I'm trying to create a context menu for a list box which displays elements in the context menu from the list box. I am able to accomplish this by using the following XAML:
<Window.Resources>
<ContextMenu x:Key="contextMenu"
ItemsSource="{Binding Items,
RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListBox}}}" >
<ContextMenu.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Content}"/>
</DataTemplate>
</ContextMenu.ItemTemplate>
</ContextMenu>
<Style TargetType="{x:Type ListBox}">
<Setter Property="ContextMenu" Value="{StaticResource contextMenu}"/>
</Style>
</Window.Resources>
This works great for one list box. However, when I have a second list box, the context menu keeps showing the elements from the first list box. In other words, the ItemsSource of the context menu does not change. Only the first time that the context menu is opened is the ItemsSource property set. For example:
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<ListBox x:Name="first" >
<ListBoxItem>First 1</ListBoxItem>
<ListBoxItem>First 2</ListBoxItem>
<ListBoxItem>First 3</ListBoxItem>
<ListBoxItem>First 4</ListBoxItem>
<ListBoxItem>First 5</ListBoxItem>
</ListBox>
<ListBox x:Name="second" Grid.Column="2" >
<ListBoxItem>Second 1</ListBoxItem>
<ListBoxItem>Second 2</ListBoxItem>
<ListBoxItem>Second 3</ListBoxItem>
<ListBoxItem>Second 4</ListBoxItem>
<ListBoxItem>Second 5</ListBoxItem>
</ListBox>
</Grid>
I would like to set the context menu in a Style because I have many instances of a listbox and do not want to define a separate context menu for each listbox.
UPDATE:
I finally figured out how to fix it. I just need to bind to the PlacementTarget.Items and using a self relative source instead of using a find ancestor relative source.
<ContextMenu x:Key="contextMenu"
ItemsSource="{Binding PlacementTarget.Items,
RelativeSource={RelativeSource Self}}" >
Found the answer, I just need to bind to the PlacementTarget.Items and using a self relative source instead of using a find ancestor relative source.
<ContextMenu x:Key="contextMenu"
ItemsSource="{Binding PlacementTarget.Items,
RelativeSource={RelativeSource Self}}" >
I think the issue you're having here is due to the fact that the context menu is part of a different visual tree. That is, you cannot find the ListBox ancestor because it is not actually an ancestor of the context menu.
If you look at the debug panel of Visual Studio, you should see some warnings about the failing binding expression. Do you?
Related
ComboBox items were not displaying, if we try to keep that combobox in an ItemsCotrol. Please click here for understanding my requirement
My requirement is to keep a combobox in an ItemsControl, so that the ItemsControl qill be having 5 Comboboxes in it and each combox will be having a collection of items which we can select. So for that i tried with the below code and able to get the comboboxes in the ItemsControl, but the comboboxes collection is getting filled, any suggestions or workaround please..
<xamDataPresenter:Field Label="Reqs" BindingType="Unbound" Row="0" Column="4">
<xamDataPresenter:Field.CellValuePresenterStyle>
<Style TargetType="{x:Type xamDataPresenter:CellValuePresenter}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type xamDataPresenter:CellValuePresenter}">
<ItemsControl Name="I" ItemsSource="{Binding Path=DataItem.CollectionCount}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Path=DataItem.Collection}"/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</xamDataPresenter:Field.CellValuePresenterStyle>
</xamDataPresenter:Field>
Ok, I've written up the most basic of ItemsControl to try and explain how these things work, which you can hopefully adapt for whatever your using for your dataitems.
So in your window's resources i've created a datatemplate. This respresents a repeating step and will be based on a DataItem. In this case my DataItem has 2 properties: DataItemProperty(string) and SelectedItem. The SelectedItem will have the same DataType of whatever it is your planning on showing in the combobox.
