MVVM and the ViewModelLocator - WPF Discussion Boards

Getting the size of a control

19-Sep-10 19:57

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WebMaster13-Sep-10 9:47

WebMaster

13-Sep-10 9:47

Hello,

Whenever I try getting the size of a custom control (inside the code), both ActualWidth/Height and DesiredSize returns either Size(0, 0) or Size(Width, Double.NaN) or Size(Width, Double.PositiveInfinity). Same with Height/Width.

Any suggestions?
Thanks,
Theo

Re: Getting the size of a control

PumbaPumba27-Sep-10 6:44

PumbaPumba

27-Sep-10 6:44

Hi Theo,

Are you trying to get the size of the control from inside the control. I mean inside control's

ArrangeOverride

or do you want to get the control's size in application level?

MVVM and the ViewModelLocator

Mycroft Holmes11-Sep-10 23:36

Mycroft Holmes

11-Sep-10 23:36

I'm struggling to identify the correct way to move from one control to another using MVVM. I have implemented the navigation framework and MVVMLight. UserVM is the viewmodel and it is a static property the ViewModelLocator

public static UserDetailsVM UserDetailsVMStatic
{
    get
    {
        if (_UserDetailsVM == null)
        {
            CreateUserDetailsVM();
        }
        return _UserDetailsVM;
    }
}

So I have a control with a list of users in a datagrid, the user clicks on the hyperlinkbutton and navigates to the details form. The ID is correctly passed via the navigation but I'm not using it yet as I expect to use the existing VM.

The details control binds to the static VM and should show the selected user details from the datagid control (this works within the same page).

This control binding does not return the selected user details but the FIRST users details.

DataContext="{Binding UserDetailsVMStatic, Source={StaticResource Locator}}"

The textbox binding should show the user details of the selected user from the list page

<TextBox Grid.Row="2" Grid.Column="1" Text="{Binding EditableUserDetails.Email, Mode=TwoWay}"/>

Except I already have a VM created to service the datagrid control and it has the selected item in a property.

How can I use the existing VM in the details form.
Do I have to chase through the staticresource dictionary to get the VM from the locator or is there a way to do this in XAML.

Never underestimate the power of human stupidity
RAH

Re: MVVM and the ViewModelLocator - Solved

Mycroft Holmes14-Sep-10 16:06

Mycroft Holmes

14-Sep-10 16:06

So the question turned out to be wrong.

What I wanted to do was use the same viewmodel to service the 2 views. This was achieved by binding both views to the STATIC viewmodel in the viewmodellocator.

This can be done either code behind or xaml

public NTFXPastCash()
{
    InitializeComponent();
    this.Layoutroot.DataContext = ViewModels.ViewModelLocator.NTFXPastCashVMStatic;
}

Never underestimate the power of human stupidity
RAH

WPF custom control DepencyProperty

wpfcomputer11-Sep-10 9:12

wpfcomputer

11-Sep-10 9:12

Hello.
I create a UseControl and i'd like to add an collection DependencyProperty.

<br />
  ......<br />
       private static  DependencyPropertyKey ItemsPropertyKey = <br />
            DependencyProperty.RegisterReadOnly("MyItems",<br />
            typeof(List<TextBlock>), typeof(AutoCompleteTextBox),<br />
            new FrameworkPropertyMetadata(new List<TextBlock>(), MyListChanged)<br />
       );<br />
<br />
       static void MyListChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)<br />
       {<br />
          //my code   <br />
       }<br />
<br />
       public List<TextBlock> MyItems<br />
       {<br />
            get { return (List<TextBlock>)GetValue(FileNameProperty); }<br />
            set { SetValue(FileNameProperty, value); }<br />
       }<br />
   .........<br />

How can I do the same with a collection of string and not of TextBlock?

thanks

Abhishek Sur11-Sep-10 10:54

Abhishek Sur

11-Sep-10 10:54

What is the problem with List<string> ?

