I have a multilanguage application and I'm trying to set as Fallbackvalue a Dynamic resource in this way:
<TextBlock Text="{Binding SomeProperty, FallbackValue='{DynamicResource somekEY}'" />
this will throw an exception:
You can set 'DynamicResourceExtension' for the 'StringFormat' type 'Binding' property. You can set 'DynamicResourceExtension' only for a DependencyProperty of a DependencyObject.
how can handle this situation?
The issue is that DynamicResource works like a binding. You can't bind properties of Binding itself (or anything that isn't a DependecyProperty as stated in the error message). You actually see the same sort of error message when you try to do that with a binding: (e.g. {Binding SomeProperty, FallbackValue={Binding SomeOtherProperty}})
This is where PriorityBinding comes in. It allows specifying a series of fallback values as bindings themselves. With PriorityBinding you specify a list of Bindings, the first binding with a valid value is the one used. Ideally we could write something like this:
<TextBlock>
<TextBlock.Text>
<PriorityBinding>
<Binding Path="SomeProperty" />
<DynamicResource ResourceKey="somekEY" />
</PriorityBinding>
</TextBlock.Text>
</TextBlock>
Unfortunately, DynamicResourceExtension can't directly be converted to a binding to be used in a PriorityBinding (or MultiBinding) like the above, so we'll have to use a little trick instead (the example above won't work). We'll use the Tag property (which is a property that has no effect and is basically for holding values for tricks like this) to capture the value of the DynamicResource, and then use a RelativeSource binding in the PriorityBinding to get it:
<TextBlock Tag="{DynamicResource somekEY}">
<TextBlock.Text>
<PriorityBinding>
<Binding Path="SomeProperty" />
<Binding Path="Tag" RelativeSource="{RelativeSource Mode=Self}" />
</PriorityBinding>
</TextBlock.Text>
</TextBlock>
Related
I have created an AttachedProperty that has a PropertyChangedCallback function, which does some formatting to a TextBlock. But to perform the formatting, the Tag attribute is needed. The Tag itself is bound to the output of a Multiconverter.
But my problem is, that the FNamePropertChangedCallback is executed before the Tag is bound to the output of the Multibinding. Thus Tag still Null, when FNamePropertyChangedCallback is triggered.
Is there any way to influence the order in which the Attributes are bound?
I need to bind Tag before binding FInlineProperty.
public static readonly DependencyProperty FInlinePropertyProperty =
DependencyProperty.RegisterAttached("FInlineProperty", typeof(string), typeof(MainWindow),
new PropertyMetadata(null, FNamePropertyChangedCallback));
<TextBlock local:MainWindow.FInlineProperty="{Binding Name}" TextWrapping="WrapWithOverflow">
<TextBlock.Tag>
<MultiBinding Converter="{StaticResource TupleConverter}">
<Binding />
<Binding ElementName="Window"/>
</MultiBinding>
</TextBlock.Tag>
</TextBlock>
Btw: Does someone know how to write local:MainWindow.FInlineProperty="{Binding Name}" in long form? I tried <TextBlock.local:MainWindow.FInlinse>...</TextBlock.local:MainWindow.FInlinse>, but the compiler complains about it.
Update 25.Feb.2017:
I did what you suggested and bound everything to my Attached Property.
<TextBlock TextWrapping="WrapWithOverflow" >
<local:MainWindow.FInlineProperty>
<MultiBinding Converter="{StaticResource GroupConverter}">
<Binding />
<Binding ElementName="Window" Path="MySetup" />
</MultiBinding>
</local:MainWindow.FInlineProperty>
</TextBlock>
The problem with this is, that it is working the first time when the ListBoxItem is created. But updating properties from MySetup does not re-trigger FNamePropertyChangedCallback.
MySetup.ColorString = "green"; // this does not retrigger the callback
MySetup = MySetup.Copy(); // this does retrigger the callback
So currently only assigning MySetup a new copy of itself (changing the reference) triggers callback function again.
That was the reason, why I bound the name property explicitly.
MySetup.ColorString would trigger, if I bind to it explicitly, but I need to bind to MySetup to have all data, so the question is, how to force the binding to execute again, when the bound object itself (reference) has not changed, but something inside did change?
What you actually want is binding between your AttachedProperty and TextBlock.Tag property, so that AttachedProperty is set when Tag changes. But since you are also binding to Name, so I suggest to use MultiBinding for your AP using Name and Tag bindings, thus not depending upon Tag at all.
Try to set the Tag property before you set the attached property. This means that you should also set the attached property using element syntax:
<TextBlock TextWrapping="WrapWithOverflow">
<TextBlock.Tag>
<MultiBinding Converter="{StaticResource TupleConverter}">
<Binding />
<Binding ElementName="Window"/>
</MultiBinding>
</TextBlock.Tag>
<local:MainWindow.FInlineProperty>
<Binding Path="Name" />
</local:MainWindow.FInlineProperty>
</TextBlock>
I have a custom Button type and i cannot change the code. This Button has an property called MyArguments which accepts a string of semicolon separated values.
I have a bunch of TextBoxes on the screen for the user to enter some information.
<TextBox Name="TestTextBox1" />
<TextBox Name="TestTextBox2" />
<TextBox Name="TestTextBox3" />
I want my Button to take these three values and supply them to the MyArguments string property.
If there was only a single TextBox i could use the StringFormat option like this:
<MyButton MyArguments="{Binding ElementName=TestTextBox1, Path=Text, StringFormat='Arguments;{0}' }/>
However you cannot use multiple controls with StringFormat.
I tried using MultiBinding but the MyArguments property gives an error 'The attachable property 'MyArguments' was not found in type MyButton'.