<DataTemplate x:Key="StepTemplate">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<TextBlock Text="{Binding Path=DataItemProperty}" Grid.Column="0"/>
<ComboBox Grid.Column="1" ItemsSource="{Binding Path=DataContext.ItemsToSelectFrom, Mode=OneWay, RelativeSource={RelativeSource AncestorType=Window}}"
SelectedItem="{Binding Path=SelectedItem, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</Grid>
</DataTemplate>
The combobox in this example will be getting a list of available options from the code behind/viewmodel and not the DataItem, but when you select something it updates the SelectedItem property on the DataItem.
Then to show your items:
<ItemsControl
Focusable="False"
ItemTemplate="{StaticResource StepTemplate}"
ItemsSource="{Binding Path=Steps, Mode=OneWay}" />
So Steps is a property in my codebehind/viewmodel that will determine how many 'rows' get displayed.
The itemsControl allows you to add repeating sets of data easily, without having to write the same xaml multiple times.
Hope that helps?
I have a list view that displays a collection of items, each item has as its underlying data a view model (MVVM).
What I would like to do is display different menu items within the context menu when the user right clicks one of these list view items. The menu items displayed is dependent on the type of the item selected (i.e. the type of the underlying view model).
I would expect the below to work, but it does not (no items are displayed in the context menu).
<ListView.ContextMenu>
<ContextMenu DataContext="{Binding Path=PlacementTarget.SelectedItem, RelativeSource={RelativeSource Self}}">
<ContextMenu.Resources>
<DataTemplate DataType="{x:Type ViewModels:ViewModel1}">
<MenuItem Header="DoStuffForVM1" Command="{Binding DoStuffForVM1Command}"/>
</DataTemplate>
<DataTemplate DataType="{x:Type ViewModels:ViewModel2}">
<MenuItem Header="DoStuffForVM2" Command="{Binding DoStuffForVM2Command}"/>
</DataTemplate>
</ContextMenu.Resources>
<ContentPresenter ContentSource="{Binding}" />
</ContextMenu>
</ListView.ContextMenu>
Any ideas?
Thanks.
this works for me:
<ListView.ContextMenu>
<ContextMenu>
<ContentPresenter Content="{Binding Path=PlacementTarget.SelectedItem,
RelativeSource={RelativeSource AncestorType=ContextMenu}}" >
<ContentPresenter.Resources>
<DataTemplate DataType="{x:Type ViewModels:ViewModel1}">
<MenuItem Header="DoStuffForVM1" Command="{Binding DoStuffForVM1Command}"/>
</DataTemplate>
<DataTemplate DataType="{x:Type ViewModels:ViewModel2}">
<MenuItem Header="DoStuffForVM2" Command="{Binding DoStuffForVM2Command}"/>
</DataTemplate>
</ContentPresenter.Resources>
</ContentPresenter>
</ContextMenu>
</ListView.ContextMenu>
That is because you are setting the ContextMenu of the ListView, so your DataContext is the outer context of the ListView, rather than the ViewModel of an individual list item.
You need to set the ContextMenu of each item instead. For instance, using a style:
<ListView.Resources>
<ContextMenu x:Key="ItemContextMenu">
<MenuItem Header="DoStuffForVM1" Command="{Binding DataContext.DoStuffForVM1Command, RelativeSource={RelativeSource AncestorType={x:Type ListView}}"/>
</ContextMenu>
</ListView.Resources>
<ListView.ItemContainerStyle>
<Style TargetType="{x:Type ListViewItem}">
<Setter Property="ContextMenu" Value="{StaticResource ItemContextMenu}"/>
</Style>
</ListView.ItemContainerStyle>
However, the above does not account for the different types of menu.
If you are defining data templates for your listview for each type, the easiest way would be to define the ContextMenu explicitly in each DataTemplate.
If not, you'll have to do it with triggers in the style. You'll probably have to write a converter to be able to trigger on object type.
