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

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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

Judah Gabriel Himango

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

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

Ian Shlasko9-Dec-09 8:10

Ian Shlasko

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)

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

Judah Gabriel Himango9-Dec-09 8:11

Judah Gabriel Himango

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

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

Ian Shlasko9-Dec-09 8:14

Ian Shlasko

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)

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

Judah Gabriel Himango9-Dec-09 11:02

Judah Gabriel Himango

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

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

Ian Shlasko9-Dec-09 11:31

Ian Shlasko

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)

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

Judah Gabriel Himango9-Dec-09 11:34

Judah Gabriel Himango

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

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

Ian Shlasko9-Dec-09 13:08

Ian Shlasko

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)

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

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

Judah Gabriel Himango

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

Dependancy Property not setting on user control

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

Ian Shlasko

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)

Re: Dependancy Property not setting on user control

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

Mark Salsbery

9-Dec-09 6:53

Shouldn't be a problem!

For study:
WPF Object Lifetime Events[^]

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

Freeze first item in listbox from scrolling.

Member 23244838-Dec-09 10:28

Member 2324483

8-Dec-09 10:28

Hi,

Is there a way in xaml/wpf to freeze first item in listbox from scrolling?

Thanks

DynamicResource not working, but StaticResource does ???

assassin3168-Dec-09 3:18

assassin316

8-Dec-09 3:18

Here is the scenario:

1. Open Visual Studio 2008, create new project...
2. Select WPF Custom Control Library as the project type
3 Open the Generic.xaml resource dictionary located in the Themes folder
4. Add a simple brush such as:

<SolidColorBrush x:Key="BackgroundBrush" Color="Yellow"/>

5. Change the Background property of the nested Borer Control from

Background="{TemplateBinding Background}"

Background="{DynamicResource BackgroundBrush}"

Now when you compile and use this control in any project, the background will NOT be yellow. BUT, if you change the background property to be a StaticResource as such

Background="{StaticResource BackgroundBrush}"

...it will work. Why is this? Why does StaticResource work but not DynamicResource???

Session variables in Silverlight or wcf service

Nekkantidivya7-Dec-09 18:43

Nekkantidivya

7-Dec-09 18:43

Hi,

I am working with a Silver light application with WCF service. In this I have a session variable names "UserId" which will be created in user login.aspx page. Now I need to access this current login UserId into my WCF service.

or

I need to access this UserId sesssion variable in the silver light page and then pass it to WCF service as parameter.

If any one have any idea ti implement any one of the above please reply me.

Thanks in advance.

Re: Session variables in Silverlight or wcf service

Abhinav S10-Dec-09 6:37

Abhinav S

10-Dec-09 6:37

http://www.codeproject.com/answers/45625/Silverlight.aspx[^]

There's nothing left in my right brain and nothing right in my left brain.

Application menu button issue

trey white7-Dec-09 8:40

trey white

7-Dec-09 8:40

I have another issue with the WPF Ribbon control when i have two buttons on the bottom of the Application menu button. When i'm running my app and i click on a button on one of my tabs, it pops up with a user dialog for the user to choose then close. The issue i'm having is when the user clicks on any of the buttons in the dialog and then closes it, the two buttons i have in the Application menu button are disabled for some reason until the user clicks on the menu bar again. Why is that? Is this a known issue or just a quirk in WPF Ribbon? Thanks in advance!

WPF Ribbon bar issue

trey white7-Dec-09 8:35

trey white

7-Dec-09 8:35

how do i disable the mouse scroll in the WPF ribbon bar?
i'm trying to disable this because of the tabs that i have in my ribbon bar shouldn't be accessed until they are properly called on. This causes issues when the user is able to scroll through the tabs
Any ideas or advice would be much appreciated! Cool | :cool:

Re: WPF Ribbon bar issue

trey white7-Dec-09 11:09

trey white

7-Dec-09 11:09

I have found a solution to this(or maybe a work around, not sure) that does what i want it to do
I found the answer here: http://blogs.infragistics.com/forums/p/6887/28951.aspx[^]

This disables the mouse scroll for when the mouse is over the Ribbon bar which is EXACTLY what i needed!
I replied to my own question so that if others had the same problem they could see this answer i found Big Grin | :-D

Error in RoutedEventHandler()

Anu_Bala7-Dec-09 0:04

Anu_Bala

7-Dec-09 0:04

Hi, Im using WPF controls in MFC.IN one dialog i want to get these controls,textbox,button etc.,And for button i wrote function.But it shows error at bolded line as
error C3364: 'System::Windows::RoutedEventHandler' : invalid argument for delegate constructor; delegate target needs to be a pointer to a member function

HWND GetHwnd(HWND parent,CSampleWPF* view,int x, int y, int width, int height)
{
// Create an HwndSource WPF object
System::Windows::Interop::HwndSourceParameters^ sourceParams = gcnew System::Windows::Interop::HwndSourceParameters ("WPFSourceWindow");
sourceParams->PositionX = x;
sourceParams->PositionY = y;
sourceParams->Height = height;
sourceParams->Width = width;
sourceParams->ParentWindow = IntPtr(parent);
sourceParams->WindowStyle = WS_VISIBLE | WS_CHILD;
HwndSource^ source = gcnew System::Windows::Interop::HwndSource(*sourceParams);

view->m_wpfTextBox = gcnew TextBox();
view->m_wpfTextBox->Width=100;
view->m_wpfTextBox->Height=20;
view->m_wpfTextBox->Text = "Some WPF Text";
source->RootVisual = view->m_wpfTextBox;

view->m_Button = gcnew Button();
view->m_Button->Height=60;
view->m_Button->Margin=Thickness(2);
view->m_Button->Background::set(Brushes::SkyBlue);
view->m_Button->Click += gcnew RoutedEventHandler(view->m_Button,&CSampleWPF::OnBtnExit); source->RootVisual = view->m_Button;
return (HWND) source->Handle.ToPointer();
}

void CSampleWPF::OnBtnExit(Object^ sender, RoutedEventArgs^ e)
{
AfxMessageBox(_T("Simple message box."));

}

And also in output,its shows only the button not the textbox.Wats the mistake??

Anu

Using WPF Browser application in website.

Hema Bairavan6-Dec-09 18:02

Hema Bairavan

6-Dec-09 18:02

Hi Peoples,

I have designed a application in WPF browser aplication template.
I need to Publish/Host the same in the IIS server, means i need to access the same from i.e or mozila browser.
can any one help me? how to do the same ,

Thanks in advance.

Last Visit: 31-Dec-99 18:00 Last Update: 1-May-24 7:32

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