WPF Discussion Boards

Re: Databinding a ListBox using MVVM light (Windows Phone)

19-May-13 14:51

Set the items source property of the listbox to your list ("theList") not the items source property of item template.

XML

<ListBox x:Name="myListBox" HorizontalAlignment="Left" Height="100" ItemsSource="{Binding theList}" VerticalAlignment="Top" Width="200">

jockey4her19-May-13 15:42

jockey4her

19-May-13 15:42

Thanks Amitosh, but I think there must be more to it.

I still don't see any data from the ViewModel with an additional ItemsSource={"Binding theList"} on the listbox declaration.

Maybe this is useful: I pulled a reference to the ViewModel in the code behind. I manually assigned myListBox.ItemsSource=vm.theList, and the data appeared!

As to why the one bound through MVVM doesn't work, still a mystery.

modified 19-May-13 21:55pm.

Re: Databinding a ListBox using MVVM light (Windows Phone)

AlphaDeltaTheta19-May-13 16:08

Re: Databinding a ListBox using MVVM light (Windows Phone)

19-May-13 16:08

I agree, I took me a week to understand MVVM architecture, yet not perfectly. I still get weird errors! Confused | :confused:

Where did you initialize the view model in the code behind or xaml?
Viewmodel should be set as the data context of the root element (window,page,usercontrol... etc).

jockey4her19-May-13 17:07

jockey4her

19-May-13 17:07

Thanks Amitosh, yeah I agree with you. Not obvious how it works.

Here is the complete code. It is the default project that the template generates.
You can see my test case in the code behind. When I run it, I only see the data from the code
behind, not the view model.

XAML
http://pastebin.com/n6LbfAdk[^]

VIEWMODEL.cs
http://pastebin.com/uvh2sNv9[^]

MAINPAGE.cs
http://pastebin.com/dQadjL7T[^]

Re: Databinding a ListBox using MVVM light (Windows Phone)

AlphaDeltaTheta20-May-13 15:08

WPF datagrid text alignment in columns

20-May-13 15:08

Ok, I had a look into your code...
You have got the following errors

--In MainViewModel.cs--
Line 42,43 - reference to _welcomeTitle. That should be _theText

Line 47,48 - You have used Dictionary. Binding to a Dictionary doesn't update the view if any value is changed. Get a ObservableDictionary. Unfortunately C# doesn't have such functionality, so google for it.

Line 49,50 - You have used List, Binding to a List doesn't update the view if any value is changed. Use ObservableCollection. It's part of System.Collections.ObjectModel
-----------------------

Now remove all code-behind and see if it works. Also remove the ItemsSource property of the ItemsControl at Line 50. MainPage.xaml

Please consider: Is it necessary to use a dictionary?? It is difficult to bind to a dictionary, you might have possible errors ahead!!

Good Luck!

elelont216-May-13 23:53

elelont2

16-May-13 23:53

Hi,
i have a datagrid implemented in xaml like this:

HTML

<DataGrid ItemsSource="{Binding Stuff}" HeadersVisibility="None" GridLinesVisibility="None" AutoGenerateColumns="True" Height="500" Margin="72,363,72,-3" Name="myGrid" VerticalAlignment="Top" Background="{x:Null}" RowBackground="{x:Null}" CanUserAddRows="True" FontSize="20" /><pre lang="xml">

The grid is automatically populated (via a Binding) with two columns and some data. All is well but the text in the columns is left-aligned.

Is it possible to force the text in one of the autogenerated columns to be right-aligned?

Regards

Re: WPF datagrid text alignment in columns

Pete O'Hanlon17-May-13 0:33

Pete O'Hanlon

17-May-13 0:33

You should be able to do this by applying a style to the DataGridColumnHeader. Off the top of my head, the following should do it:

XML

<Style TargetType="{x:Type DataGridColumnHeader}">
  <Setter Property="ContentTemplate">
    <Setter.Value>
      <DataTemplate>
        <TextBlock Text="{Binding}" HorizontalAlignment="Right" />
      </DataTemplate>
    </Setter.Value>
  </Setter>
</Style>

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Re: WPF datagrid text alignment in columns

elelont217-May-13 2:16

elelont2

17-May-13 2:16

Hi and thanks for the reply.

