybe set the Border's Background property...

<Border Background="{TemplateBinding Background}" CornerRadius="5,5,5,5" BorderThickness="1,1,1,1" RenderTransformOrigin="0.5,0.5" x:Name="border" BorderBrush="#FFFFFFFF">

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: Rounded ListBox

shanmugarajaa9-Dec-09 22:13

shanmugarajaa

9-Dec-09 22:13

Yes i got that.after adding border background i get that colr.
I cannot get text display.
Im pressing button,then text display in listbox.But it didnot display.

private void button2_Click(object sender, RoutedEventArgs e)
{
MessageBox.Show("2nd Button form C#");
string str = "C#item";
listBox1.Items.Add(str);
}

Re: Rounded ListBox

Mark Salsbery10-Dec-09 6:34

WPF OpenFileDialog and FolderBrowserDialog

10-Dec-09 6:34

shanmugarajaa wrote:
Im pressing button,then text display in listbox.But it didnot display.

Your template doesn't provide an items host.

There's an example of a rounded listbox in the documentation
(scroll down to see the different samples):

ItemsControl.ItemsPanel Property[^]

There's also a complete sample template for listbox and many
other controls...

ListBox ControlTemplate Example[^]

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

ausadmin9-Dec-09 8:47

ausadmin

9-Dec-09 8:47

I am wondering if anyone can point me to some code (or DLL) to build a native OpenFileDialog and FolderBrowserDialog in wpf / xaml, rather than using the System.Windows.Forms controls?

We have now replaced the Forms MessageBox with a native WPF taskdialog, which looks much better and behaves more consistently. I would like to do the same for OpenFileDialog and FolderBrowserDialog.

Thanks,
Tim

Re: WPF OpenFileDialog and FolderBrowserDialog

Mark Salsbery9-Dec-09 10:22

Re: WPF OpenFileDialog and FolderBrowserDialog

9-Dec-09 10:22

WPF has a OpenFileDialog class in the Microsoft.Win32 namespace.

For Folder Browser dialog, see my blog[^]

I thought Pete O'Hanlon was working on a WPF version at one time Smile | :)

It's definitely a project to make a WPF version to replace the OS
dialogs...

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Pete O'Hanlon9-Dec-09 10:59

Pete O'Hanlon

9-Dec-09 10:59

I have been working on one - it's something that I keep coming back to when I have some free time. It's a hell of a complex beast though, as I'm trying to make it completely skinnable.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

Re: WPF OpenFileDialog and FolderBrowserDialog

ausadmin31-Jan-10 10:04

ausadmin

31-Jan-10 10:04

I've only just been able to get back to this question - sorry for the long delay in responding. I guess it looks like this is a complex issue - I'll keep wrapping the System.Windows.Forms controls for the time being, and look out for further developments on this question. Hopefully Microsoft might build something into a future version...
Thanks,
Tim

MVVM newbie question - this doesn't seem to work with databinding

Judah Gabriel Himango9-Dec-09 7:37

Re: MVVM newbie question - this doesn't seem to work with databinding

9-Dec-09 7:37

I've got a 3rd party control:

// 3rd party control, I don't have the source to it.
class Foo : SomeWPFControl, INotifyPropertyChanged
{
   public DateTime Start { get; }
   public event PropertyChangedEventHandler PropertyChanged;
}

I slap this control on my view. Then I code up a little ViewModel. All is good.

I need to do work in my ViewModel when the control's Start property changes. How do you recommend doing this?

Attempt #1: I tried creating a DateTime property in my view model, then binding the control's .Start property to my property in the ViewModel, but that didn't work because "Start is a read-only property". Fail.

Attempt #2: I can listen to control.PropertyChanged inside my view, and when it fires, call some function on my ViewModel. But that doesn't seem very MVVMish. Fail?

Religiously blogging on the intarwebs since the early 21st century: Kineti L'Tziyon
Judah Himango

Ian Shlasko9-Dec-09 8:10

Re: MVVM newbie question - this doesn't seem to work with databinding

9-Dec-09 8:10

Have you tried, in the binding, specifying "Mode=OneWayToSource"?

If that doesn't work, then if I'm interpreting this correctly, #2 is probably the way to go.

Proud to have finally moved to the A-Ark. Which one are you in?
Author of Guardians of Xen (Sci-Fi/Fantasy novel)

Judah Gabriel Himango9-Dec-09 8:11

Re: MVVM newbie question - this doesn't seem to work with databinding

9-Dec-09 8:11

Yeah, I still get a compiler error when specifying Mode = OneWayToSource. Frown | :(

Religiously blogging on the intarwebs since the early 21st century: Kineti L'Tziyon
Judah Himango

Ian Shlasko9-Dec-09 8:14

Re: MVVM newbie question - this doesn't seem to work with databinding

9-Dec-09 8:14

Strange... Might not be set up properly as a DependencyProperty. #2 might be your only option, unfortunately.

Proud to have finally moved to the A-Ark. Which one are you in?
Author of Guardians of Xen (Sci-Fi/Fantasy novel)

Judah Gabriel Himango9-Dec-09 11:02

Re: MVVM newbie question - this doesn't seem to work with databinding

9-Dec-09 11:02

There is a DependencyProperty on the class:

public Foo
{
   public static DependencyProperty StartDateProperty;

   public DateTime StartDate
   {
      get { ... }
   }
}

The only way to change the StartDate is by clicking a button in the 3rd party control.