AFAIK, You can create a DependencyProperty of any type. Just change the Type of List<textblock> to List<string>

Abhishek Sur
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wpfcomputer11-Sep-10 11:26

wpfcomputer

11-Sep-10 11:26

The problem is that when I set the dependencyProperty on XAML I do something like:

<br />
     <MyControlsNameSpace:MyControl.MyItems> <br><br />
                <TextBlock Text="First Item" /> <br><br />
                <TextBlock Text="Second Item" /> <br><br />
     </MyControlsNameSpace:MyControl.MyItems><br />

But if I have a List of string I don't know How to set this property

Thanks

Abhishek Sur12-Sep-10 1:50

Abhishek Sur

12-Sep-10 1:50

Well my friend, why don't you use ItemsControl in this regard.

You can go for ListBox.

<ListBox ItemsSource="{Binding}" DataContext="{StaticResource MyItems}">
<ListBox.ItemTemplate>
<DataTemplate> 
<TextBlock Text="{Binding MyProperty}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

If you are using List of STRING you dont need to specify property name. Use Text="{Binding}" which will eventually call ToString for the string object and get the value of it.

Abhishek Sur
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wpfcomputer13-Sep-10 12:35

wpfcomputer

13-Sep-10 12:35

Hello

I'm not so good in wpf.
If I understand well you say that I have to change my property type to ItemsControl intead of String and add a ListBox with that XAML on my custom control.
Is it correct?

How to implement RTL/LTR button in RichEditBox?

Abhishek Sur13-Sep-10 12:54

Abhishek Sur

13-Sep-10 12:54

Yes you are in right path.

Abhishek Sur
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Yariv10-Sep-10 20:16

Yariv

10-Sep-10 20:16

Hi,

I would like to add to my RichEditBox's ToolBar buttons that can switch language (and change direction), like in Word (maybe it is supported only with bi-language windows).
This feature is supported automatically by RichEditBox (and EditBox) and if I use the Alt+Shift I can switch language without any problem, question is how to implement a button that do this?
Logically I think there should have been an EditingCommand for this operation, but I couldn't find one.
Any idea (or better, sample code)?

Thanks,
Yariv

Here is an image showing the buttons I'm talking about:Image

Synchronization

arkiboys10-Sep-10 18:36

arkiboys

10-Sep-10 18:36

Hello,
My application connects to sql server database and displays data...
In some of the tables in sql server, the data can be updated via other applications in the company...
In my silvelight application, how is it possible to update the UI controls everytime the data in the database is changed?
I guess I am after some kind of synchronization between the UI and the data on the database.
Any thoughts please?
Thanks

Re: Synchronization

Abhinav S10-Sep-10 18:44

How to detect the pressed key?

10-Sep-10 18:44

You need to periodically calling the service to check if data has changed and then update the UI (that should happen automatically provided INotify and Data binding have been properly implemented).

Another approach could be to use the Silverlight duplex communication channel[^]. This allows the service to tell the UI that something has changed and the UI needs to be refreshed.

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dbrenth10-Sep-10 9:26

dbrenth

10-Sep-10 9:26

I am in Silverlight and I want to determine which key was pressed by the user - and potentially refuse it.

The keydown event returns two events that seem to be useless. The Key property is missing most punctuation marks. The PlatformKeyCode only gives good character codes for capital letters and numbers. Punctuation and the 10-key pad don't work.

I've also tried the TextInput events. These do let you see the text of the key that was pressed, but it seems that by the time these events are called, it is too late to cancel the key stroke.

Have I missed something? or is just one of those things that can't be done in Silverlight?

Brent

Brent

Abhinav S10-Sep-10 18:40

10-Sep-10 18:40

Try KeyUp.

Purely my observation , but it works better than KeyDown in many cases.

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dbrenth13-Sep-10 3:32

dbrenth

13-Sep-10 3:32

KeyUp is essentially identical to KeyDown except for when the event is triggered. There is still no way to tell that the user pressed the period, question mark, etc. keys.

Brent

Abhinav S13-Sep-10 5:04

13-Sep-10 5:04

Can this [^]thread be of any assistance to you?

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