I've built a WPF based Treeview with
Item
-Subitem
If Subitem is selected, I would like to display also Properties of Item.
<StackPanel Grid.Column="2" DataContext="{Binding ElementName=myTreeView, Path=SelectedItem}">
<TextBox Text="{Binding Path=Name, Mode=TwoWay}" />
<TextBox Text="{Binding RelativeSource={???} Path=Name, Mode=TwoWay}" />
</StackPanel>
I guess I need to use a RelativeSource statement, but not quite sure how to do so.
{Binding RelativeSource={RelativeSource AncestorType={x:Type typeOfAncestor}}, Path=Name, Mode=TwoWay}
JesseJames has given you the correct way to use RelativeSource but the best you will be able to do with RelativeSource is bind to the TreeViewItem itself, which is just the container for your data object i.e ViewModel, meaning you won't be able to access your data objects properties(easily).
I think in this case binding to the container object would break the View-ViewModel approach you are using. Your best bet would be to create a Parent object within your ViewModel and bind to that object. So that now each object in your collection has a reference to it's parent which can now be bound to directly.
<StackPanel Grid.Column="2" DataContext="{Binding ElementName=myTreeView, Path=SelectedItem}">
<TextBox Text="{Binding Path=Name, Mode=TwoWay}" />
<TextBox Text="{Binding Parent.Name}" />
</StackPanel>
Also note that the SelectedItem property returns your data object and not the container.
I looked at your code, try binding simply to Name. It appears that your data context should already be set to the TreeViewItem due to the following line: <StackPanel Grid.Column="2" DataContext="{Binding ElementName=myTreeView, Path=SelectedItem}">. The RelativeResource binding is probably looking further up the logical tree and that's why your binding is failing.
Related
Ok so this is kinda hard to explain. I have a view which has a tree and has a form. The tree is bound to 2 different observable collections.
<TreeView FontFamily="Calibri" FontSize="16" Name="tree" Margin="3" Grid.Row="1" Grid.Column="0" Height="950" VerticalAlignment="Top" Grid.ColumnSpan="2"
ItemsSource="{Binding Path=Org, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" SelectedItemChanged="tree_SelectedItemChanged" >
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Path=Org_Sredstva}">
<TextBlock Text="{Binding Path=Organizacije_Naziv}"/>
<HierarchicalDataTemplate.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=Ossr_Naziv}"/>
</DataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
Now then next to the tree there is a form. And the form is supposed to be bound to a third observable collection that changes depending on selecteditem of tree.
<Grid Grid.Row="2" Grid.Column="2" Margin="5" DataContext="{Binding ElementName=tree, Path=SelectedItem}">
As you can see the binding is to the tree which is bound to a different observable collection.
<extToolkit:WatermarkTextBox x:Name="RadnoVrijeme" Grid.Row="1"
Grid.Column="1"
Grid.ColumnSpan="2"
HorizontalAlignment="Left"
VerticalAlignment="Bottom"
Width="100"
Height="25"
Padding="3"
Margin="3"
AcceptsReturn="True"
Validation.ErrorTemplate="{StaticResource ValidationTemplate}"
Validation.Error="Validation_Error">
<extToolkit:WatermarkTextBox.Watermark>
<StackPanel Orientation="Horizontal">
<TextBox Text="Radno Vrijeme" Margin="4,2,2,0" FontWeight="Regular" Foreground="Silver" BorderThickness="0"/>
</StackPanel>
</extToolkit:WatermarkTextBox.Watermark>
<extToolkit:WatermarkTextBox.Text>
<Binding Path="Opr_RadnoVrijeme" UpdateSourceTrigger="PropertyChanged" NotifyOnValidationError="True">
<Binding.ValidationRules>
<validation:InputLenghtRule MinLength="10" MaxLength="250" ValidatesOnTargetUpdated="True"/>
</Binding.ValidationRules>
</Binding>
</extToolkit:WatermarkTextBox.Text>
</extToolkit:WatermarkTextBox>
This is a textbox and it is bound to a property on the third collection but it doesn't work obviously because that collection is never set as itemssource anywhere.
The workaround I found is to in codebehind set every textbox individually so
this.View.RadnoVrijeme.Text = opr.Opr_RadnoVrijeme;
Where the left side of the equation is the text property of the textbox and the right side is the collection.property. This works but I don't like it and was hoping there was a way to actually bind this?
