I'm trying to bind a ComboBox to DataContext.
<ComboBox ItemsSource="{Binding Path=Numbers}"
SelectedValue="{Binding Path=CurrentNumber,Mode=TwoWay}">
</ComboBox>
The above code works, but when I try to change how the items are displayed using a converter implementing IMultiValueConverter and MultiBinding nothing is displayed. I have debugged the method implementing the IMultiValueConverter and it is not getting executed. What could be the problem?
<ComboBox ItemsSource="{Binding Path=Numbers}"
SelectedValue="{Binding Path=CurrentNumber,Mode=TwoWay}">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock>
<TextBlock.Text>
<MultiBinding Converter="{StaticResource MultiUnitConverter}" ConverterParameter="{x:Static enumerations:Quantity.Length}" >
<Binding Path="."/>
<Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type Window}}" Path="DataContext.CurrentUnit"/>
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
Update:
I tried the following instead of the ComboBox, the converter is fired and the data is loaded but not displayed!
<TextBlock>
<TextBlock.Text>
<MultiBinding Converter="{StaticResource MultiUnitConverter}" ConverterParameter="{x:Static enumerations:Quantity.Length}" >
<Binding Path="CurrentNumber"/>
<Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type Window}}" Path="DataContext.CurrentUnit"/>
</MultiBinding>
</TextBlock.Text>
</TextBlock>
The following works though:
<TextBlock>
<TextBlock.Text>
<Binding Path="CurrentNumber"></Binding>
</TextBlock.Text>
</TextBlock>
For all who may get stuck with this in the future and ruin their entire evening here is the solution I found!
It seems adding StringFormat solves the problem!
<ComboBox ItemsSource="{Binding Path=Numbers}" SelectedItem="{Binding Path=Number, Mode=TwoWay}">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock>
<TextBlock.Text>
<MultiBinding
Converter="{StaticResource MultiUnitConverter}"
ConverterParameter="{x:Static enumerations:Quantity.Length}"
StringFormat="{}{0:0.###}">
<Binding Path="."/>
<Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type Window}}" Path="DataContext.CurrentUnit"/>
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
Did you define the converter resource somewhere else in your xaml? If not, you should do so. For instance, if your ComboBox lives in a UserControl you could add:
<UserControl.Resources>
<local:MultiUnitConverter x:Key="multiUnitConverter"/>
</UserControl.Resources>
And of course you would need to update your Converter StaticResource to match the case-sensitive Key above.
Related
How can I use x:Static with a multi binding as below?
<TextBlock.Text>
<MultiBinding StringFormat="{x:Static language:Resource.Message} : {0}">
<Binding Path="NoOfMessages" />
</MultiBinding>
</TextBlock.Text>
There is an error yelling at me with this code.
use multiple inlines:
<TextBlock>
<Run Text="{x:Static language:Resource.Message}"/>
<Run Text=":"/>
<Run Text="{Binding NoOfMessages, Mode=OneWay}"/>
</TextBlock>
As an alternative if you want to rely on MultiBinding and StringFormat:
<TextBlock.Text>
<MultiBinding StringFormat="{}{0} : {1}">
<Binding Source="{x:Static language:Resource.Message}"/>
<Binding Path="NoOfMessages" />
</MultiBinding>
</TextBlock.Text>
Make sure to use the escape sequence {} for the braces.
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When using DisplayMemberPath, it works as expected - it jumps to the typed character, but in the following case i need to concatenate two fields, Surname and Name and would like to jump to the Surname, but it is not working. Anyone knows a solution? Here is the example:
<ComboBox ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.AllDoctors}" SelectedValue="{Binding Path=Doctor.Id}" SelectedValuePath="Id" >
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock>
<TextBlock.Text>
<MultiBinding StringFormat="{}{0} {1}">
<Binding Path="Surname"/>
<Binding Path="Name"/>
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
Add the TextSearch.TextPath attached property to your ComboBox and
set IsTextSearchEnabled to True.
<ComboBox IsTextSearchEnabled="True" TextSearch.TextPath="Surname" ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.AllDoctors}" SelectedValue="{Binding Path=Doctor.Id}" SelectedValuePath="Id" >
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock>
<TextBlock.Text>
<MultiBinding StringFormat="{}{0} {1}">
<Binding Path="Surname"/>
<Binding Path="Name"/>
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
In WPF you can use MultiBinding for normal properties. E.g.:
<TextBlock>
<TextBlock.Text>
<MultiBinding>
...
