I have a combobox in wpf which is bound to a List<string>. All works well, but now for some reason I need to bind to an item template. The XAML for the combo box is
<ComboBox ItemsSource="{Binding Tracks}" SelectedItem="{Binding SelectedTrack}">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding **WhatShouldBeHere**}"></TextBlock>
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
If my data source is a custom collection then binding is easy, I should just pass the property name from custom collection, but as the binding source is a list of string, what should the binding property be?.
It should be
<TextBlock Text="{Binding}"/>
which is equivalent to
<TextBlock Text="{Binding Path=.}"/>
See the Remarks section on the Binding.Path MSDN page for further details.
Related
I have a Data Grid that is bound to a object of type MyStaff. Apart from other properties MyStaff contains a column named LookupID. Now, in my ViewModel I have a collection Named Lookups that have a description for each LookupID.
I have a Template column that has a Textblock in Cell Template and Combobox in CellEdit Template. How do I bind the Textblock so that it dsiplays the description from ComboBox based on LookupID.
I know it would be pretty simple if the datacontext for both the Textblock and ComboBox were simple but that is not the case.
I have tried this but this doesn't work. Any suggestions? Also would appreciate any information on how to best use different Data Context for different controls in Silverlight. For this I have added a static resource pointing to the ViewModel Class.
<sdk:DataGridTemplateColumn Header="Action Point"
Width="500"
CanUserReorder="False"
HeaderStyle="{StaticResource dthFull2}"
IsReadOnly="False">
<sdk:DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock
Text="{Binding ElementName=LookupList,
Path=SelectedItem.Description}"
MinHeight="24"
VerticalAlignment="Top"
Padding="2"
TextTrimming="WordEllipsis"/>
</DataTemplate>
</sdk:DataGridTemplateColumn.CellTemplate>
<sdk:DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<my:AutoCompleteComboBox x:Name="LookupList"
FilterMode="Custom" Margin="2,0,0,0"
SelectedValue="{Binding LookupID, Mode=TwoWay}"
SelectedValuePath="LookupID"
ItemsSource="{Binding Path=AnalysisLookupList.Values,
Source={StaticResource ViewModel}}"/>
</DataTemplate>
</sdk:DataGridTemplateColumn.CellEditingTemplate>
</sdk:DataGridTemplateColumn>
I'm just starting with wpf/vmmv. I've seen examples of binding collections to list boxes. Example: in xaml , in code-behind (e.g. Page) "DataContext = collection.. ".
My view model has more properties than just a single collection that need to be bound to a view. Therefore I'd like to set the view model as DataContext for the view and then, in xaml, bind the view model's collection to a ListBox. Assuming that my view model is set as DataContext and it has a property called 'Customers', what is the correct way of binding the property to a ListBox in xaml?
I tried but it does not work.
Thanks.
Do you mean 'how do you bind a collection to a 'ListBox'? You would do that like this:
<ListBox ItemsSource="{Binding Customers}" />
Or this:
<ListBox ItemsSource="{Binding Path=Customers}" />
If you want to bind the internal values of each instance of the Customer class, you would do something like this:
<ListBox ItemsSource="{Binding Customers}" >
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}" />
<TextBlock Text="{Binding Age}" />
<TextBlock Text="{Binding EyeColour}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I guess you want to display the property "Customers", what you have to do is define ItemTemplate of ListBox, define DataTemplate inside ItemTemplate, and binding Customers to a control, just like below:
<ListBox ItemsSource="{Binding}" >
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=Customers}"/>
......something else you want display
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I am going crazy trying to figure this out without success.
I have a DependencyObject, ("UserObject"). It has a "DataItems" DependecyProperty that is an ObservableCollection. "UserDefiniton" is a DependencyObject with a DependencyProperty of "Data". Data has two properties: DataType (an enumeration) and Value (a string).
I am trying to define a ListBox in XAML that uses the "DataItems" property as its ItemsSource. In the ItemTemplate, I have several different controls. For simplicity of this issue, I am using a CheckBox and a TextBox. I want CheckBox to be available and visible when DataType is 0, while I want the TextBox to be available and visible when the DataType is 1. Only one control can be available and visible at a time.
This works:
<ListBox
ItemsSource={Binding DataItems, Mode=OneWay}>
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<CheckBox
Visibility="{Binding Path=Data.DataType, Mode=OneWay, Converter={StaticResource VisibilityConverter}, ConverterParameter=0}"
IsChecked="{Binding Path=Data.Value, Mode=TwoWay, Converter={StaticResource StringToBoolean}}" />
<TextBox
Visibility="{Binding Path=Data.DataType, Mode=OneWay, Converter={StaticResource VisibilityConverter}, ConverterParameter=1}"
Text="{Binding Path=Data.Value, Mode=TwoWay}" />
</StackPanel>
</DataTemplate>
<Listbox.ItemTemplate>
</ListBox>
The problem is that even though only one is visible, both are fighting over the Data.Value property (the boolean of the checkbox will show in the textbox, even though the checkbox is hidden).
