Develop Reference

WPF CheckBox Command inside a Listview DataTemplate

My CheckBox Command does not work. I want to pass the SelectedItem of the ListView to the Command when the SelectedItem is checked or unchecked, but the Command does not execute at all. I also suspect my CommandParameter is not configured correctly?
I am pretty sure the problem is because the CheckBox is within a ListView DataTemplate.
Can someone show me how to set this up? I tried to follow examples I found, but nothing seems to work. thanks.
XAML
<ListView x:Name="lvReferralSource" ItemsSource="{Binding ReferralSourceTypeObsCollection}" Style="{StaticResource TypeListViewStyle}">
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<CheckBox x:Name="ckbReferralIsChecked" Content="{Binding Value}" IsChecked="{Binding Active}" Style="{StaticResource CheckBoxStyleBase2}"
Command="{Binding CheckBoxIsChecked}" CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListView}}, Path=SelectedItem}">
</CheckBox>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
CODE
private ICommand _CheckBoxIsChecked;
public ICommand CheckBoxIsChecked
{
get
{
if (_CheckBoxIsChecked == null)
{
_CheckBoxIsChecked = new RelayCommand<object>(ExecuteCheckBoxIsChecked, CanExecuteCheckBoxIsChecked);
}
return _CheckBoxIsChecked;
}
}
public bool CanExecuteCheckBoxIsChecked(object parameter)
{
return true;
}
public void ExecuteCheckBoxIsChecked(object parameter)
{
Mouse.OverrideCursor = Cursors.Wait;
if (parameter != null)
{
//Do Stuff...
}
Mouse.OverrideCursor = Cursors.Hand;
}

Your command should get executed provided that the CheckBoxIsChecked property belongs to the data object where the Value and Active properties are defined.
If it belongs to the view model, you could bind to it using a RelativeSource:
<CheckBox x:Name="ckbReferralIsChecked" Content="{Binding Value}" IsChecked="{Binding Active}"
Style="{StaticResource CheckBoxStyleBase2}"
Command="{Binding DataContext.CheckBoxIsChecked, RelativeSource={RelativeSource AncestorType=ListView}}"
CommandParameter="{Binding}">

Wpf ListView trigger SourceUpdate

How do i trigger the SourceUpdate of my wpf listview?
This is my xaml
<ListView DataContext="{StaticResource vmInstance}" SelectedItem="{Binding selectedItem}" BorderBrush="Beige" BorderThickness="1" ItemsSource="{Binding lstExternal}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged" >
<cmd:EventToCommand Command="{Binding Path=ItemChanged}"
PassEventArgsToCommand="True" />
</i:EventTrigger>
<i:EventTrigger EventName="SourceUpdated">
<cmd:EventToCommand Command="{Binding Path=SourceUpdated}"
PassEventArgsToCommand="True" />
</i:EventTrigger>
</i:Interaction.Triggers>
<ListView.View >
</ListView.View>
</ListView>
ViewModel:
public static RelayCommand SourceUpdated { get; set; }
//on initialize
SourceUpdated = new RelayCommand(SourceUpdateEvent);
public void SourceUpdateEvent()
{
Console.WriteLine("Updated");
}
Why does SourceUpdateEvent doesn't run?
Am I using the wrong event?
Thank you

want to execute a method when the itemsource of the listview is changed or updated
Then bind the ItemsSource property of the ListView to a source property of your view model
<ListView ItemsSource="{Binding YourCollection}" ...>
...and invoke your command in the setter of this source property:
private ObservableCollection<YourType> _sourceCollection;
public ObservableCollection<YourType> SourceCollection
{
get { return _sourceCollection; }
set
{
_sourceCollection = value;
RaisePropertyChanged();
SourceUpdated.Execute(null);
}
}
This is the (only) correct way to solve this using the MVVM pattern.

How do I get double click edit to work on one row in my list view?

I have a simple list view with gridview to display each row.
I added a key binding for delete which is working fine.
<ListView.InputBindings>
<KeyBinding Key="Delete" Command="{Binding Path=DeleteKeyCommand}" CommandParameter="{Binding ElementName=DatabasesLstVw, Path=SelectedItem}"/>
</ListView.InputBindings>
But when I add a Mousebinding for LeftDoubleClick to edit its not firing the command.
<MouseBinding Gesture="LeftDoubleClick" Command="{Binding Path=LeftDoubleClickCommand}" CommandParameter="{Binding ElementName=DatabasesLstVw, Path=SelectedItem}" />
After spending the last two hours trying to figure it out the only thing I have come up with is that its firing the double click on the entire list view and not the listview item???
How do I get double click edit to work on one row in my list view? I am using MVVM I don't want to break that so I cant use code behind to hack it. There must be a way to map the command back to my view model.
Update more code:
<ListView x:Name="DatabasesLstVw" ItemsSource="{Binding Path=ClientDetails.Databases}" ItemContainerStyle="{StaticResource alternatingStyle}" AlternationCount="2" Grid.Row="2" Grid.ColumnSpan="4" VerticalAlignment="Top" >
<ListView.InputBindings>
<KeyBinding Key="Delete" Command="{Binding Path=DeleteKeyCommand}" CommandParameter="{Binding ElementName=DatabasesLstVw, Path=SelectedItem}"/>
<MouseBinding Gesture="LeftDoubleClick" Command="{Binding Path=LeftDoubleClickCommand}" CommandParameter="{Binding ElementName=DatabasesLstVw, Path=SelectedItem}" />
</ListView.InputBindings>

