As the title says, I'm trying to bind a function to the RecordContextMenu of a Syncfusion SfTreeGrid, the problem is that it's not working on this particular element, every time I tried binding the function the "No target found for method" exception is thrown.
I´ve tried the Tag and TargetWithoutContext method on a "regular" SfTreeGrid ContextMenu and it works without problems
<syncfusion:SfTreeGrid Tag="{Binding DataContext, ElementName=Container}">
...
...
<syncfusion:SfTreeGrid.ContextMenu>
<ContextMenu Name="cm" cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
<MenuItem Header="Test Action"
cal:Message.Attach="Test"/>
</ContextMenu>
</syncfusion:SfTreeGrid.ContextMenu>
The Container is a Grid
Now when using the same method on the RecordContextMenu the exception is thrown
<syncfusion:SfTreeGrid.RecordContextMenu>
<ContextMenu Name="cm" cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
<MenuItem Header="Test Action"
cal:Message.Attach="Test"/>
</ContextMenu>
</syncfusion:SfTreeGrid.RecordContextMenu>
Maybe I'm using the wrong RelativeSource here but I don't know how can I solve it.
PS: Already read the documentation for the SfTreeGrid and I know that you can bind the commands using the VM as a StaticResource but that gives me a new instance of the VM making my properties inaccessible.
Related
I have a static resource defined as follows:
<ContextMenu x:Key="TestContextMenu" DataContext="{Binding Path=PlacementTarget, RelativeSource={x:Static RelativeSource.Self}}">
<MenuItem Command="ApplicationCommands.Cut"/>
<!--<ContextMenu.ItemsSource>
<CompositeCollection>
<MenuItem Command="ApplicationCommands.Cut"/>
</CompositeCollection>
</ContextMenu.ItemsSource>-->
</ContextMenu>
My application works fine like this. However, I want to be able to add extra items to the context menu. So instead of adding menu items I want to use a CompositeCollection and then I run into binding issues. I minimized the problem and ended up with this. When I comment the MenuItem and uncomment the ContextMenu.ItemSource I get this error:
System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.ItemsControl', AncestorLevel='1''. BindingExpression:Path=HorizontalContentAlignment; DataItem=null; target element is 'MenuItem' (Name=''); target property is 'HorizontalContentAlignment' (type 'HorizontalAlignment')
If the datacontext is correct in the first situation why is it not correct anymore in the second situation?
Edit: I don't want to add items to the contextmenu dynamically. I want to use this contextmenu as kind of a 'base context menu' providing cut/copy and paste from a composite collection resource. In some places I want more than just these three and there I could use a custom context menu that use that same collection combined with those extra items. Just to clarify this is the xaml I have in mind, but I cut the problem down to the simpler piece above.
<CompositeCollection x:Key="TreeViewItemContextMenuItems">
<MenuItem Command="ApplicationCommands.Cut" CommandTarget="{Binding}"/>
<MenuItem Command="ApplicationCommands.Copy" CommandParameter="{Binding}"/>
<MenuItem Command="ApplicationCommands.Paste" CommandParameter="{Binding}"/>
<Separator/>
<MenuItem Command="ApplicationCommands.Delete" CommandParameter="{Binding}"/>
</CompositeCollection>
<ContextMenu x:Key="TreeViewItemContextMenu" DataContext="{Binding Path=PlacementTarget, RelativeSource={x:Static RelativeSource.Self}}">
<ContextMenu.ItemsSource>
<CompositeCollection>
<CollectionContainer Collection="{StaticResource TreeViewItemContextMenuItems}" />
</CompositeCollection>
</ContextMenu.ItemsSource>
</ContextMenu>
If you want to dynamically populate ContextMenu the better solution is do to as follows:
<ContextMenu
x:Key="TestContextMenu"
ItemsSource="{Binding MenuItems}">
</ContextMenu>
I removed DataContext="{Binding Path=PlacementTarget...}}" and added this ItemsSource="{Binding MenuItems}". MenuItems is a property of an object used as a data context. Here is an example of usage:
<Window>
...
<ItemsControl ContextMenu="{StaticResource ResourceKey=TestContextMenu}">
...
</ItemsControl>
</Window
In this case the context menu will inherit a data context from ItemsControl which in turn will inherit a data context from Window.
If you don't want to remove DataContext="{Binding Path=PlacementTarget...}}" then use the following code:
<ContextMenu
x:Key="TestContextMenu"
DataContext="{Binding Path=PlacementTarget, RelativeSource={x:Static RelativeSource.Self}}"
ItemsSource="{Binding DataContext.MenuItems}">
</ContextMenu>
EDIT:
You receive these errors because MenuItem controls by default try to bind some of their properties (HorizontalContentAlignment and VerticalContentAlignment) to ItemsControl using RelativeSource. The problem is that their are embeded inside CompositeCollection which doesn't support this kind of binding - see this article.