Basically, though, the binding in this case is working--but the implementation is incorrect.
So, I switched to using Templates. The problem I am having is that I can't get the binding to work.
This is the code that I have for the Template. The Template selector is working correctly, but the Text property of the TextBox and the IsChecked property of the checkbox are not binding to Data.Value:
<DataTemplate x:Key="TextBoxItem">
<TextBox
Text="{Binding Path=Data.Value, Mode=TwoWay}" />
</DataTemplate>
<DataTemplate x:Key="CheckBoxItem">
<CheckBox
IsChecked="{Binding Path=Data.Value, Mode=TwoWay, Converter={StaticResource StringToBoolean}}" />
</DataTemplate>
...
<ListBox
ItemsSource={Binding DataItems, Mode=OneWay}>
<ListBox.ItemTemplate>
<DataTemplate>
<ContentControl
Content="{Binding Path=Data.DataType, Mode=OneWay}"
ContentTemplateSelector="{DynamicResource UserDefinitionTemplateSelector}"/>
</DataTemplate>
<ListBox.ItemTemplate>
</ListBox>
So how do I fix the binding?
Content should be set to {Binding}, since the Content will be the DataContext of the data-templates, hence you should just pass on the current DataContext. If you need to pass specific data to the template selector you can just drill down in the whole object.
There also is a template selector on the level of the ListBox, so you do not really need the internal ContentControl.
(You might also be interested in generic methods of debugging data bindings.)
I have the following xaml code:
<ListBox Foreground="{Binding MyColor, Converter={local:ColorConverter}}" ItemsSource="{Binding LogCollection, Mode=TwoWay}" Grid.Row="1">
</ListBox>
This changes the foreground color for the entire listbox, so I modified the code in this way:
<ListBox ItemsSource="{Binding LogCollection, Mode=TwoWay}" Grid.Row="1">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Foreground="{Binding MyColor, Converter={local:ColorConverter}}" Text="{Binding}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
In this way I wanted to set the foreground for an item instead for the entire listbox, but it is not working. How do I find the right datacontext ? MyColor is a property on my MainViewModel.
LATER EDIT WITH THE SOLUTION
Jens's answer was the one that showed me where I was wrong. Instead of storing simple message log strings in the ObservableCollection, I created a new class (LogItems) which contains a Message and a Color members. Now the LogCollection is typeof LogItems instead of strings.
I populate the listbox with the following code in my viewmodel:
LogItems logitem = new LogItems(myMessage, myColor);
LogCollection.Insert(0, logitem);
And the view has the following form. Also it doesn't require anymore to use RelativeSource, because the datacontext is the same.
<ListBox ItemsSource="{Binding LogCollection, Mode=TwoWay}" Grid.Row="1">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Foreground="{Binding Path=Color, Converter={local:ColorConverter}}" Text="{Binding Path=Message}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Thank you all for your answers which lead me to this solution.
The DataContext of generated container in a listbox is automatically set to the corresponding item, therefore your Binding does not find the Property MyColor. You need to use a RelativeSource binding to bind to the DataContext of the containing list:
<TextBlock Foreground="{Binding DataContext.MyColor,
RelativeSource={RelativeSource
Mode=FindAncestor,
AncestorType={x:Type ListBox}},
Converter={local:ColorConverter}}"
Text="{Binding}"/>
Given a silverlight datagrid with RowDetailsVisibilityMode="VisibleWhenSelected", on clicking a row in the datagrid, how do you set or bind the controls in the RowDetailsVisibilityChanged() event?
<data:DataGrid.RowDetailsTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="a" x:Name="_txt" />
<ListBox x:Name="_lst"></ListBox>
</StackPanel>
</DataTemplate>
</data:DataGrid.RowDetailsTemplate>
You don't need to code the rowsvisibilitychanged event, Silverlight will do the binding for you automatically if you set up binding in your data template. Simply use {Binding col_name}.
A simplified example, binding happens automatically as user clicks a row.
<sdk:DataGrid RowDetailsVisibilityMode='VisibleWhenSelected'
ItemsSource='{Binding ElementName=ld_linkDomainDataSource, Path=Data}'>
<data:DataGrid.RowDetailsTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text='Link Name: '/>
<TextBox Text='{Binding link_name}'/> <-- column from ItemsSource
</StackPanel>
</DataTemplate>
</data:DataGrid.RowDetailsTemplate>