Develop Reference

MediaElement XAML -> AutoPlay not a property?

I have created a MediaElement in XAML and assigned a .mpg as the source.
Looking at the XAML controls gallery from Microsoft, there are some examples such as:
<MediaPlayerElement Source="Assets/SampleMedia/fishes.wmv"
MaxWidth="400"
AutoPlay="True" />
However, I am faced with invalid markup that is returning:
The property AutoPlay was not found in type MediaElement
I have tried removing the AutoPlay and using a MediaOpened event to start the video from code behind,but there is never any trigger even?
I am not having too much success.
DO I need to add any additional resources to access certain properties?
<MediaElement x:Name="backdropMotion" Source="Images/inMotion_video.mpg"
Stretch="Fill" Margin="198,126,-326,229" Grid.Column="2"
LoadedBehavior="Play" IsEnabled="True" IsMuted="True"
Grid.Row="1" Grid.ColumnSpan="2" MediaOpened="MediaOpenedEvent"
AutoPlay="True"
>
Ultimately, I am trying to run a media element to a panel that effectively acts as an animated background, looping almost like a .gif. First step is to get the element running.

WPF MVVM Chartplotter: Dynamically bind multiple Lines

I'm trying to make the WPF Chartplotter work with some WPF MVVM. As a target of my interest I've chosen our TeamCity Tests Performance. The current Plotter is looking like this:
<dd:ChartPlotter Grid.Row="1">
<dd:ChartPlotter.HorizontalAxis>
<dd:HorizontalIntegerAxis />
</dd:ChartPlotter.HorizontalAxis>
<dd:ChartPlotter.VerticalAxis>
<dd:VerticalIntegerAxis/>
</dd:ChartPlotter.VerticalAxis>
<dd:VerticalAxisTitle Content="Performance in Minutes" FontSize="10" />
<dd:HorizontalAxisTitle Content="Build by ID" FontSize="10" />
<dd:LineGraph DataSource="{Binding TestRunsPerformance, IsAsync=True}" Stroke="Green" StrokeThickness="2">
<dd:LineGraph.Description>
<dd:PenDescription DescriptionString="Test" />
</dd:LineGraph.Description>
</dd:LineGraph>
<dd:LineGraph DataSource="{Binding TestSlowRunsPerformance, IsAsync=True}" Stroke="Red" StrokeThickness="2">
<dd:LineGraph.Description>
<dd:PenDescription DescriptionString="TestSlow" />
</dd:LineGraph.Description>
</dd:LineGraph>
</dd:ChartPlotter>
</Grid>
So I have basically two Test-Categories and for each I show a LineGraph in the Plotter, which I bind to the EnumerableDataSource in the ViewModel. Unfortunately I couldn't test it, but I'm certain it will work this way, since one LineGraph did work so far.
This is cool, but now I would like to make a second Chart with the Unit-Tests with the highest influence. But for this, I can't just create LineGraphs in the XAML and bind, but I would need something like a LineGraph Collection and set an amount of LineGraphs dynamically. Since I'm also learning MVVM, it would be troublesome If I'd really need to do this in the Code behind.
Unfortunately, all the Examples I found so far do exactly this, for example: Dynamic Line chart in C# WPF Application
I found also examples to make this work for Canvas: Is it possible to bind a Canvas's Children property in XAML? but these are UIElements, not PlotterElements.
Is what I'm trying even possible or am I doing something fundamentally wrong?

how to clear image control from local path

i have a image control in wpf like this
<Image x:Name="Img" Source="{Binding IsAsync=True}" />
i set the image by fetching from a url like this
Img.DataContext = ImageUrl;
it shows fine and when i want to clear it i just use
Img.DataContext=null;
for the same control i have a browse button as well to select the image from local path like this
BitmapImage image = new BitmapImage(new Uri(path));
Img.Source=image;
now i want to clear that as well so i do
Img.Source=null;
after that the control wont show the image from url only local images can be opened
Edit: probably i need to set the binding again after making source to null, not sure how to do that

You are abusing bindings horribly. Please stop.
<Image x:Name="Img" Source="{Binding IsAsync=True}" />
Says "Bind to the data context", which isn't all that great. Bind to a property of your view model, something like:
<Image x:Name="Img" Source="{Binding Path=ImageLocation, IsAsync=True}" />
And then only ever change the image using ImageLocation. At the very least, only set it via the DataContext.
Once you set the source to a binding, you should never be changing it via code-behind. Period. Do that, and your problem will "magically" disappear, as you are doing it the right way now.

To clear image control, clear image url.
e.g imgControlName.ImageUrl = "";

WP7 App: Too large page

I have created a small WP7 app which contains one page which is dynamically filled with content. But it goes out of viewable area. Emulator doesn't scroll the page when I click-hold-move on the screen. How do I make it scroll when needed?

One simple option is to drop the content you require inside a ScrollViewer, so for example adding a large TextBlock as so:
<ScrollViewer Name="scrollViewer" ScrollViewer.HorizontalScrollBarVisibility="Visible" >
<TextBlock Height="30" Name="textBlock" FontSize="24"
Text="This is a long block of text which wont fit in the available area" />
</ScrollViewer>
Obviously, in most cases you will want to drop a container control such as Grid or StackPanel into the ScrollViewer and place all your other controls in there.
That said, I'm wondering if you are actually looking for some of the standard WP7 Metro look and feel controls such as the Panorama and Pivot Controls which are available in the latest dev tools - follow that link for full details.

OnScreen event in wpf

I have a small custom control which downloads & displays a contacts image. It ensures that only 1 image is being downloaded at a time by adding itself to a static queue of images awaiting to be downloaded.
It is possible to get quite long contact lists. So I want it to only enter the download queue when it actually becomes visible on the screen (there's a default image).
I've tried placing the logic in the Loaded event, overriding OnRender and the IsVisibleChanged event, but none seem to give me what I want.
any suggestions?
D.R
Edit:
This is a WPF Application, sorry for not mentioning before...

Some system controls (like ListView) have property "VirtualMode" if you set it to true and handle RetrieveVirtualItem event. This event invokes for items which are visible currently and you have to fill those items with data(images) you want. So that you don't need to fill all items at once.

Have you considered using a PriorityBinding in order to provide that functionality?
<DataTemplate DataType="{x:Type vm:MyViewModel}">
<StackPanel Orientation="Horizontal">
<Image>
<Image.Source>
<PriorityBinding FallbackValue="{StaticResource ImgDownloading}">
<Binding Path="ImageSource" IsAsync="True" />
</PriorityBinding>
</Image.Source>
</Image>
<Label Content="{Binding Name}" />
</StackPanel>
</DataTemplate>