<MyButton.MyArguments>
<MultiBinding StringFormat="Arguments;{0};{1}">
<Binding ElementName="TestTextBox1" Path="Text" />
<Binding ElementName="TestTextBox2" Path="Text" />
</MultiBinding>
</MyButton.MyArguments>
I need this done in pure XAML. No code behind.
Any ideas?
You forgot to add the namespace prefix (e.g. local) to the property:
<local:MyButton>
<local:MyButton.MyArguments>
<MultiBinding StringFormat="Arguments;{0};{1}">
<Binding ElementName="TestTextBox1" Path="Text" />
<Binding ElementName="TestTextBox2" Path="Text" />
</MultiBinding>
</local:MyButton.MyArguments>
</local:MyButton>
This sounds like the parser cannot associate the element syntax property with your element instance. I.e. it thinks you are defining an attached property even though it is supposed to be an instance property.
e.g.
<ListBox ItemsSource="{Binding Data}">
<ListView.ItemTemplate>
<!-- Template -->
</ListView.ItemTemplate>
<ListBox>
Are you referencing the same type? It also looks odd how you have no prefix on your button, or did someone actually abuse the system and compile the assembly to use the WPF namespace?
So the issue is that when I normally bind a single text item to the Text in a TextBlock, the syntax is as follows:
<TextBlock ... Text="{Binding Attributes[StatusDateTime]}" /> //WORKS GREAT!
Now, background is that the DataContext for this part of the app is the output of a 3rd party API. "Attributes" is a collection of KeyValuePair, which is a property of the parent object. StatusDateTime is the key for the value I am returning. The syntax above works just great! So the object would look something like: theDataContextObject.Attributes[StatusDateTime].
BUT, if I need to combine multiple attributes into one TextBlock that's when things get hairy. I have no idea how to access the key from an actual Binding tag:
<TextBlock Grid.Row="0" Grid.ColumnSpan="3" Style="{StaticResource popupText}">
<TextBlock.Text>
<MultiBinding StringFormat="{}{0} at {1}">
<Binding Path="{Attributes[Type]}"/>
<!--<Binding Path="StatusDateTime" />-->
<Binding Path=Attributes[Type]/>
<Binding Path="Type" ElementName="Attributes"/> //the element has no
//name it's just the datacontext
<Binding Path="[StatusDateTime]" />
<Binding Path="Attributes[StatusDateTime]"/>
</MultiBinding>
</TextBlock.Text>
I know the number of examples above does not match the stringformat, I was just pasting examples of my guesses into the multibinding of how to get these values bound.
Apologies if this is a duplicate with another question. I am not sure what to even call this kind of binding where I'm just passing Attributes[StatusDateTime] directly to binding. Keep in mind that Attributes is not the name of an object, it's a property of the object passed to datacontext of the TextBlock's parent control.
So how do I bind to the value of key in the KeyValuePair collection when i have to use a Binding tag inside a MultiBinding?
I have this code :
<Label>
<Label.Content>
<TextBlock>
<TextBlock.Text>
<MultiBinding StringFormat="{} created on {0} by">
<Binding Path="CreationDate" StringFormat="{}{0:dd/MM/yyyy}" />
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</LabeledLabel.Content>
</Label>
OUTPUT
I always get this created on 21/09/2014 00:00:00 by
I tried StringFormat="d", but it didn't work too.
What's the problem with my code ?
You've only got one Binding Path, so you'll only ever get the date and time. Basically, you need to add a Binding element for your person data type. It should be more like this:
<Label>
<Label.Content>
<TextBlock>
<TextBlock.Text>
<MultiBinding StringFormat="{} created on {0:dd/MM/yyyy} by {1}">
<Binding Path="CreationDate" />
<Binding Path="SomeEmployeeObject.Name" />
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</LabeledLabel.Content>
</Label>
Note that you can also set the DateTime StringFormat using the MultiBinding.StringFormat property, instead of adding another on the first Binding object. You also needed to add the {1} to the end of the MultiBinding.StringFormat so that it would output the second (person related) value.
Please see the MultiBinding Class page on MSDN for further information.
UPDATE >>>
I don't understand why putting the StringFormat property on the MultiBinding element has a different behaviour compared to the first element
It doesn't... I could have left it there, but I moved it because you were already using a StringFormat. Using StringFormat property on a MultiBinding is virtually the same as using the string.Format method. Using the method, this is equivalent to what you had in your XAML:
string.Format("created on {0:dd/MM/yyyy} by ", someDate);
And this is equivalent to what I put in your XAML:
string.Format("created on {0:dd/MM/yyyy} by {1}", someDate, someEmployee.Name);
Hopefully, you can now see the difference.
There is a concept of Multibinding in WPF, which is really useful if we want to bind some UI Control that depends on multiple values, like in this one.
I am trying to do the same with ProgressBar, like I am using ProgressBar to display how much storage is used by the users and it depends on two properties.
UsedStorage
TotalStorage
After searching, i could not find a way to bind Value property of ProgressBar with multiple properties and custom convertor.
Something like (Just a concept)
<ProgressBar Width="172" Height="16" >
<ProgressBar.Value>
<MultiBinding Converter="{StaticResource myConverter}">
<Binding Path="UsedStorage" RelativeSource="{RelativeSource AncestorType={x:Type Window}}"/>
<Binding Path="TotalStorage" RelativeSource="{RelativeSource AncestorType={x:Type Window}}"/>
</MultiBinding>
</ProgressBar.Value>
</ProgressBar>
But problem is there is nothing like MultiBinding under ProgressBar.Value. So the question is,
Is there a way to MultiBind ProgressBar Value?
Even though the Visual Studio intellisense might not show that, it is perfectly valid.
However, Using RelativeSource TemplatedParent only works inside a ControlTemplate. It is unclear to me where are you trying to get your values from.