How can I use a converter without a binding path? I've got some radio buttons and would like to have a converter that is passed a string and that then returns whether or not a checkbox is checked:
<RadioButton IsChecked="{Binding Converter={StaticResource LanguageToBoolConverter}, ConverterParameter='de_DE'}" Command="{Binding ChangeLanguageCommand, ElementName=LangSelector}" CommandParameter="de-DE">
However, I get the error message Two-way binding requires Path or XPath.
In such case you need to specify path to current DataContext
IsChecked="{Binding Path=., Converter={StaticResource LanguageToBoolConverter}, ..."
From MSDN:
Optionally, a period (.) path can be used to bind to the current source. For example, Text="{Binding}" is equivalent to Text="{Binding Path=.}".
Related
I have a User control and I bind the tooltip of that control into some object's property
<usercontrols:ucButton x:Name="xSaveCurrentBtn" ButtonType="ImageButton" ButtonFontImageSize="16" ButtonImageWidth="18" ButtonImageHeight="18" ButtonImageType="Save" Click="xSaveSelectedButton_Click" ButtonStyle="{StaticResource $ImageButtonStyle_Menu}" DockPanel.Dock="Right" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="0,0,0,0">
<usercontrols:ucButton.ToolTip>
<ToolTip Content="{Binding ItemName, Mode=OneWay}" ContentStringFormat="Save {0}"/>
</usercontrols:ucButton.ToolTip>
</usercontrols:ucButton>
from the code I set the data context of the ucButton to be my object:
xSaveCurrentBtn.DataContext = WorkSpace.Instance.CurrentSelectedItem;
sometimes the CurrentSelectedItem is null, and if this is the case I want the tooltip to display "No Item Selected"
I tried doing this:
xSaveCurrentBtn.Tooltip = "No Item Selected";
but when the CurrentSelectedItem isn't null and I reset the xSaveBtn.DataContext to that object, I am still seeing the No Item Selected tooltip as if my WPF tooltip section was overriden and its no longer binding into the datacontext ItemName Property
You are trying to set a property to two values at the same time. It's impossible.
What you are doing in XAML is equivalent to:
xSaveCurrentBtn.Tooltip = new ToolTip() {.....};
When you setting a string value to the same property, the previous value is lost. And it is not possible to restore it if you do not save it first.
You might want to assign a value in case of a binding error:
<ToolTip Content="{Binding ItemName,
Mode=OneWay,
FallbackValue='No Item Selected'}"
ContentStringFormat="Save {0}"/>
how can I bind the data context to update to be the new CurrentSelectedItem without explicitly setting it?
Assuming that «WorkSpace.Instance» is an immutable property that returns an instance of «WorkSpace» and «CurrentSelectedItem» is a property with an «INotifyPropertyChanged.PropertyChanged» notification, then you can do this:
<usercontrols:ucButton DataContext="{Binding CurrentSelectedItem, Source={x:Static viewmodels:WorkSpace.Instance}}" ...>
The «viewmodels» prefix depends on the assembly and namespace in which the «WorkSpace» class is declared.
you can use ContentTemplate with TextBlock, which will either use StringFormat, or TargetNullValue depending on ItemName being null:
<usercontrols:ucButton.ToolTip>
<ToolTip Content="{Binding ItemName}">
<ToolTip.ContentTemplate>
<DataTemplate>
<TextBlock Text="{Binding StringFormat='Save {0}',
TargetNullValue='No Item Selected'}"/>
</DataTemplate>
</ToolTip.ContentTemplate>
</ToolTip>
</usercontrols:ucButton.ToolTip>
or if you bind Tooltip.Content differently:
<usercontrols:ucButton.ToolTip>
<ToolTip Content="{Binding}">
<ToolTip.ContentTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=ItemName,
StringFormat='Save {0}',
FallbackValue='No Item Selected'}"/>
</DataTemplate>
</ToolTip.ContentTemplate>
</ToolTip>
</usercontrols:ucButton.ToolTip>
I'm having trouble getting my binding to work correctly. Basically I have this, call this Control1.xaml. The commented out portion of the code binds correctly and updates as expected.
<progControls:CalibrationSummary
</progControls:CalibrationSummary>
<!--<TextBlock Text="{Binding Path=NumberOfCalibrations, Mode=OneWay}"/>-->
However, if I put that commented code in a custom control called CalibrationsSummary.xaml, I cannot bind this to NumberOfCalibrations.