</MultiBinding>
</TextBlock.Text>
</TextBlock>
How would you do this for an attached property like Canvas.Left?
You can directly do that inline like this:
<TextBlock>
<Canvas.Left>
<MultiBinding>
<Binding Path="ABC"/>
<Binding Path="DEF"/>
</MultiBinding>
</Canvas.Left>
</TextBlock>
I have a ListView in my XAML and I am trying to hook up a MultiBinding Converter.
<ListView
Grid.Column="4"
Grid.Row="1"
Grid.RowSpan="5"
Margin="8,0,8,8"
HorizontalAlignment="Stretch"
Name="lvDisplayType"
ItemsSource="{Binding Path=Types}"
SelectedItem="{Binding Path=Current.Opt}"
VerticalAlignment="Stretch"
SelectionChanged="lvType_SelectionChanged"
SelectionMode="Single"
ScrollViewer.HorizontalScrollBarVisibility="Disabled">
<ListView.ItemTemplate>
<DataTemplate>
<DockPanel
HorizontalAlignment="Center">
<TextBlock
Text="{Binding Path=., Converter={StaticResource DisplayConverter}}"
HorizontalAlignment="Center"
Padding="6"
VerticalAlignment="Center"
TextWrapping="Wrap">
<TextBlock.ToolTip>
<ToolTip DataContext="{Binding Path=Current}">
<MultiBinding Converter="{StaticResource OptConverter}">
<Binding Path="Opt" />
<Binding Path="Type" />
</MultiBinding>
</ToolTip>
</TextBlock.ToolTip>
</TextBlock>
</DockPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
The code not working is:
<TextBlock.ToolTip>
<ToolTip DataContext="{Binding Path=Current}">
<MultiBinding Converter="{StaticResource OptConverter}">
<Binding Path="Opt" />
<Binding Path="Type" />
</MultiBinding>
</ToolTip>
</TextBlock.ToolTip>
At present the Converter is returning an empty string as both 'values[0] == System.Windows.DependencyProperty.UnsetValue' and 'values[1] == System.Windows.DependencyProperty.UnsetValue' return true. These values are never set.
Because of the logical tree (I think) the TextBlock.ToolTip default binding is 'Current.Opt'. For the MultiBinding I also need to refer to 'Type' which is another property of 'Current'. So to get around this I have set 'ToolTip DataContext="{Binding Path=Current}"' - this isn't working as expected - what am I doing wrong?
I know I could do this easily in the Code behind, but we are employing MVVM, so would like to avoid it if possible.
Any help greatly appreciated!
Thank you
Try to do it in this way,
1.Does this give DependencyProperty.UnsetValue in the Converter? Otherwise, what is coming in to the converter?
<TextBlock.ToolTip>
<MultiBinding Converter="{StaticResource OptConverter}">
<Binding RelativeSource="{RelativeSource Self}" />
<Binding RelativeSource="{RelativeSource Self}" />
</MultiBinding>
</TextBlock.ToolTip>
2.Does this give DependencyProperty.UnsetValue in the Converter?
<TextBlock.ToolTip>
<MultiBinding Converter="{StaticResource OptConverter}">
<Binding RelativeSource="{RelativeSource Self}" Path="Current"/>
<Binding RelativeSource="{RelativeSource Self}" Path="Current"/>
</MultiBinding>
</TextBlock.ToolTip>
At several points in my current application, I have an ItemTemplate such as the following:
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<ToggleButton Margin="2,0" Content="{Binding}" Tag="{Binding}" Click="ToggleButton_Click">
<ToggleButton.IsChecked>
<MultiBinding Mode="OneWay" Converter="{StaticResource EqualityConverter}">
<Binding RelativeSource="{RelativeSource Self}" Path="Tag">
</Binding>
<Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type cc:ToggleButtonPanel}}" Path="SelectedItem">
</Binding>
</MultiBinding>
</ToggleButton.IsChecked>
</ToggleButton>
</DataTemplate>
</ItemsControl.ItemTemplate>
Now, I've stepped through the converter and it returns true and false as expected, but the controls do not change their ischecked state... There are no binding errors, and this only happens when using an ItemsTemplate/DataTemplate combo. Has anyone else seen this behaviour?