You should definetely have a look at MVVM. It utilize modular design, where your View is consisting of multiple Views controlled by ViewModels. Then it's easy to solve any kind of dependency (relation? selection?) problem.
In your case you are trying to bind to SelectedItem directly, while in MVVM you will handle selection and then you have possibility to rise notification of related property change, which will cause update of corresponding View element automatically.
Here is a generic example:
ItemVM _selectedItem;
public ItemVM SelectedItem
{
get { return _selectedItem; }
set
{
_selectedItem = value;
OnPropertyChanged();
// trigger update in the view
OnPropertyChanged(nameof(SomeRelatedProperty));
}
}
// bind TextBlock.Text to that property
public string SomeRelatedProperty
{
get
{
// some logic based on selected item
if(SelectedItem.SomeProperty == SomeValue)
return "a";
...
return "b";
}
}
The cooler thing if SelectedItem already provides value as one of property (because it's a ViewModel), then assuming all ViewModels implement INotifyPropertyChanged you can simply bind to that property directly and whenever selected item is changed the view will be updated to display that property too:
<TextBlock Text="{Binding SelectedItem.SomeProperty} ... / >
As for error you are getting:
System.Windows.Data Error: 40 : BindingExpression path error: 'Opr_RadnoVrijeme' property not found on 'object' ''Organizacije' (HashCode=23451234)'. BindingExpression:Path=Opr_RadnoVrijeme; DataItem='Organizacije' (HashCode=23451234); target element is 'WatermarkTextBox' (Name='RadnoVrijeme'); target property is 'Text' (type 'String')
Try binding (pretty unsure, you didn't provide ViewModels to figure that out):
<WatermarkTextBox Text="{Binding SelectedItem.Opr_RadnoVrijeme, RelativeSource={RelativeSource FindAncestor, AncestorType=TreeView}}" ... />
To display items on Telerik:RadGridView usually I use DataContext="{Binding [someViewModel]}" and ItemSource="{Binding objectList, Mode=TwoWay}".
and for my column I'll access the objectfield. The overall picture will be something like below:
<telerik:RadGridView DataContext="{Binding [someViewModel]}"
ItemSource="{Binding objectList, Mode=TwoWay}">
<telerik:RadGridView.Columns>
<telerik:GridViewDataColumn>
<telerik:GridViewDataColumn.CellTemplate>
<DataTemplate>
<CheckBox IsEnabled="{Binding enabledVar}"
IsChecked="{Binding isChecked, Mode=Twoway}"
</DataTemplate>
</telerik:GridViewDataColumn.CellTemplate>
</telerik:GridViewDataColumn>
</telerik:RadGridView.Columns>
</telerik:RadGridView>
Imagine there will be 10 items in objectList. Each of the item in objectList will have a variable isChecked which to manipulate the checkbox IsChecked property.
I have another variable in the same viewmodel named enabledVar which to control the ten checkbox IsEnabled property. enabledVar is not part of the objectList but I couldn't get the value. May I know how to handle such case?
Updates:
I've found some new direction but not sure if it helps.
<CheckBox IsEnabled="{Binding enabledVar,
RelativeSource={RelativeSource Mode=FindAncestor,
AncestorType=telerik:RadGridView}}"
but then of course, still failed.
Any helps would be very much appreciated.
if using Ancestor you have to bind to DataContext
<CheckBox IsEnabled="{Binding Path=DataContext.enabledVar,
RelativeSource={RelativeSource Mode=FindAncestor,
AncestorType=telerik:RadGridView}}"
Another aproach could be to use element binding set name
<telerik:RadGridView x:Name="myGrid" ...
And then in the celltemplate bind to it
<CheckBox IsEnabled="{Binding Path=DataContext.enabledVar, ElementName=myGrid}"
Hope this helps.
The code suggested in Update will not work because GridViewDataColumn is not part of the Visual tree, and hence can not access DataContext.
You will have to make use of proxy data binding, like suggested here. You can get more examples by searching "wpf proxy databinding".
I am having problems binding a textbox to my viewmodel.