Here's what CalibrationsSummary looks like
<Grid>
<TextBlock Text="{Binding Path=NumberOfCalibrations, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}"/>
</Grid>
Note that I do use RelativeSource to try to get the property associated with Control1.xaml, tried TemplateBinding also. What am I doing wrong?
CalibrationSummary has no TemplatedParent unless you have put it in a ControlTemplate.
If you don't explicitly set the DataContext of the property of CalibrationSummary somewhere, it will inherit the DataContext from its parent control (which I assume is Control1) and then you can bind any property of this control's DataContext as usual without specifying any source:
<Grid>
<TextBlock Text="{Binding Path=NumberOfCalibrations}"/>
</Grid>
I have a template that receives a string as its data type:
<DataTemplate x:DataType="System:String">
<TextBlock Text="{x:Bind}" />
</DataTemplate>
But this binding technique gives me a build error. How can I use {x:Bind} without a path value? I want to bind the string, not a property in the string.
You actually can do Text="{x:Bind}" without specifying a path. The Designer will complain but it's safe to ignore it.
I think the problem is the way you define the string type. Note in WinRT XAML it now writes as x:String.
So this should work -
<DataTemplate x:Key="GroupTemplate" x:DataType="x:String">
<TextBlock Text="{x:Bind}" />
</DataTemplate>
I have created a dependency property in one of the usercontrols but need some way to bind it into another XAML(another usercontrol).Here is the C# code
DateRangeSelectorControl.cs
public static readonly DependencyProperty TodayDateProperty =
DependencyProperty.Register("TodayDate",
typeof(DateTime),
typeof(DateRangeSelectorControl),
new PropertyMetadata(null, TodayDateChanged));
I have another XAML(ActivityListMenuControlView.xaml) where i need to bind this property(TodayDateProperty) so that it can be exposed and it's callback called.
Here is the XAML code:
<DateRangeSelector:DateRangeSelectorControl x:Name="DateRangeSelector"
Grid.Column="1"
Margin="10 0 0 0"
HorizontalAlignment="Left"
VerticalAlignment="Center"
AutomationProperties.AutomationId="AID_TaskListDateRangeSelector"
DateRangeUpdatedCmd="{Binding Path=DateRangeSelectionUpdatedCommand}"
FontSize="{StaticResource TaskListMenuFontSize}"
RangeOptions="{Binding Path=DateRangeSelectionOptions,
Mode=OneTime}"
SelectedDateRange="{Binding Path=SelectedRange,
Mode=TwoWay}"
Visibility="{Binding Path=ShowFilterOptions,
Converter={StaticResource boolToVisibility}}" />
Is there any way?
UPDATE:
As per the suggestion from O.R Mapper, i have made the following change into this XAML(ActivityListMenuControlView.xaml):
<DateRangeSelector:DateRangeSelectorControl x:Name="DateRangeSelector"
Grid.Column="1"
Margin="10 0 0 0"
HorizontalAlignment="Left"
VerticalAlignment="Center"
AutomationProperties.AutomationId="AID_TaskListDateRangeSelector"
DateRangeUpdatedCmd="{Binding Path=DateRangeSelectionUpdatedCommand}"
FontSize="{StaticResource TaskListMenuFontSize}"
RangeOptions="{Binding Path=DateRangeSelectionOptions,
Mode=OneTime}"
SelectedDateRange="{Binding Path=SelectedRange,
Mode=TwoWay}"
Visibility="{Binding Path=ShowFilterOptions,
Converter={StaticResource boolToVisibility}}"
TodayDateProperty="{Binding TodayDate, ElementName=DateRangeSelector}"
Still i get an error : Property or event expected. Upon compilation i get the following errors:
Error 2 The property 'TodayDateProperty' was not found in type 'DateRangeSelectorControl'.
Error 4 Default value type does not match type of property 'TodayDate'.
Any idea?