Unfortunately that did not do the trick. The column headers are hidden so i do not need to right-align them.

Basically the datagrid has two columns of data. I need the DATA in ONE of the columns to be right aligned.

I tried this:

HTML

<Style TargetType="DataGrid">
       <Setter Property="CellStyle">
           <Setter.Value>
               <Style TargetType="DataGridCell">
                   <Setter Property="HorizontalAlignment" Value="Right"/>
               </Style>
           </Setter.Value>
       </Setter>
   </Style>

but that just plain righ-aligns everything in the datagrid (data in column 1 and in column 2). Is it possible to apply this to column 2 only?

Note that i do not have the column definitions in my xaml since the datagrid is populated via a binding.

Thanks

Re: WPF datagrid text alignment in columns

Pete O'Hanlon17-May-13 2:31

Pete O'Hanlon

17-May-13 2:31

You can use the AutoGeneratingColumn event to handle this. Source[^].

I was brought up to respect my elders. I don't respect many people nowadays.

CodeStash - Online Snippet Management | My blog | MoXAML PowerToys | Mole 2010 - debugging made easier

New Table to an existing Silverlight project

picasso216-May-13 19:36

picasso2

16-May-13 19:36

I have created a SilverLight application that uses ADO and DomainServices to populate a DataGrid from an SQL 2008 database server. The context looks like this

EcDomainContext context1 = new EcDomainContext();

A few months later, I added a table to the database so in order to use this new table, I had to rebuild as follows:

-deleted all MyDomainServices (.cs) files
-deleted the Mymodel (.edmx) file
-recreate by adding the ADO and Domainservices again
-reconfigure the MyDomainServices.cs as before.

Well, I just added another table and I would like to know if there is an easier way to do this?

Many thanks.
Ps

WPF motion path animation on controls

usmankai16-May-13 14:10

usmankai

16-May-13 14:10

hi i have made the stickin which i am moving a small box around it using motion path. but when i change the angle of that stick through slider, the box movement "animation" still remains same the original path which i set the default. is there any way i can change its animation by depending on its angle.

HTML

Must compile XAML file that specifies events

Neo1010115-May-13 23:29

Neo10101

15-May-13 23:29

When working with a XAML file in conjunction with JavaScript and HTML in VisualStudio, whenever I try to set the Loaded attribute in my Grid, my XAML page will fail to load. I get a blank screen and when I right click somewhere in the page, I see a little box saying 'Silverlight'. The JavaScript will also fail to execute.

I get the following message when I try to open the page in Internet Explorer: "Must compile XAML that specifies events".

Surprisingly, the other XAML page (Speeds.xaml) I have does not fail to execute the JS nor the XAML. It runs properly.

Failing XAML file (Accuracy.xaml):

XML

<?xml version="1.0" encoding="UTF-8"?>
<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      
      Loaded="onLoaded">
  <Grid.RowDefinitions>
    <RowDefinition Height="20*" />
    <RowDefinition Height="60*" />
    <RowDefinition Height="20*" />
  </Grid.RowDefinitions>
  <Grid.ColumnDefinitions>
    <ColumnDefinition Width="20*" />
    <ColumnDefinition Width="60*" />
    <ColumnDefinition Width="20*" />
  </Grid.ColumnDefinitions>
  <Grid.Background>
    <LinearGradientBrush>
      <GradientStop Color="#FF3B596E" />
      <GradientStop Color="#FF93C5E8" Offset="1" />
    </LinearGradientBrush>
  </Grid.Background>
  <Canvas Grid.Row="1" Grid.Column="1">
    <Canvas.Background>
      <LinearGradientBrush>
        <GradientStop Color="#FF93C5E8" />
        <GradientStop Color="#FF3B596E" Offset="1" />
      </LinearGradientBrush>
    </Canvas.Background>
    <TextBlock Foreground="Ivory" FontSize="16" Canvas.Left="369.68" Canvas.Top="22.29017076">Accuracy</TextBlock>
    
