I have a list of transactions that I am loading into an ItemsControl but I want to show the UserId from my viewmodel in each row/transaction. The userId is not in the transaction list, it's a property in the viewmodel I am trying to access but it seems everything I've tried doesn't work and I don't know why. All I get is a blank column value. (yes, I did confirm the property is not empty. even hardcoded a value and got nothing).
My understanding is I should be able to use the RelativeSource with an AncestorType of Window to access the property. Am I missing something?
<ItemsControl ItemsSource="{Binding Path=MyReportResult.Transactions}" KeyboardNavigation.IsTabStop="False">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid Margin="20 2 0 2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width=".15*"/>
<ColumnDefinition Width=".15*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" TextAlignment="Center" Margin="10 0 20 0" Text="{Binding Path=UserId, RelativeSource={RelativeSource AncestorType={x:Type Window}}}"></TextBlock>
<TextBlock Grid.Column="0" TextAlignment="Center" Margin="10 0 20 0" Text="{Binding Path=Amount}"></TextBlock>
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
Your RelativeSource binding tries to find the property in the parent Window, although it is in the Window's DataContext.
The following should work, provided that the UserId property is in the same view model class as MyReportResult:
<TextBlock Text="{Binding Path=DataContext.UserId,
RelativeSource={RelativeSource AncestorType=ItemsControl}}"/>
Only WPF supports RelativeSource because it's not strictly necessary. It's less fragile to use ElementName instead like so:
First, give an x:Name="something" to your top level object or its child (usually a Grid).
Text="{Binding Path=DataContext.UserId, Element=something}"
Related
I got a datatemplate
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<ui:UniformWrapPanel />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Border MouseUp="ItemBorder_MouseUp" Name="ItemBorder" CornerRadius="10" BorderBrush="Black" BorderThickness="1" Margin="3" Background="{Binding Converter={StaticResource RescuerColorConverter}}">
<StackPanel Orientation="Vertical" Margin="3">
<TextBlock FontWeight="Bold" FontSize="20" Text="{Binding Path=Identifier}" HorizontalAlignment="Center" />
<TextBlock FontSize="16" Text="{Binding Converter={StaticResource RescuerNameConverter}}" HorizontalAlignment="Center" />
</StackPanel>
</Border>
</DataTemplate>
</ItemsControl.ItemTemplate>
Which displays a list of people and their identifiers:
+--------+
| 6969 |
| Name |
+--------+
I can get the event from the box if i set MouseUp on the Border control but how do I get the values from the textblocks ?
Thanks.
The event handler has a 'sender' parameter which is the object with which the event originated. This will let you get your hands on the instance of Border that you want. Then there are two possibilities:
1) if you're using data binding, the Border's DataContext should be the item for which the DataTemplate was created.
2) if you're not using data binding, you can dig into the visual tree of the Border and locate the TextBlocks that way.
Personally I'd really prefer option 1, however I tend to use neither as I would wire up this kind of thing using Caliburn Micro's actions which let me pass the datacontext as a parameter to a method on the ViewModel.
The DataContext is the object which holds the data, otherwise the bindings would not work, just cast it and get what you need.
var data = (MyDataClass)(sender as Border).DataContext;
// Do stuff with data.Identifier etc.
I'm trying to implement something quite simple but I'm on my first steps in WPF and I'm having some problems. I have a class called Component which has a property called Vertices. Vertices is a generic List of type Point. What I want is to bind the vertices property to a listbox. This is easy by using this code in my XAML in the listbox declaration:
ItemsSource="{Binding Path=Component.Vertices, Mode=OneWay, Converter={StaticResource verticesconverter},UpdateSourceTrigger=PropertyChanged}"
The tricky part is when I try to create a datatemplate for the listbox. I want each row of the listbox to display a textbox with the values of the Vertex (Point.X, Point.Y) and a button to allow me to delete the item. Could you help me on the datatemplate definition. The code below doesn't work to bind the X,Y values into two separate textboxes. Could you point me on the mistake and why nothing is displayed in the textboxes?
<ListBox ItemsSource="{Binding Path=Component.Vertices, Mode=OneWay,UpdateSourceTrigger=PropertyChanged}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" Margin="0,10,0,0">
<TextBox Text="{Binding X}" MinWidth="35" MaxWidth="35"/>
<TextBox Text="{Binding Y}" MinWidth="35" MaxWidth="35"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
/ListBox>
Something like this:
<ListBox ... Grid.IsSharedSizeScope="True">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition SharedSizeGroup="A"/>
<ColumnDefinition SharedSizeGroup="B"/>
<ColumnDefinition SharedSizeGroup="C"/>
</Grid.ColumnDefinitions>
<Grid.Children>
<TextBlock Grid.Column="0" Text="{Binding X}" Margin="5"/>
<TextBlock Grid.Column="1" Text="{Binding Y}" Margin="5"/>
<Button Grid.Column="2" Tag="{Binding}" Margin="5" Click="Button_Click" Content="Remove"/>
</Grid.Children>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Event handler:
private void Button_Click(object sender, System.Windows.RoutedEventArgs e)
{
Button senderB = (Button)sender;
Point pt = (Point)senderB.Tag;
Collection.Remove(pt);
}
Note: Your list in the GUI will not get updated unless your bound collection implements INotifyCollectionChanged (Standard-implementation you can use: ObservableCollection<T>)
Edit: Common binding-fail causes:
1. Bound source is not a public property -> make it one
2. Binding path is not absolute and there is no DataContext to start from
-> Set DataContext of your window in the constructor to itself (this) or...
-> Set ElementName in the Binding to the name of your window if that is where your property is
Edit2: If your collection consists of Vertices and if your Vertex class contains a point with the property-name Point you need to change the bindings to {Binding Point.X} and {Binding Point.Y}, post more code next time please.
