From a control in a WPF XAML view, I need to access the properties of another control that I can reach in the Visual Tree only when walking up to a common parent control and then down from there.
As an example:
<PageUserControl>
<Grid>
<TextBlock Text="Some example text" />
</Grid>
<TextBlock Text="{Binding Source={RelativeSource Mode=FindAncestor, AncestorType=PageUserControl, Path=??? I want to access the TextBlock}" />
</PageUserControl>
I want to access the text property of the first text block from the second text block (this is just an example).
What I would need is a way to combine relative sources, first one to go up the visual tree and find the PageUserControl, second one to go down the visual tree from there and find the grid and then finally a third one to find the text block within the grid.
Am I missing something here or is it just not possible?
I cannot add control IDs or something like this, it has to work with control types only.
I was thinking about something like a relative source that takes a XPath syntax, but it seems as if this was meant for another purpose (binding XML documents).
Maybe another idea?
Thank you!
I found a solution for my problem. It is possible using this approach:
<PageUserControl>
<Grid>
<TextBlock Text="Some example text" />
</Grid>
<TextBlock Text="{Binding Path=Children[0].Children[0].Text,
RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=PageUserControl}}" />
</PageUserControl>
While not very flexible, it is good enough for me.
Related
Sorry for my bad headline but I couldn't figure out a better one. Heck, I don't even know how to properly ask my question. But here it comes.
I have a custom control in WPF, let's call it Cell. This control does have a few dependency properties, one Text to show in the Cell and a few "decorative" properties for background color, foreground color and so on. If I use this Cell control stand-alone, everything works fine so far.
Then I have another custom control inheriting from ItemsControl, let's call it Field. This control should show a text and some Cells. it has some "decorative" properties for the text part as well. The information about showing Cells is given to the control by a DataTemplate, something like
<DataTemplate x:Key="CellTemplate"
DataType="...">
<ns:Cell Text="{Binding Text}"
Background="{Binding ...}" />
</DataTemplate>
...
<ns:Field ItemsSource="{Binding Cells}"
ItemTemplate="{StaticResource CellTemplate}" />
If I use this Field control stand-alone, everything works fine so far.
Now I want to show several Field controls at once. So I put an ItemsControl on my window and gave an ItemTemplate again, something like:
<DataTemplate x:Key="CellTemplate"
DataType="...">
<ns:Cell Text="{Binding Text}"
Background="{Binding ...}" />
</DataTemplate>
<DataTemplate x:Key="FieldTemplate"
DataType="...">
<ns:Field ItemsSource="{Binding Cells}"
ItemTemplate="{StaticResource CellTemplate}"
FieldText="{Binding Text}"
TextBackground="{Binding ...}" />
</DataTemplate>
<ItemsControl ItemsSource="{Binding Fields}"
ItemTemplate="{StaticResource FieldTemplate}" />
As long as I preview my WPF window everything works fine so far. Changing the values of some "decorative" properties at Cell level or at Field level is immediately shown in the preview.
But if I run my program it seems that all "decorative" properties at Cell level are ignored. I can see all my Fields with their respective texts and I can see every Cell in every Field with their respective texts. But all Cells are plain white. All set colors are not shown.
Snoop tells me, that every color is set to Transparent by the ParentTemplate.
Visual Studio doesn't show me any exceptions or any binding errors. So I'm kind of stuck at where or how I can find the error and fix it.
So I wanted to ask you, if you may have a hint for me.
Does this contruction with a DataTemplate containing a DataTemplate and both DataTemplates bind to it's DataContext work?
Or does it have something to do with maybe re-using Brush objects that shouldn't be re-used?
But why is it working in the preview?
This is something that has bothered me for some time, and I'm not sure if it's some setting that can be turned off or not, but whenever I copy and paste something in xaml in VS 2010 it always auto-indents the line that I'm on and often the one after it for some reason. For example, say I have these lines of xaml code:
<TextBlock VerticalAlignment="Top" Foreground="Red" FontSize="11" Width="5"
Text="*" Visibility="{Binding Path=ShowInvalidFlag,UpdateSourceTrigger=PropertyChanged}" />
<TextBlock Width="Auto" Background="Transparent" Text="{Binding Path=QuestionValue}" />
and then I realize that the first TextBlock needs a Margin defined and I copy Margin="0,1,0,0" from another control within the same xaml document and paste it within the declaration of the above TextBlock it auto-indents and I end up with this:
<TextBlock VerticalAlignment="Top" Margin="0,1,0,0" Foreground="Red" FontSize="11" Width="5"
Text="*" Visibility="{Binding Path=ShowInvalidFlag,UpdateSourceTrigger=PropertyChanged}" />
<TextBlock Width="Auto" Background="Transparent" Text="{Binding Path=QuestionValue}" />
Why is it doing this? It doesn't even have to be copied from the same xaml file or even xaml code (I just tried copying random text from a text file and pasted it within the control and it still auto-indented). It's quite frustrating that every time I paste something in xaml I need to re-adjust my indentation.