I created a WPF application and am following MVVM Pattern. I have a context menu in my xaml and I need to bind the command and Header text. Using the following code I can bind the Header of the context menu with the "MenuItemName" which is a property in BOList which is an observable collection. My issue is that command is not getting fired? I changes the Item source of the Context Menu to datacontext
(DataContext="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource Self}}")
Command is working fine but my header is getting blank. Is there a way to bind my header and command of a menu item? Here the command MenuClick is a Icommand property in the VM and MenuItemName is a property inside BOList which is an observable collection binded to my ListBox.
<Grid>
<StackPanel Orientation="Vertical">
<Button x:Name="btnClickMe" Command="{Binding ButtonCommand}" Content="Click Me" />
<ListBox ItemsSource="{Binding BOList}" x:Name="lstDemo" SelectedItem="{Binding BussinessObj,Mode=OneWayToSource}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel x:Name="stkStyleRender" Orientation="Horizontal" Background="Cyan" Width="525" Tag="{Binding DataContext, RelativeSource={RelativeSource AncestorType={x:Type ListBox}}}" >
<TextBlock x:Name="txtId" Text="{Binding FirstName}"></TextBlock>
<TextBlock x:Name="txtName" Text="{Binding LastName}"></TextBlock>
<StackPanel.ContextMenu>
<ContextMenu x:Name="cntMnuTest" ItemsSource ="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource Self}}" >
<MenuItem Header="{Binding MenuItemName}" Command="{Binding MenuClick}" CommandParameter="Icon"></MenuItem>
</ContextMenu>
</StackPanel.ContextMenu>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
Hi Identified the issue.
If we set Item Source of the context menu to BOList (observable collection ) command wont get fired because the ICommand definition is in Window data context (vm).
We need to handle the code like wise.
Since debugging is not possible for binding , I was beating around the bush :-)
This link helped me a lot WPF Tutorial - Debug Databinding Issues in WPF
In context menu use DataContext instead of using Items source
then bind your menu item
try this:
<MenuItem Header="{Binding Path=PlacementTarget.MenuItemName, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}" Command="{Binding Path=PlacementTarget.MenuClick, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}" />
<DataTemplate x:Key="_ItemTemplateA">
<Grid Tag="{Binding Path=DataContext.Command, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ContentControl Content="{Binding}" ContentTemplate="{StaticResource ContentTemplateB}" Grid.Row="0" />
<ContentControl Name="uiContentPresenter" Content="{Binding ContentView}" Grid.Row="1" Height="0" />
<ContentControl DataContext="{Binding IsContentDisplayed}" DataContextChanged="IsDisplayed_Changed" Visibility="Collapsed" />
<Grid.ContextMenu>
<ContextMenu>
<MenuItem Header="Text"
Command="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}"
CommandParameter="{Binding}" />
</ContextMenu>
</Grid.ContextMenu>
</Grid>
</DataTemplate>
The above data template is applied to an ItemsControl. The issue is that for the ContextMenu that is specified for the Grid, the PlacementTarget property is never actually getting set to anything so I cannot get to the Tag property of the Grid which is necessary for passing the Command that should execute on the parent UserControl down to the context menu. I've based this approach off of similar examples such as this: http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/0244fbb0-fd5f-4a03-bd7b-978d7cbe1be3/
I've not been able to identify any other good way to pass this command down. This is setup this way because we are using an MVVM approach so the command we have to execute lives in the View Model of the user control this template is applied in. I've tried explicitly setting the PlacementTarget in a few different ways but it still always shows up as not set.
I realise that this is old and answered, but it doesn't seem properly answered. I came across a similar post and left a full answer. You might like to take a look as you can get it working with just a few adjustments to your code.
First, name your view UserControl... I generally name all of mine This for simplicity. Then remembering that our view model is bound to the DataContext of the UserControl, we can bind to the view model using {Binding DataContext, ElementName=This}.
So now we can bind to the view model, we have to connect that with the ContextMenu.DataContext. I use the Tag property of the object with the ContextMenu (the PlacementTarget) as that connection, in this example, a Grid:
<DataTemplate x:Key="YourTemplate" DataType="{x:Type DataTypes:YourDataType}">
<Grid ContextMenu="{StaticResource Menu}" Tag="{Binding DataContext,
ElementName=This}">
...