    <Border Width="103.03999999999999" Canvas.Left="103.03999999999999" Canvas.Top="75.76162307999999" BorderThickness="2" BorderBrush="Red" Height="26.73572616">
      <TextBlock Text="Sum 1-20" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Center" />
    </Border>
    <Border Width="103.03999999999999" Canvas.Left="357.6" Canvas.Top="75.76162307999999" BorderThickness="2" BorderBrush="Red" Height="26.73572616">
      <TextBlock Text="Sum 21-40" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Center" />
    </Border>
    <Border Width="103.03999999999999" Canvas.Left="612.1600000000001" Canvas.Top="75.76162307999999" BorderThickness="2" BorderBrush="Red" Height="26.73572616">
      <TextBlock Text="Sum 41-60" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Center" />
    </Border>
    <Line X1="48.480000000000004" Y1="154.9844" X2="758.24" Y2="154.9844" StrokeThickness="2" Stroke="Red" />
    <Line X1="48.480000000000004" Y1="154.9844" X2="48.480000000000004" Y2="333.6304" StrokeThickness="2" Stroke="Red" />
    <Line X1="48.480000000000004" Y1="200.5612596" X2="758.24" Y2="200.5612596" StrokeThickness="1" Stroke="Red" />
    <Line X1="48.480000000000004" Y1="245.1381192" X2="758.24" Y2="245.1381192" StrokeThickness="1" Stroke="Red" />
    <Line X1="48.480000000000004" Y1="289.7149788" X2="758.24" Y2="289.7149788" StrokeThickness="1" Stroke="Red" />
    <Line X1="48.480000000000004" Y1="334.29183839999996" X2="758.24" Y2="334.29183839999996" StrokeThickness="1" Stroke="Red" />
    <Border Canvas.Left="24.240000000000002" Canvas.Top="148.42759999999998" Width="15" HorizontalAlignment="Center">
      <TextBlock Text="0" Foreground="Ivory" HorizontalAlignment="Center" />
    </Border>
    <Border Canvas.Left="24.240000000000002" Canvas.Top="193.0044596" Width="15" HorizontalAlignment="Center">
      <TextBlock Text="5" Foreground="Ivory" HorizontalAlignment="Center" />
    </Border>
    <Border Canvas.Left="24.240000000000002" Canvas.Top="237.5813192" Width="15" HorizontalAlignment="Center">
      <TextBlock Text="10" Foreground="Ivory" HorizontalAlignment="Center" />
    </Border>
    <Border Canvas.Left="24.240000000000002" Canvas.Top="282.1581788" Width="15" HorizontalAlignment="Center">
      <TextBlock Text="15" Foreground="Ivory" HorizontalAlignment="Center" />
    </Border>
    <Border Canvas.Left="24.240000000000002" Canvas.Top="326.73503839999995" Width="15" HorizontalAlignment="Center">
      <TextBlock Text="20" Foreground="Ivory" HorizontalAlignment="Center" />
    </Border>
    <Border Canvas.Left="96.88" Canvas.Top="154.9844" Border.Background="#FF0093DD" Width="30.320000000000004" Height="116.1199" Visibility="Collapsed" x:Name="bar0" MouseLeftButtonUp="test">
      <TextBlock Text="13" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
    </Border>
        <Border Canvas.Left="145.35999999999999" Canvas.Top="154.9844" Border.Background="#FF29166F" Width="30.320000000000004" Height="35.7292" Visibility="Collapsed" x:Name="bar1" MouseLeftButtonUp="test">
      <TextBlock Text="4" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
    </Border>
        <Border Canvas.Left="193.84" Canvas.Top="154.9844" Border.Background="#FF830F0F" Width="30.320000000000004" Height="26.7969" Visibility="Collapsed" x:Name="bar2" MouseLeftButtonUp="test">
      <TextBlock Text="3" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
    </Border>
        <Border Canvas.Left="345.36" Canvas.Top="154.9844" Border.Background="#FF0093DD" Width="30.320000000000004" Height="53.5938" Visibility="Collapsed" x:Name="bar3" MouseLeftButtonUp="test">
      <TextBlock Text="6" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
    </Border>
        <Border Canvas.Left="393.84000000000003" Canvas.Top="154.9844" Border.Background="#FF29166F" Width="30.320000000000004" Height="80.3907" Visibility="Collapsed" x:Name="bar4" MouseLeftButtonUp="test">
      <TextBlock Text="9" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
    </Border>
        <Border Canvas.Left="442.32" Canvas.Top="154.9844" Border.Background="#FF830F0F" Width="30.320000000000004" Height="44.6615" Visibility="Collapsed" x:Name="bar5" MouseLeftButtonUp="test">
      <TextBlock Text="5" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
    </Border>
        <Border Canvas.Left="593.84" Canvas.Top="154.9844" Border.Background="#FF0093DD" Width="30.320000000000004" Height="107.1876" Visibility="Collapsed" x:Name="bar6" MouseLeftButtonUp="test">
      <TextBlock Text="12" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
    </Border>
        <Border Canvas.Left="642.32" Canvas.Top="154.9844" Border.Background="#FF29166F" Width="30.320000000000004" Height="26.7969" Visibility="Collapsed" x:Name="bar7" MouseLeftButtonUp="test">
      <TextBlock Text="3" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
    </Border>
        <Border Canvas.Left="690.8000000000001" Canvas.Top="154.9844" Border.Background="#FF830F0F" Width="30.320000000000004" Height="44.6615" Visibility="Collapsed" x:Name="bar8" MouseLeftButtonUp="test">
      <TextBlock Text="5" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
    </Border>
    <Border Canvas.Left="96.96000000000001" Canvas.Top="378.87690204" Border.Background="#FF0093DD" Width="200.0" Height="31.19970204">
      <TextBlock Text="N° of correct responses" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Center" />
    </Border>
    <Border Canvas.Left="296.96000000000004" Canvas.Top="378.87690204" Border.Background="#FF29166F" Width="200.0" Height="31.19970204">
      <TextBlock Text="N° of incorrect responses" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Center" />
    </Border>
    <Border Canvas.Left="496.96000000000004" Canvas.Top="378.87690204" Border.Background="#FF830F0F" Width="200.0" Height="31.19970204">
      <TextBlock Text="N° of no responses" Foreground="Ivory" HorizontalAlignment="Center" VerticalAlignment="Center" />
    </Border>
  </Canvas>
</Grid>