<DataTemplate x:Key="ContentDetail" >
<StackPanel Orientation="Horizontal" Height="500"">
<TextBlock TextWrapping="Wrap" Text="{Binding SelectedCall.CUCODE }" />
</StackPanel>
</DataTemplate>
I know the binding is fine as I have it also bound outside the datatemplate
DataContext="{Binding HelpdeskViewModel, Source={StaticResource ServiceLocator}}"
dx:ThemeManager.ThemeName="VS2010" SelectedItem="{Binding SelectedCall,UpdateSourceTrigger=PropertyChanged}">
Any pointers would be gratefully accepted.
Edit:
<dxg:GridControl.DetailDescriptor>
<dxg:TabViewDetailDescriptor>
<dxg:TabViewDetailDescriptor.DetailDescriptors>
<dxg:ContentDetailDescriptor ContentTemplate="{StaticResource ContentDetail}" HeaderContent="More Detail" >
</dxg:ContentDetailDescriptor>
</dxg:TabViewDetailDescriptor.DetailDescriptors>
</dxg:TabViewDetailDescriptor>
</dxg:GridControl.DetailDescriptor>
Items within a Template are bound to the current item in the Template (so your datacontext in this scope isn't your window's viewmodel, but the current item).
I assume SelectedCall is a property on your window's viewmodel and not a property on each bound item, so you can't access that. If it's also a property of each model then simply bind to CUCODE, else if it's a single per window item, you'd have to trace back to the ancestor window & bind to the datacontext of the window instead of the one automatically set for you within the context of the Template.
You're probably looking for something like that
<TextBlock Text="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}, Path=SelectedCall.CUCODE }}" />
Is it possible to have multiple ItemSources for a single control?
Given the code below:
<ComboBox Margin="137,101,169,183" ItemsSource="{Binding collection}" SnapsToDevicePixels="True"
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox Command="{Binding CheckCommand}" IsChecked="{Binding IsChecked}" Content="{Binding Name}"/>
<TextBlock Text="" />
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
The TextBlock within the ComboBox DataTemplate requires data from another property within the VM than that of the ComboBox. How can this be achieved?
Thanks.
You can use RelativeSource-FindAncestor to reach up the visual tree and grab a different DataContext.
For example (assuming the command is what you want):
Command=”{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ComboBox}}, Path=CheckCommand}”
This should also serve as a good resource.
Edit: Typo and resources.
If i remember correctly, DataTemplates run within their own scope and cannot directly use ElementNames defined outside the DataTemplate. You could however get around it by using StaticResource and referring to that directly from TextBlock inside the template.
I haven't tried Ragepotatos's approach to go outside DataTemplate scope but would love to know if that works out for you too.
I have a listbox and I have set the itemstemplate as shown below.
XAML:
<ListBox ItemsSource="{Binding DataList}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox x:Name="CheckBox" HorizontalAlignment="Center" VerticalAlignment="Center" />
<TextBlock x:Name="TextBlock" Text="{Binding Title}" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="10,0,0,10" FontSize="26.667" TextWrapping="Wrap"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I want to get which all check box has been selected.Is there any way to get checkbox control for each item so that I can check its IsChecked property.
I can think of a way of binding the IsChecked property.But Is there any other way to do it?
Yes. One way to do is to bind the IsChecked property. And if you are using MVVM, probably that's the right way to do it.
Anyways, if you don't want to go the binding way, and assuming you want to iterate over all items of listbox, and prepare a list of checked items, see if this helps:
WPF - Find a Control from DataTemplate in WPF
If you're already binding to the Title property in the item template then it would certainly make sense to bind to IsChecked, too.
If you really need to, you can walk the visual tree by using the VisualTreeHelper to find the CheckBox instances.
Binding the IsChecked property to a boolean property on your object instance contained within DataList would be the simplest and cleanest way. Alternatively, if you want to avoid code behind, then you could write an attached property.
See also How to access a specific item in a Listbox with DataTemplate?
I bet it cannot be simpler than that:
<ListBox SelectionMode="Multiple" >
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox
IsChecked="{Binding Path=IsSelected, RelativeSource={RelativeSource AncestorType={x:Type ListBoxItem}}}"
Content="{Binding Path=Content, RelativeSource={RelativeSource AncestorType={x:Type ListBoxItem}}}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>