</Grid>
</DataTemplate>
We can then access the view model properties and commands in the ContextMenu by binding the ContextMenu.DataContext property to the PlacementTarget.Tag property (of the Grid in our example):
<ContextMenu x:Key="Menu" DataContext="{Binding PlacementTarget.Tag, RelativeSource=
{RelativeSource Self}}">
<MenuItem Header="Delete" Command="{Binding DeleteFile}" CommandParameter=
"{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource
AncestorType=ContextMenu}}" CommandTarget="{Binding PlacementTarget,
RelativeSource={RelativeSource Self}}" />
</ContextMenu>
Note the binding on the MenuItem.CommandTarget property. Setting this ensures that the target element on which the specified command is raised is the PlacementTarget, or the Grid in this case.
Also note the CommandParameter binding. This binds to the DataContext of the PlacementTarget, or the Grid in this case. The DataContext of the Grid will be inherited from the DataTemplate and so your data item is now bound to the object parameter in your Command if you're using some implementation of the ICommand interface:
public bool CanExecuteDeleteFileCommand(object parameter)
{
return ((YourDataType)parameter).IsInvalid;
}
public void ExecuteDeleteFileCommand(object parameter)
{
Delete((YourDataType)parameter);
}
Or if you are using some kind of RelayCommand delegates directly in your view model:
public ICommand Remove
{
get
{
return new ActionCommand(execute => Delete((YourDataType)execute),
canExecute => return ((YourDataType)canExecute).IsInvalid);
}
}
We have the same problem, but it works randomly. A contextmenu inside the controltemplate in a style for a listbox. We have tried to move the contextmenu to different levels inside the template but the same error occurs.
We think it might be connected to the refreshing of our ICollectionView that is the itemssource of the ListBox.
It seems that when the view refreshes the relative source binding inside the contextmenu is being evaluated before the PlacementTarget is being set.
It feels like a bug in either collectionviewsource or the ContextMenu of WPF...
Here is a working standalone XAML-only example based on your test case: a ContextMenu that retrieves a Command from the DataContext of its PlacementTarget using a Tag. You can reintroduce portions of your code until it stops working to try to find where the problem is:
<Grid>
<Grid.Resources>
<PointCollection x:Key="sampleData">
<Point X="10" Y="20"/>
<Point X="30" Y="40"/>
</PointCollection>
<DataTemplate x:Key="_ItemTemplateA">
<Grid Tag="{Binding Path=DataContext, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DockPanel}}}">
<TextBlock Text="{Binding X}"/>
<Grid.ContextMenu>
<ContextMenu>
<MenuItem Header="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" CommandParameter="{Binding}"/>
</ContextMenu>
</Grid.ContextMenu>
</Grid>
</DataTemplate>
</Grid.Resources>
<DockPanel DataContext="{x:Static ApplicationCommands.Open}">
<ListBox ItemTemplate="{StaticResource _ItemTemplateA}" ItemsSource="{StaticResource sampleData}"/>
</DockPanel>
</Grid>
In this post,
ContextMenu.PlacementTarget is filled up from ContextMenuService.PlacementTarget when you do right click with mouse on button.
It means ContextMenu.PlacementTarget is filled up when the menu is shown up. You can check that by snoop.
EDIT 1
This code works fine.
<DataGrid.RowStyle>
<Style TargetType="DataGridRow" BasedOn="{StaticResource DataGridRowBaseStyle}">
<Setter Property="Tag" Value="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=DataGrid}, Path=DataContext}"/>
<Setter Property="ContextMenu">
<Setter.Value>
<ContextMenu Style="{StaticResource ContextMenuStyle}"
ItemContainerStyle="{StaticResource MenuItemStyle}">
<MenuItem Header="Enable" Command="{Binding Path=PlacementTarget.Tag.(viewModels:PrinterListPageViewModel.EnableCommand), RelativeSource={RelativeSource AncestorType=ContextMenu}}"/>
</ContextMenu>
</Setter.Value>
</Setter>
</Style>
</DataGrid.RowStyle>
Ok, this is an embarassingly simple-looking problem, but is driving me crazy. I'm learning about DataTemplating and am trying to apply a very VERY simple ItemTemplate to a ListBox.