Working XAML (Speeds.xaml):

XML

<?xml version="1.0" encoding="UTF-8"?>
<Grid
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    Loaded="onLoaded">
</Grid>

Why is this happening and how can I fix this?

modified 16-May-13 5:42am.

Re: Must compile XAML file that specifies events

AlphaDeltaTheta18-May-13 16:42

Re: Must compile XAML file that specifies events

18-May-13 16:42

Yes you have the answer, you must compile XAML to BAML in order to use events!
This is what that is done while compiling an app in visual studio. I guess you are trying with an XAML browser project??

Neo1010119-May-13 4:23

Neo10101

19-May-13 4:23

No, I do not have the answer. The problem is not 'Must compile XAML that specifies events'.

The problem is that Visual Studio does not accept XAML files that have Elements whose Background property is set. On my machine it is not compatible with the Background property for some reason. After I set any Background property on my XAML page and I run my project, Visual Studio will show a white page in my Accuracy.html. Everything is white. No content. I am trying to understand why Visual Studio does not accept this Background property.

Re: Must compile XAML file that specifies events

AlphaDeltaTheta19-May-13 14:48

Is Frame is a good Control for loading a Xaml page in WPF?

19-May-13 14:48

Strange?? I do files with a great deal of backgrounds with fancy gradients, images... designed with blend of course??
Well mine is vs2012? yours??

Mohammed Hameed14-May-13 19:53

Mohammed Hameed

14-May-13 19:53

Hi,
Is this okay to use Frame control in my Main window to load a Xaml page at Runtime?
It also has to support drag/drop feature so that users can drag a control from Toolbox of Main window to the Xaml page in the Frame.

Please suggest/explain.

Thanks.

Be a good professional who shares programming secrets with others.

Re: Is Frame is a good Control for loading a Xaml page in WPF?