UPDATE:
As suggested by Sheridan, i changed the XAML to something like:
<DateRangeSelector:DateRangeSelectorControl x:Name="DateRangeSelector"
Grid.Column="1"
Margin="10 0 0 0"
HorizontalAlignment="Left"
VerticalAlignment="Center"
AutomationProperties.AutomationId="AID_TaskListDateRangeSelector"
DateRangeUpdatedCmd="{Binding Path=DateRangeSelectionUpdatedCommand}"
FontSize="{StaticResource TaskListMenuFontSize}"
RangeOptions="{Binding Path=DateRangeSelectionOptions,
Mode=OneTime}"
SelectedDateRange="{Binding Path=SelectedRange,
Mode=TwoWay}"
Visibility="{Binding Path=ShowFilterOptions,
Converter={StaticResource boolToVisibility}}"
TodayDate="{Binding TodayDate, ElementName=DateRangeSelector}"/>
Wrapper property "TodayDate" is defined in DateRangeSelector as below:
DateRangeSelector.cs
public DateTime TodayDate
{
get { return (DateTime)GetValue(TodayDateProperty); }
set { SetValue(TodayDateProperty, value); }
}
And in the viewmodel(ActivityListMenuControlViewModel.cs) i created another "TodayDate"(as specified in the binding) as belowL
public DateTime TodayDate
{
get;
set;
}
On compilation i get the below errors:
Error 2 The property 'TodayDate' was not found in type 'DateRangeSelectorControl'.
Error 12 Default value type does not match type of property 'TodayDate'.
Any help?
Assuming that the property belongs to a class named SomeClass, of which an instance is declared in ActivityListMenuControlView.xaml, and is called SomeProperty, and assuming the Xaml snippet you are showing is a part of ActivityListMenuControlView.xaml, you can simply bind it like this:
<SomeClass SomeProperty="{Binding TodayDate, ElementName=DateRangeSelector}"/>
It seems to me as though your error is telling you what the problem is:
The property 'TodayDateProperty' was not found in type 'DateRangeSelectorControl'. Error 4 Default value type does not match type of property 'TodayDate'.
This is because you did not register a DependencyProperty named TodayDateProperty in your control. So instead, try using the name of the DependencyProperty that you did register - TodayDate:
<DateRangeSelector:DateRangeSelectorControl x:Name="DateRangeSelector"
Grid.Column="1"
Margin="10 0 0 0"
HorizontalAlignment="Left"
VerticalAlignment="Center"
AutomationProperties.AutomationId="AID_TaskListDateRangeSelector"
DateRangeUpdatedCmd="{Binding Path=DateRangeSelectionUpdatedCommand}"
FontSize="{StaticResource TaskListMenuFontSize}"
RangeOptions="{Binding Path=DateRangeSelectionOptions, Mode=OneTime}"
SelectedDateRange="{Binding Path=SelectedRange, Mode=TwoWay}"
Visibility="{Binding Path=ShowFilterOptions,
Converter={StaticResource boolToVisibility}}"
TodayDate="{Binding TodayDate, ElementName=DateRangeSelector}" />
UPDATE >>>
Ok, I think that I see what your problem is now. You are trying to data bind from your control to a view model property. What your Binding.Path will look like will depend on how your view model is 'connected' to your view. Assuming that an instance of your view model is set as the DataContext for your view, you would then be able to access the view model property like this:
TodayDate="{Binding DataContext.TodayDate, RelativeSource={RelativeSource
AncestorType={x:Type UserControl}}}"
Of course, if your control is declared in MainWindow instead, then you would need to use the following syntax:
TodayDate="{Binding DataContext.TodayDate, RelativeSource={RelativeSource
AncestorType={x:Type MainWindow}}}"
When I add
<TextBlock Text="{Binding SettingName}" TextWrapping="Wrap" Margin="10,-2,10,0" Style="{StaticResource PhoneTextSubtleStyle}" />
Everuthing is ok. But when
<TextBlock x:Name="{Binding SettingTextBlockName}" Text="{Binding SettingName}" TextWrapping="Wrap" Margin="10,-2,10,0" Style="{StaticResource PhoneTextSubtleStyle}" />
constructor are breaking.
But I need different names in all elements.
x:Name is a special property. As a matter of fact it's not a property at all, it's an attribute that maps the name or id property of the element to x:Name. Binding only works when applied to a DependencyProperty, so it cannot work on x:Name. It must be set manually.
If you want to distinguish between objects in runtime, you can set the Tag attribute, which tolerates everything.
more on x:Name: http://msdn.microsoft.com/en-us/library/ms752290.aspx
You should use FrameworkElement.Tag property, according to MSDN
FrameworkElement.Tag gets or sets an arbitrary object value that can
be used to store custom information about this element.
What use is the Tag property in .net