Converted from comment:
If you search in the options in VS you should be able to find under Text Editor and Xaml an option for Indenting. By default it's set to "smart" which isn't always as smart as you might want it to be. Play around with that and see if it's more comfortable for you. Copy / pasting seems to be particularly prone to tripping it up.
In addition, you can also always so to "Edit" -> "Advanced" and then either "Format Document" or "Format Selection" to force Visual Studio to take another pass at formatting which may either fix, or make worse, your problem.
I think the problem is that it tries to optimize between speed and correctness. When you paste something it may not consider the entire context of where you are pasting and instead only look at the immediate parent and / or siblings which is a problem when you are pasting in a whole bunch of stuff.
I have many FrameworkElements (TextBlock, CheckBox, ListBox..) and I would like to make something allowing me to show a small number besides every one control.
Some text ³
I came with the idea to write a MarkupExtension, where I could write that number like this:
..
<TextBlock Text="Some Text" SomeExtension="3" />
..
and then to add it somehow to the template of the Control.
But I'm sure, you guys have better solution for this problem ;)
One way to go with it would be create a Attached Property. Upon setting it on a control, a custom Adorner would be added for that control showing specified number.
Use the tag property to provide the number you want and inside the custom template databind to the property
<TextBlock Text="Some Text" Tag="3" />
and inside the controltemplate
<TextBlock Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Tag}"/>
I am working with Silverlight 4 and trying to put my test apps multilingual but I am having some trouble when I arrive to the "RichTextBox" control. I am able to bind it properly by doing back-code (c#), but when trying using the "DataContext" attributes I am not able to load it at all.
I have created a FormatConverter that return a Block (paragraph) for testing and my code where I have my RichTextBox looks like:
<RichTextBox x:Name="rtaTest" BorderThickness="0" IsReadOnly="True" UseLayoutRounding="True"
DataContext="{Binding Source={StaticResource Localization}, Path=Home.MainContent, Converter={StaticResource ParagraphFormatConverter}}">
</RichTextBox>
I am wondering if there is a way of binding a RichTextBox from the XAML.
Run seems to support databinding in SL4, as in:
<RichTextBox>
<Paragraph>
<Run Text="{Binding Path=LineFormatted}" />
</Paragraph>
</RichTextBox>
I think you may be a little confused about the used of the DataContext. You might for example have some Rich text where some children of one or more InlineUIContainer elements may retrieve their text from a property of some object. You would assign the object to the DataContext.
Whilst I'm not quite sure what you were expecting to achieve but I suspect that what you really need is for your converter to actually return a BlocksCollection (even if it just contains the single Block you were originaly returning) and then to bind as:-
<RichTextArea x:Name="rtaTest" BorderThickness="0" IsReadOnly="True"
UseLayoutRounding="True"
Blocks="{Binding Source={StaticResource Localization},
Path=Home.MainContent, Converter={StaticResource ParagraphFormatConverter}}" />
This FillFromXml is a WPF thing? Don't see it in Silverlight.
Blocks cannot be set, they can only be fetched. One way to set the blocks for a RichTextArea is
public static void UpdateRichTextArea(RichTextArea area, string xmlText)
{
if (area == null)
return;
area.Blocks.FillFromXml(xmlText, true);
}
I'd like an advice to the following problem: I want to embed a Button into a text flow, but when I embed a Button and Label (or TextBlock) into the WrapPanel, I get the first figure:
alt text http://sklad.tomaskafka.com/files/wpf-wrappanel-problem.png
I think that one of solutions could be FlowDocument, but I feel that this is far too heavy for a control simple like this (which could be used in several hundred instances). Do you have some other ideas about how to implement this? Thank you!
EDIT:
One solution could be the following (I didn't know it was possible to put more stuff into TextBlock), but I would lose the ability to bind (which I need):
<TextBlock TextWrapping="Wrap">
<Span>
<Button x:Name="MyButton" Command="{Binding Path=MyCommand}" Content="+" />
<Run x:Name="MyLabel" Text="{Binding Path=Subject}" />
<!--
Problem: binding makes following error:
A 'Binding' cannot be set on the 'Text' property of type 'Run'.
A 'Binding' can only be set on a DependencyProperty of a DependencyObject.
-->
</Span>
</TextBlock>
To bind to Run.Text, checkout the BindableRun class by Fortes. Simple to implement, I use it all over my projects.
I found that implementing BindableRun correctly is pretty tricky - and almost all other available implementations will cause an exception from wpf layouting engine when the bound content changes from null to something non-null - see this problem, keyword "Collection was modified; enumeration operation may not execute."
Corrrect implementation from Microsoft is here - it shows how tricky this really is.
Solution: BindableRun class + the following markup:
<TextBlock>
<Button x:Name="MyButton" Command="{Binding Path=MyCommand}" Content="+" />
<common:BindableRun x:Name="Subject" BindableText="{Binding Path=Subject}"/>
</TextBlock>
Funny thing it works on the designer of a UserControl...
In that case, using the Property Change of your control to set the value to the Run is enough. I mean, if you had something like:
<TextBlock>
<Run Text="{Binding ElementName=thisCtrl, Path=Description}" />
</TextBlock>
Then just name the run, and on your property change handler of your UserControl DependencyProperty get/set the value.