Abhinav S15-May-13 8:12

Abhinav S

15-May-13 8:12

You can directly load the view into the user control.

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Re: Is Frame is a good Control for loading a Xaml page in WPF?

Mohammed Hameed15-May-13 19:28

Mohammed Hameed

15-May-13 19:28

Whether user control supports drag/drop?

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TreeViewDragDropTarget Drag Certain Node Only

Member 1003315714-May-13 19:52

Member 10033157

14-May-13 19:52

Hi, I have a treeview where the nodes are generated on runtime.

I want to drag the child node into a canvas a generate an image for each node.

My scenario is i want to allow only certain node to be able to drag and only allow dragging when user want to edit the canvas. How should i achieve that?

Currently I'm using the Silverlight Toolkit TreeViewDragDropTarget.

WPF / MVVM Get Data From ViewModel

Kevin Marois14-May-13 15:10

14-May-13 15:10

I have been working on a project that uses user controls inside other views. What I still can't figure out is how to get a reference to the user control's ViewModel so I can get data off of it or write data to it.

So far, I have been getting a reference to the user control, then getting the VM as the DataContext, then accessing it through that refereence. But this doesn't seem to be right.

In another project I'm using a factory pattern in my AppResources.XAML, such as:

<DataTemplate DataType="{x:Type vm:ClientCenterViewModel}">
    <vw:ClientCenterView/>
</DataTemplate>

This does a nice job of pairing the VM to the View, but I can't get a reference to the view's VM to read/write to it.

What's the right way to do this?

Thanks

If it's not broken, fix it until it is

SledgeHammer0115-May-13 6:57

SledgeHammer01

15-May-13 6:57

You shouldn't need to have access to a child controls VM directly. It's all done via data binding.

<Window>
<Grid>
<MyChildView SomeProp="{Binding SomeProp}" />
</Grid>
</Window>

If you are using DataTemplates to map views <-> VMs, you also don't need access to the VM directly because those views should operate on thier own VMs which would talk to the persistance layer directly.

If you are finding that you need to access a child control/view to do stuff from the code behind, its probably because you didn't expose that functionality with a bindable property. If you don't own the code of the child view, you can expose the functionality you need with a bindable attached behavior.

Kevin Marois15-May-13 7:54

15-May-13 7:54

Ok, I'm not sure I understand.

In this case I have a Materials view, and on it is a control that lists prices. The prices control is used in more than one view which is why it's a control.

There is a one to many between Materials and Prices, so the prices view needs to know the PK of the Material. In addition, the Material needs to know the count of Prices and other info.

When a material is selected I need to tell the prices view the PK of the selected material so it can load them. When a price is added to the list in the Prices control, the Material view needs to know it.

The Prices control already handles it's own CRUD operations, but I don't understand how it and the Materials view are supposed to intertact. There has to be some way to say "Hey Prices view, give me your data" or, "Hey Prices view, load the prices for this Material".

Using Data Templates to map them seems to make it impossible since the VM for the Materials has no clue that there's a Prices control any where.

If it's not broken, fix it until it is

SledgeHammer0115-May-13 8:41

SledgeHammer01

15-May-13 8:41

Yeah, so its like what I said. Assuming I get what you are talking about Smile | :)

. Psuedo-code:

<Window>
<MaterialView />
</Window>

<MaterialView>
<ListView Name="lv" ItemsSource="{Binding ListOfMaterials}" />
<PriceControl Source="{Binding ElementName=lv, Path=SelectedItem.PK}" />
</MaterialView>

Then your PriceControl would auto-magically know when a different material has been selected. But it needs to expose a property that can be data-bound.

EDIT: I just noticed in your response that you wanted to go both ways, so you can do something like:

<MaterialView>
<Label Content="{Binding ElementName=pc, Path=Count" />
</MaterialView>

You just need to expose everything you want to transfer back and forth as a property in the VMs.

The key here is to use the ElementName binding.

Kevin Marois15-May-13 9:00

15-May-13 9:00

I see. Thanks!

If it's not broken, fix it until it is

Kevin Marois20-May-13 14:00