However, when I run my app, the template is completely ignored and I just get the standard-looking listbox, whereas in fact I'd expect to see a list of checkboxes with 'Test' along side.
I've tried this several times and always the same result. I've checked several resource on Google and all have the same kind of syntax for defining and ItemTemplate on a ListBox, so I really cannot see where I'm going wrong.
Code...
<Grid x:Name="LayoutRoot">
<ListBox x:Name="TestList"
SelectionMode="Multiple">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<CheckBox Content="Check this checkbox!"/>
<TextBlock>Test</TextBlock>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
<ListBox.Items>
<ListBoxItem>Bob</ListBoxItem>
<ListBoxItem>Jim</ListBoxItem>
<ListBoxItem>Dave</ListBoxItem>
<ListBoxItem>Larry</ListBoxItem>
<ListBoxItem>Tom</ListBoxItem>
</ListBox.Items>
</ListBox>
</Grid>
Any help greatly appreciated. Sorry for such a dumb-seeming question, but I've really fallen at the first hurdle here :(
AT
ItemTemplate wont work when you put ListBoxItem directly as items. General concept is you databind a CRL collection to the ListBox.ItemsSource and then specify the ItemTemplate. Check the below code.
<Grid x:Name="LayoutRoot">
<ListBox x:Name="TestList" SelectionMode="Multiple">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<CheckBox Content="Check this checkbox!"/>
<TextBlock Text="{Binding}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
<ListBox.Items>
<sys:String>Bob</sys:String>
<sys:String>Jim</sys:String>
<sys:String>Dave</sys:String>
<sys:String>Larry</sys:String>
<sys:String>Tom</sys:String>
</ListBox.Items>
</ListBox>
</Grid>
where sys is xmlns:sys="clr-namespace:System;assembly=mscorlib"
In this way, there are 5 ListBoxItems getting generated in the background and added to the ListBox.
You can use ItemContainerStyle instead of ItemTemplate if you want to add ListBoxItems directly to the ListBox.
Doing so, however, is only recommended when you need unique characteristics on a per item level.
If you are planning on all the items looking the same or making a dynamic list using ItemsSource, I would recommend you add strings (or another custom object) to your list and use ItemTemplate to display your items. (see Jobi Joy's answer)
Here's an example using ItemContainerStyle:
<ListBox
x:Name="TestList"
SelectionMode="Multiple">
<ListBox.ItemContainerStyle>
<Style
TargetType="ListBoxItem">
<Setter
Property="Template">
<Setter.Value>
<ControlTemplate
TargetType="ListBoxItem">
<StackPanel>
<CheckBox
Content="Check this checkbox!" />
<TextBlock
Text="{TemplateBinding Content}" />
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListBox.ItemContainerStyle>
<ListBox.Items>
<ListBoxItem>Bob</ListBoxItem>
<ListBoxItem>Jim</ListBoxItem>
<ListBoxItem>Dave</ListBoxItem>
<ListBoxItem>Larry</ListBoxItem>
<ListBoxItem>Tom</ListBoxItem>
</ListBox.Items>
</ListBox>
For some reason DataTemplate can still be ignored if the ListBox is populated using ItemsSource e.g:
<ListBox Name="Test" x:FieldModifier="public" ItemsSource="{Binding UpdateSourceTrigger=PropertyChanged}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBox Text="{Binding Text, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Note that this is bound to an ObservableCollection containing objects (TextAdapter : INotifyPropertyChanged) with one property: string Text {...}