I have a really nasty problem with bindings. I know that there are other topics regarding binding itmes inside itemtemplate to datacontext of an object outside the template. However, this just won't work, i.e. the first textblock display 'Test' as desired whereas the same textbox inside the itemtemplate shows nothing.
<TextBlock Text="{Binding DataContext.Test, ElementName=myList}"/>
<ItemsControl x:Name="myList" ItemsSource="{Binding AllItems}"
Margin="0,0,0,0" VerticalAlignment="Top" HorizontalAlignment="Center">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<toolkit:WrapPanel Orientation="Horizontal"
ItemHeight="170" ItemWidth="140"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel>
<Image x:Name="{Binding KeyName}"
Source="{Binding ImagePath}"
Width="128"
Height="128">
</Image>
<TextBlock Text="{Binding DataContext.Test, ElementName=myList}"/>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
I would appreciate some help here folks as this is really a problem for me.
Inside the itemtemplate, the binding is initialized to the context of the current item in AllItems.
Update
Outside of the ItemTemplateyour bindings are relative to the DataContext of the page.**
Once inside an ItemTemplate then bindings are limited to the scope of the item specifically being evaluated at that time.
So, if we assume the following (based on the code in your question):
<ItemsControl x:Name="myList" ItemsSource="{Binding AllItems}" >
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock x:Name="tb1"
Text="{Binding DataContext.Test, ElementName=myList}"/>
<TextBlock x:Name="tb2" Text="{Binding KeyName}"/>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
tb1 cannot access the DataContext object directly.
tb2 cann access KeyName - assuming that whatever object AllItems is an IEnumerable of contains a property with that name.
As I understand it, inside an itemtemplate, the item past from the enumeration controls the binding source and this can't be overridden (by setting ElementName or otherwise).
If you need the value from Test in every object in your enumeration then you'll need to add it as a property of the object in the enumeration.
I'm sure someone more knowledgeable than me could explain why this is or give a better explanation but that's the gist of it.
** Assuming no other nesting of ItemsControls (or equivalent)
I have a template column in a DataGrid:
<sdk:DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" VerticalAlignment="Center" >
<TextBlock Text="{Binding Name,ElementName=rsAllSkills}"/>
</StackPanel>
</DataTemplate>
</sdk:DataGridTemplateColumn.CellEditingTemplate>
And in the same xaml file, I have
<riaControls:DomainDataSource QueryName="GetSkillsQuery" AutoLoad="True" x:Name="rsAllSkills">
<riaControls:DomainDataSource.DomainContext>
<domain:XXXX context/>
</riaControls:DomainDataSource.DomainContext>
</riaControls:DomainDataSource>
The DataSource has loaded everything successfully for sure, if I put that TextBlock out side of the DataGrid, it works; but inside the DataGrid, it doesn't load even the Name of rsAllSkills....
Could anybody give me a hint, thank you so much.
Have a dummy converter and check the binding.
What I guess is, the DataTemplate inside the CellEditingTemplate would receive the parent's DataContext, ie., DataGrid's DataContext. So, to work around this you can do one thing.
1) Bind the rsAllSkills to the Tag Property of DataGridTemplateColumn.
2) Now, Bind the TextBlock's Text property with the Tag property like,
<sdk:DataGridTemplateColumn Tag="{Binding Name,ElementName=rsAllSkills}">
<sdk:DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" VerticalAlignment="Center" >
<TextBlock Text="{Binding Tag}"/>
</StackPanel>
</DataTemplate>
</sdk:DataGridTemplateColumn.CellEditingTemplate>
</sdk:DataGridTemplateColumn>
I have a TreeView which has three levels.
Lets say its a league, division and team TreeView.
Now, when I select each of the items in the tree, I would like to see detailed information about it.
Whats the best way to achieve this?
Since Grid doesn't items (like a ListBox), I can't just set its ItemsSource and make a DataTemplate...
I thought about using a ListBox which will contain only the selected item but this seems to be very bad...
Thanks.
You first define the 3 DataTemplates for your league, division and team classes. After, you bind the TreeView to the root of your objects. Your League and Division classes should have a Children property that returns the children. All your classes should have a Name property.
Then when you want to show a single object, use the ContentPresenter, and the bind its content to the SelectedItem if the TreeView.
For example:
<StackPanel>
<StackPanel.Resources>
<DataTemplate DataType="{x:Type your_namespace:League}">
<StackPanel Orientation="Vertical">
<TextBlock Text={Binding Name}/>
<.../>
<StackPanel>
</DataTemplate>
<DataTemplate DataType="{x:Type your_namespace:Division}">
<StackPanel Orientation="Vertical">
<TextBlock Text={Binding Name}/>
<.../>
<StackPanel>
</DataTemplate>
<DataTemplate DataType="{x:Type your_namespace:Team}">
<StackPanel Orientation="Vertical">
<TextBlock Text={Binding Name}/>
<.../>
<StackPanel>
</DataTemplate>
</StackPanel.Resources>
<TreeView x:Name="_tree" ItemsSource="{Binding RootOfYourItems}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Children}">
<TextBlock Text={Binding Name}/>
</HierarchicalDataTemplate>
</TreeView>
<ContentPresenter Content="{Binding Path=SelectedItem, ElementName=_tree}" />
</StackPanel>
This code was not tested or compiled, it just provided as an example.
I would create a viewmodel with properties for the tree structur, the current selection and the details to the current selection.
The tree struct is one-way bound to the treeview, the SelectedItem from the treeview is OneWayToSource bound to the current selection property (due to the limitations of the property). This property changes the list of child items once the current selection changes, and the child items are bound to the listbox displaying them.