As the referenced answer is missing some code, this is how it should be:
public class AddToInputBinding
{
public static System.Windows.Input.InputBinding GetBinding(DependencyObject obj)
{
return (System.Windows.Input.InputBinding)obj.GetValue(BindingProp);
}
public static void SetBinding(DependencyObject obj, System.Windows.Input.InputBinding value)
{
obj.SetValue(BindingProp, value);
}
public static readonly DependencyProperty BindingProp = DependencyProperty.RegisterAttached(
"Binding", typeof(System.Windows.Input.InputBinding), typeof(AddToInputBinding), new PropertyMetadata
{
PropertyChangedCallback = (obj, e) =>
{
((UIElement)obj).InputBindings.Add((System.Windows.Input.InputBinding)e.NewValue);
}
});
}
Then, in your XAML, you would do something like this:
<Window x:Class="WpfApplication.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication"
Title="Window1" Height="300" Width="300">
<Window.Resources>
<ResourceDictionary>
<Style TargetType="ListViewItem">
<Setter Property="local:AddToInputBinding.Binding">
<Setter.Value>
<MouseBinding Gesture="LeftDoubleClick" Command="{Binding DataContext.ItemDoubleClick,
RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListView}}}"
CommandParameter="{Binding}"/>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
</Window.Resources>
<Grid>
<ListView ItemsSource="{Binding Patients}">
<ListView.View>
<GridView>
<GridViewColumn Header="Test" />
</GridView>
</ListView.View>
</ListView>
</Grid>
In your viewModel, the command definition would be like this:
RelayCommand<string> _ItemDoubleClick;
public ICommand ItemDoubleClick
{
get
{
if (_ItemDoubleClick == null)
{
_ItemDoubleClick = new RelayCommand<string>(this.ItemDoubleClickExecuted,
param => this.ItemDoubleClickCanExecute());
}
return _ItemDoubleClick;
}
}
private bool ItemDoubleClickCanExecute()
{
return true;
}
private void ItemDoubleClickExecuted(string item)
{
//In item you've got the text of double clicked ListViewItem
}
Note that in this sample, the ListView binded ObservableCollection is of type string. If this was other type, you should change the types in the ICommand definitions. Don't forget also to set the Window DataContext to your ViewModel.
Hope this is clearer now.

Delete item from ItemControl

My class is has a ObservableCollection of my viewmodel class and I set the itemsource of the Itemcontrol in xaml as below
<ItemsControl ItemsSource="{Binding ConditionItems}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Expander Background="#FFD0D7EB">
<StackPanel>
<Button Content="Delete" HorizontalAlignment="Right" Width="180" Margin="0,0,12,10" Command="{Binding DeleteItem}" CommandParameter="{Binding}">
</Button> </StackPanel>
</Expander>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
For some reason my DeleteItem is never called.
private RelayCommand _DeleteRule;
private void DoDeleteRule(object item)
{
if (item != null)
{
MessageBox.Show("in del");
}
}
public ICommand DeleteItem
{
get
{
if (_DeleteRule == null)
_DeleteRule = new RelayCommand(o => DoDeleteRule(o));
return _DeleteRule;
}
}
Am I doing anything wrong in xaml?

The ItemsControl is bound using {Binding ConditionItems}, so it expects the DeleteItem command to be inside the subitems of that list. I guess this is not the case, the DeleteItem exists on the ViewModel.
You could bind to the DataContext of the Window for example, where you can find the DeleteItem command. Or create a proxy element.

I found it. My xaml should be
<Button Content="Delete" Command="{Binding DataContext.DeleteItem,
RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type ItemsControl}}}" CommandParameter="{Binding}">
</Button>

Get index of item in bindable collection

In this listbox i display contact names.
<ListBox x:Name="Items" Margin="36,38,78,131">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock x:Name="lol" Text="{Binding Path=ContactName}" Style="{StaticResource PhoneTextSmallStyle}"
Width="Auto" TextAlignment="Center" FontWeight="Bold" Foreground="White" VerticalAlignment="Bottom" TextWrapping="Wrap"/>
<Button x:Name="ShowName">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<cal:ActionMessage MethodName="delete" />
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I get contacts from local DB
public List<FBContacts> listContactDatas { get; set; }
Items = new BindableCollection<FBContacts>();= new BindableCollection<FBContacts>();
public void GetContacts()
{
using(MyDataContext mydb = new MyDataContext(DBConnectionstring))
{
var items = from ContactsList Name in mydb._contacts select Name;
foreach (var toDoItem in items)
{
Items.Add(new FBContacts()
{
ContactName = toDoItem.Name
});
}
}
}
user can delete any contact if he press button.
public void delete()
{
Items.RemoveAt(/* index*/);
}
so how i can get index of choosen contact?

It is easier if you pass the clicked FBContacts to delete method :
<Button x:Name="ShowName">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<cal:ActionMessage MethodName="delete">
<cal:Parameter Value="{Binding}" />
</cal:ActionMessage>
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
Then you can remove by FBContacts object instead of index :
public void delete(FBContacts item)
{
Items.Remove(item);
}

Bind the currently selected item's index to a separate property:
<ListBox x:Name="Items" SelectedIndex="{Binding SelectedListIndex}" Margin="36,38,78,131">
Of course, SelectedListIndex must be defined as property of type int that fires PropertyChanged in the Viewmodel.
Then, you can easily access the selected item's index everywhere within the Viewmodel:
public void delete()
{
Items.RemoveAt(SelectedListIndex);
}