Religiously blogging on the intarwebs since the early 21st century: Kineti L'Tziyon
Judah Himango

Ian Shlasko9-Dec-09 11:31

Re: MVVM newbie question - this doesn't seem to work with databinding

9-Dec-09 11:31

Hmm, strange way of setting it up...

I mean, you could bind another control to that value, but you can't bind the "StartDate" to a CLR object.

Yeah, I don't see a solution here other than hooking PropertyChanged.

Proud to have finally moved to the A-Ark. Which one are you in?
Author of Guardians of Xen (Sci-Fi/Fantasy novel)

Judah Gabriel Himango9-Dec-09 11:34

Re: MVVM newbie question - this doesn't seem to work with databinding

9-Dec-09 11:34

Alright, well that's a legitimate answer, too. Thanks.

I'm mostly a newb when it comes to WPF, and definitely a newb when it comes to MVVM. I just wanted to be sure I wasn't doing things improperly. If this is the only way to make this work, alrighty.

Religiously blogging on the intarwebs since the early 21st century: Kineti L'Tziyon
Judah Himango

Ian Shlasko9-Dec-09 13:08

Re: MVVM newbie question - this doesn't seem to work with databinding

9-Dec-09 13:08

Yeah, it's not ideal, but you do what you have to do, right?

Proud to have finally moved to the A-Ark. Which one are you in?
Author of Guardians of Xen (Sci-Fi/Fantasy novel)

Pete O'Hanlon9-Dec-09 10:11

Pete O'Hanlon

9-Dec-09 10:11

Is the Start property in the control readonly? What is the mechanism for updating this property?

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

Re: MVVM newbie question - this doesn't seem to work with databinding [modified]

Judah Gabriel Himango9-Dec-09 10:59

Dependancy Property not setting on user control

9-Dec-09 10:59

The Start property is a readonly .NET property:

public DateTime Start
{
   get { ... }
}

There is a static DependencyProperty behind the scenes:

public class Foo
{
   public static DependencyProperty StartProperty;
}

Pete O'Hanlon wrote:
What is the mechanism for updating this property?

If the user clicks a button in the 3rd party control, the .Start will change.

Religiously blogging on the intarwebs since the early 21st century: Kineti L'Tziyon
Judah Himango

modified on Wednesday, December 9, 2009 5:38 PM

rj_hogan9-Dec-09 4:01

rj_hogan

9-Dec-09 4:01

Hello,

Fairly new to WPF so hope this isn't going to be a case of failing to RTFM but I just can't see what has gone wrong.

I am modifying an existing user control to show slightly different data in a list depending on a setting on the control. I have registered the dependency property, added a get;set to use it else where in code and it comes up in the Intellisense in the XAML file. However it is not set to the value I've set it to in the XAML when it is check in the controls constructor.

Here is the relevant bits of the user control:

public partial class StationGroupControl : UserControl
    {
       
        public StationGroupControl()
        {

            try
            {

                if (ShowAggregates != true)
...

        public static DependencyProperty ShowAggregatesProperty =
            DependencyProperty.Register("ShowAggregates",
            typeof(Boolean),
            typeof(StationGroupControl),
            new FrameworkPropertyMetadata(false));

        public Boolean ShowAggregates
        {
            get
            {
                return (Boolean)GetValue(ShowAggregatesProperty);
            }
            set
            {
                SetValue(ShowAggregatesProperty, value);
            }
        }

And the XAML:

<ResearchCtrl:StationGroupControl Name="MultStation" HorizontalAlignment="Left" Margin="-122,0,0,0" Validation.Error="Ctrl_Error" ShowAggregates="True"></ResearchCtrl:StationGroupControl>

Frustratingly this seemed to be working and I then refactored the code down to smaller chunks and it inexplicably stoppped working. It has me doubting if it was ever working properly.

Is there some issue with using a boolean? Something else I need to do? Any way of debugging what is actually happening?

I'm pushed for time on this so any suggestion gratefully received.

Robert.

Re: Dependancy Property not setting on user control

Ian Shlasko9-Dec-09 4:31

Re: Dependancy Property not setting on user control

9-Dec-09 4:31

You're testing the value in the constructor, but it's not being set until AFTER.

The XAML is going to first create the object, THEN start setting properties... So basically what's happening is:

1) Object created
2) Constructor fires, checking ShowAggregates value
3) XAML parser sets the Name property
4) XAML parser sets the HorizontalAlignment property
...
7) XAML parser sets ShowAggregates to true

EDIT: Oh, should have added... The solution is to hook the Initialized event, or override OnInitialized, and do the check there.

Proud to have finally moved to the A-Ark. Which one are you in?
Author of Guardians of Xen (Sci-Fi/Fantasy novel)

rj_hogan9-Dec-09 4:46

rj_hogan

9-Dec-09 4:46

Thanks, as suspected if I'd read the "manual" more closely I'd have spotted that eventually, if I wasn't mildly panicking I probably would have.

Thanks again Ian!

Re: Dependancy Property not setting on user control

rj_hogan9-Dec-09 6:45

rj_hogan

9-Dec-09 6:45

Hello again,

I tried moving the code to the Initialized event but it still wasn't set. I've now moved to the Loaded event and it is there so that's where I've left it for the moment. Let me know if you think this might cause a problem.

Thanks,

Robert.

Re: Dependancy Property not setting on user control

Mark Salsbery9-Dec-09 6:53