The problem will occure even if you override this binding in your XAML in this way:
<MenuItem Command="ApplicationCommands.Cut" CommandTarget="{Binding}"
HorizontalContentAlignment="Center" VerticalContentAlignment="Center"/>
Probably there is some workaround of this problem but personally I'll ignore these errors. They don't spoil anything in your application, don't they?
I have TreeView with HierarchicalDataTemplate. On TreeView I have ContextMenu
<TreeView Name="_packageTreeView" ItemsSource="{Binding PackageExtendedList}" Behaviors:TreeViewInPlaceEditBehavior.IsEditable="True">
<TreeView.ContextMenu>
<ContextMenu StaysOpen="true">
<MenuItem Header="Добавить пакет" Height="20" Command="{Binding AddPackageCommand}"
CommandParameter="{Binding ElementName=_packageTreeView, Path=SelectedItem}">
<MenuItem.Icon>
<Image Source="/Resources/ManualAdd.png" Width="15" Height="15"></Image>
</MenuItem.Icon>
</MenuItem>
</ContextMenu>
</TreeView.ContextMenu>
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Childs}">bla bla bla</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
As you can see, I bind Command to menu item. AddPackageCommand defined in ViewModell class as usually. Invoke command works fine, but I always have null in CommandParameter. I found some questions similar to my, but I don't understand solutions. For example:
CommandParameters in ContextMenu in WPF
Anyway it doesn't work for me :( What am I doing wrong?
Updated
That seems to be working, but it's all the same, I don't understand why CommandParameter doesn't work with TreeView.Name.
CommandParameter="{Binding PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}"
for examplle, such a sample works fine
<i:EventTrigger EventName="SelectedItemChanged">
<i:InvokeCommandAction Command="{Binding PackageTreeItemChangeCommand}" CommandParameter="{Binding ElementName=_packageTreeView, Path=SelectedItem}"/>
</i:EventTrigger>
What's the hell...
And anyway, I have TreeView object in CommandParameter, not TreeViewItem. I can get SelectedItem from TreeView, but how can I send exactly TreeViewItem as CommandParameter?
to Sheridan
Question was WHY this doesn't work.
CommandParameter="{Binding ElementName=_packageTreeView, Path=SelectedItem}"
And this works
CommandParameter="{Binding PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}"
WHY sometimes I can use direct TreeView control name and sometimes I cannot.
As I understand, matter is different DataContext of TreeView control and ContextMenu because ContextMenu has its own VisualTree and it is not the part of TreeView ViaualTree.
Unfortunately, that approach doesn't work too, I have null again. I set TreeView.Tag, sure.
<ContextMenu DataContext="{Binding PlacementTarget.Tag, RelativeSource={
RelativeSource Self}}" StaysOpen="true">
<MenuItem Header="Добавить пакет" Height="20" Command="{Binding AddPackageCommand}"
CommandParameter="{Binding ElementName=_packageTreeView, Path=SelectedItem}">
<MenuItem.Icon>
<Image Source="/Resources/ManualAdd.png" Width="15" Height="15"></Image>
</MenuItem.Icon>
</MenuItem>
</ContextMenu>
This is the easiest way, but if I have SelectedItem property in ViewModel it has no sense bind it to CommandParameter, because I already have it in ViewModel.
<MenuItem Header="Добавить пакет" Height="20" Command="{Binding AddPackageCommand}"
CommandParameter="{Binding SelectedItem}">
<MenuItem.Icon>
<Image Source="/Resources/ManualAdd.png" Width="15" Height="15"></Image>
</MenuItem.Icon>
</MenuItem>
You showed us that you already have an answer... why on earth did you post yet another question on this same subject instead of simply following the example in the answer? It doesn't work for you, because you didn't copy the answer properly.
In your example post answer, the Tag property is set to the TreeView control that the menu is applied on, but you haven't done this.
Your next problem is that you have ignored this Tag property again in the CommandParameter... somehow, you have changed this from the correct answer:
CommandParameter="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource
FindAncestor, AncestorType={x:Type ContextMenu}}}
to this in your question:
CommandParameter="{Binding PlacementTarget, RelativeSource={RelativeSource
FindAncestor, AncestorType={x:Type ContextMenu}}}"
All you needed to do was copy and paste it. All the same, you might have even more luck doing this:
<TreeView Tag="{Binding DataContext, RelativeSource={RelativeSource Self}}"
Name="_packageTreeView" ItemsSource="{Binding PackageExtendedList}"
Behaviors:TreeViewInPlaceEditBehavior.IsEditable="True">
<TreeView.ContextMenu>
<ContextMenu DataContext="{Binding PlacementTarget.Tag, RelativeSource={
RelativeSource Self}}" StaysOpen="true">
<MenuItem Header="Добавить пакет" Height="20" Command="{Binding AddPackageCommand}"
CommandParameter="{Binding ElementName=_packageTreeView, Path=SelectedItem}">
<MenuItem.Icon>
<Image Source="/Resources/ManualAdd.png" Width="15" Height="15"></Image>
</MenuItem.Icon>
</MenuItem>
</ContextMenu>
</TreeView.ContextMenu>
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Childs}">bla bla bla</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
Look at the TreeView.Tag property... this is set to its own DataContext, which means that whatever is set as the DataContext of the TreeView is now available in the Tag property object.
Next, look at the ContextMenu.DataContext property... this is set to the Tag property of the PlacementTarget, which is the control that the ContextMenu is applied to, or in this case, the Treeview.
If you haven't worked it out yet, this means that the DataContext of the ContextMenu is now set to the same object as the DataContext of the TreeView. If this is not what you want because your Command is on a different object, then just change the Binding path in the Tag property to point to wherever the object that had the Command is.
The last thing that you can do to make this simpler is to add a property to your view model/code behind that binds to the TreeView.SelectedItem property:
<TreeView SelectedItem="{Binding SelectedItem}"... />
Then you can simply refer to this property for your CommandParameter:
<MenuItem Header="Добавить пакет" Height="20" Command="{Binding AddPackageCommand}"
CommandParameter="{Binding SelectedItem}">
<MenuItem.Icon>
<Image Source="/Resources/ManualAdd.png" Width="15" Height="15"></Image>
</MenuItem.Icon>
</MenuItem>
This last part of course assumes that you have set your view model/code behind as the Tag property of the TreeView. If you still don't understand this, take a look at the Context Menus in WPF page on WPF Tutorial.NET.
UPDATE >>>
I simply don't understand why you posted this question. First you said you couldn't do something, but then provided us with a link to a valid solution in another post. After trying to help you, you then say that it did work, but you don't know why... but then you correctly answered your own question again:
As I understand, matter is different DataContext of TreeView control and ContextMenu because ContextMenu has its own VisualTree and it is not the part of TreeView ViaualTree.
As you said, the ContextMenu has its own visual tree. This means that it is not aware of controls, named or otherwise, in another visual tree. However, if the ContextMenu.DataContext is provided with an object such as the containing view, then it can be aware of controls in another visual tree (more specifically, the visual tree of the controls in the view).
This whole issue seems to be down to a lack of knowledge on your part about Binding in general and Binding.Path syntax more specifically. Please take a look at the following articles on MSDN for more help on this topic:
Binding.Path Property
Property Path Syntax
RelativeSource MarkupExtension
So many people try to run with WPF before they can walk.
I have my hierarchical treeview binding wonderfully to my ViewModel using Caliburn Micro. (The ViewModel has an Items property that returns an ObservableCollection - the treeview is named to this Items property - nothing wrong with the binding).
However the issue comes up with the context menu. The menu fires a method on an instance of the object that the treenode represents. What I rather want to achieve, is to have the menu fire a method on my root ViewModel, passing to it as a parameter the instance of the object represented by the clicked treenode.
Here is my XAML:
<HierarchicalDataTemplate DataType="{x:Type m:TaskGrouping}"
ItemsSource="{Binding Children}">
<Label Content="{Binding Name}"
FontWeight="Bold">
<Label.ContextMenu>
<ContextMenu>
<MenuItem Header="Add New SubFolder"
cal:Message.Attach="AddNewSubfolder" />
<MenuItem Header="Remove this folder"
cal:Message.Attach="RemoveFolder" />
</ContextMenu>
</Label.ContextMenu>
</Label>
</HierarchicalDataTemplate>
What changes do I need to make to my XAML in order to achieve what I want?
ContextMenus are located in a separate visual tree from everything else - it can be a pain to get the bindings right (I often have 10-15 minutes of fighting the bindings on them to get them right!)
You've got your Message.Attach attached property set, all you need to do is ensure that the action target is pointing to the VM rather than the data item. You can use Action.TargetWithoutContext to specify the target for actions (CM will otherwise use DataContext)
You will also need to get a binding path which points to the other visual tree - try using RelativeSource bindings - the ContextMenu also has a property called PlacementTarget which should point to the element that the ContextMenu is attached to
So possibly:
cal:Action.TargetWithoutContext="{Binding DataContext, RelativeSource={RelativeSource AncestorType=Label}}"
or
cal:Action.TargetWithoutContext="{Binding PlacementTarget.DataContext}"
You might have to experiment as I often get this almost right first time!
EDIT by OP(Shawn):
This is what worked for me eventually:
<Label Content="{Binding Name}"
Tag="{Binding DataContext, ElementName=LayoutRoot}">
<Label.ContextMenu>
<ContextMenu
cal:Action.TargetWithoutContext="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
<MenuItem Header="Run Task Now" cal:Message.Attach="SomeRootViewModelMethod($dataContext)" />
I'm working on a WPF application and I'm using the MVVM pattern. I use MVVMLight to help me handle some Events. I need to forward the "Click" event so that I can pass the arguments as well so that I can know for sure which item that sent the event. If I use the "Command" I cant know for sure that it was the selected item that sent the event - as the item doesnt need to be selected to right click on it.
This is my code for displaying a list of "order lines". There are two types of order lines, and for one of the data types; "AccessoryOrderLine" - I want to add a context menu.
My problem is that I cannot access my Window's DataContext. I've named the root node in the Window "root", and I'm trying to access the root's DataContext, but this failes with the following error:
System.Windows.Data Error: 4 : Cannot find source for binding with
reference 'ElementName=root'.
BindingExpression:Path=DataContext.PackAccessory; DataItem=null;
target element is 'EventToCommand' (HashCode=5903270); target property
is 'Command' (type 'ICommand')
<ListBox HorizontalContentAlignment="Stretch" Margin="10,0,10,10" DockPanel.Dock="Bottom" Grid.Row="1" ItemsSource="{Binding OrderLines, NotifyOnSourceUpdated=True, NotifyOnTargetUpdated=True, UpdateSourceTrigger=PropertyChanged}">
<ListBox.Resources>
<DataTemplate DataType="{x:Type m:UnitOrderLine}">
<v:OrderLine />
</DataTemplate>
<DataTemplate DataType="{x:Type m:AccessoryOrderLine}">
<v:OrderLine>
<v:OrderLine.ContextMenu>
<ContextMenu>
<MenuItem Header="Pack 1" IsCheckable="False">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<cmd:EventToCommand Command="{Binding ElementName=root, Path=DataContext.PackAccessory }" PassEventArgsToCommand="True" />
</i:EventTrigger>
</i:Interaction.Triggers>
</MenuItem>
</ContextMenu>
</v:OrderLine.ContextMenu>
</v:OrderLine>
</DataTemplate>
</ListBox.Resources>
</ListBox>
I've also tried to use "TemplatedParent" and then I get access to my "OrderLine" DataContext, but I cant get one step further back to my "MainWindowModel".
http://www.thomaslevesque.com/2011/03/21/wpf-how-to-bind-to-data-when-the-datacontext-is-not-inherited/
Found a solution to my problem :)
Found a solution. Updated my original post with the link to my solution.
Its not issue with the DataTemplate. Binding with ElemetName works in all cases except in the case of ContextMenu since it does not lies in the same visual tree as of your window. However, there is one hack where you can use the PlacementTarget property of your context menu.
For details refer to this link - http://social.msdn.microsoft.com/Forums/nl/wpf/thread/526ab350-8788-4bc6-a98a-1e4dee6ad33a
It contains exactly what you are trying to achieve here.
Seems like here are answers for your question:
ElementName Binding from MenuItem in
ContextMenu
WPF MenuItem.Command binding to
ElementName..
I'm trying to bind to a property of a container from inside a DataTemplate. A simplified version of my markup looks like:
<Grid>
<Grid.Resources>
<DataTemplate DataType="{x:Type myCustomItem}">
<!--Visual stuff-->
<StackPanel>
<StackPanel.ContextMenu>
<ContextMenu>
<MenuItem Header="Add Item"
Command="{Binding myCustomItemsICommand}"
CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type CustomContainerType}}, Path=ContainerProperty}"/>
</ContextMenu>
</StackPanel.ContextMenu>
</StackPanel>
</DataTemplate>
</Grid.Resources>
<CustomContainerType/>
</Grid>
My approach is based on this post but it doesn't seem to be working. The issue seems to arise from the placement of the ContextMenu within the visual tree. Basically I am trying to bind the Command to the DataContext of the DataTemplate but bind the CommandParameter to a DataContext outside the DataTemplate.
ContextMenus are not in the same visual tree as the rest of the controls, there are a few questions regarding how to do bindings accross that boundary but this might be somewhat difficult without specifying names.
ElementName fails as well because of the lacking tree connection, but you could use x:Reference in the Binding.Source instead.