i have this xaml code:
<Window.CommandBindings>
<CommandBinding Command="WpfApplication1:MainCommands.Search" Executed="Search"/>
</Window.CommandBindings><Grid>
<StackPanel>
<ListView ItemsSource="{Binding SearchContext}" />
<TextBox Text="{Binding LastName}">
<TextBox.InputBindings>
<KeyBinding Key="Enter" Command="{x:Static WpfApplication1:MainCommands.Search}" />
</TextBox.InputBindings>
</TextBox>
</StackPanel>
The Search-Method looks like:
private void Search(object sender, RoutedEventArgs e)
{
SearchContext = new ObservableCollection<string>(list.Where(element => element.Name == LastName).Select(el => el.Name).ToList());
}
MainCommands:
public static class MainCommands
{
public static RoutedCommand Search = new RoutedCommand();
}
But if i press enter while focus is in textbox, the binding is´nt computet and LastName is Null. What is the reason? How can I avoid this? Or is it possible to explicit call the binding operation?
Thank you in advance.
Set the UpdateSourceTrigger property to PropertyChanged:
<TextBox Text="{Binding LastName, UpdateSourceTrigger=PropertyChanged}">
This will cause the source property (LastName) to be set immediately: https://msdn.microsoft.com/en-us/library/system.windows.data.updatesourcetrigger(v=vs.110).aspx
As I can see your Window is a view-model for it. I recommend you to use MVVM and have separate class for view-model where you can place desired ICommand and use CommandParameter on KeyBinding:
<TextBox x:Name="searchBox"
Text="{Binding LastName}">
<TextBox.InputBindings>
<KeyBinding Key="Enter"
Command="{Binding Path=SearchCommand}"
CommandParameter="{Binding Path=Text, ElementName=searchBox}" />
</TextBox.InputBindings>
</TextBox>
Related
I have buttons "ADD" and "DEL", but "DEL" does not work. What is wrong?
count in my ObservableCollection<User> was changed but ListBox does not
sample project: https://github.com/Veselov-Dmitry/MyQuestion
view:
<StackPanel>
<Button Content="ADD"
Command="{Binding AddUsers_OASUCommand}"
CommandParameter="">
</Button>
<ListBox ItemsSource="{Binding Users_OASU}">
<ListBox.ItemTemplate>
<DataTemplate>
<WrapPanel>
<TextBlock Text="{Binding Name}" />
<TextBlock Text="{Binding Login}" />
<Button Content="DEL"
Command="{Binding DelUsers_OASUCommand}"
CommandParameter="{Binding Path=Content,
RelativeSource={RelativeSource Mode=FindAncestor ,
AncestorType={x:Type ListBoxItem}}}">
<Button.DataContext>
<local:ViewModel />
</Button.DataContext>
</Button>
</WrapPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
I set datacontext in constructor MainView
viewvmodel:
class ViewModel
{
public event PropertyChangedEventHandler PropertyChanged;
public ObservableCollection<User> Users_OASU{get; set;}
public ICommand AddUsers_OASUCommand{get; set;}
public ICommand DelUsers_OASUCommand{get; set;}
public ViewModel()
{
Users_OASU = new ObservableCollection<User>(GetUsers());
AddUsers_OASUCommand = new Command<object>(arg => AddUsers_OASUMethod());
DelUsers_OASUCommand = new Command<object>(arg => DelUsers_OASUMethod(arg));
}
private void DelUsers_OASUMethod(object arg)
{
User find = Users_OASU.Where(x => x.Login == (arg as User).Login).FirstOrDefault();
Users_OASU.Remove(find);
}
private void AddUsers_OASUMethod()
{
Users_OASU.Add(new User("52221", "John X."));
}
private List<User> GetUsers()
{
List<User> list = new List<User>();
list.Add(new User("52222", "John W."));
list.Add(new User("52223", "John Z."));
list.Add(new User("52224", "John A."));
list.Add(new User("52225", "John M."));
return list;
}
}
"count in my ObservableCollection was changed but ListBox does not" - you have multiple instances of ViewModel, count was changed, but not in the collection which is displayed
you need to setup DataTemplate correctly to avoid that
first, each Button will get User object for DataContext (it will be provided by ListBox from ItemsSource). You mustn't declare new <Button.DataContext>
second, DelUsers_OASUCommand is declared in a ViewModel class, it is accessible on ListBox level, from DataContext. Change binding path accordingly.
<DataTemplate>
<WrapPanel>
<TextBlock Text="{Binding Name}" />
<TextBlock Text="{Binding Login}" />
<Button Command="{Binding DataContext.DelUsers_OASUCommand,
RelativeSource={RelativeSource AncestorType=ListBox}}"
CommandParameter="{Binding Path=Content,
RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem}}}"
Content="DEL" />
</WrapPanel>
</DataTemplate>
additionally I would change DelUsers_OASUMethod to accept User as argument
private void DelUsers_OASUMethod(object arg)
{
Users_OASU.Remove(arg as User);
}
and pass CommandParameter like this:
CommandParameter="{Binding Path=.}"
or the same, but shorter:
CommandParameter="{Binding}"
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.
I have a Textbox and for that textbox I have attached a keydown event. Everything is working fine but I just noticed that when i'm pressing the 'Backspace' and 'Delete' Key, the binding command is not being called.
My View xaml file :-
<TextBox x:Name="textBox" Width="500" Text="{Binding TextBoxText, UpdateSourceTrigger=PropertyChanged}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="KeyDown">
<cmd:EventToCommand Command="{BindingPath=TextBoxKeyDownEvent}" PassEventArgsToCommand="True" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
My ViewModel cs file :-
//TextBox Key Down Event Handler
private DelegateCommand _textBoxKeyDownEvent;
public ICommand TextBoxKeyDownEvent
{
get
{
if (_textBoxKeyDownEvent == null)
{
_textBoxKeyDownEvent = new DelegateCommand(TextBoxKeyDownEventHandler);
}
return _textBoxKeyDownEvent;
}
set { }
}
Can somebody give me some suggestion
EDIT:
You have to use PreviewKeyDown the it works. KeyDown is not fired on Space and Delete. If you ignore MVVM and put the handler of KeyDown in codebehind it will also fail.
How about binding the Text-Property to a string in you viewmodel?
I build a fast, simple example of my idea.
Result
Text from the TextBox on the left side is simply populated to the Textblock on the right side.
View
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<StackPanel Orientation="Horizontal">
<TextBox Text="{Binding TextBoxValue, UpdateSourceTrigger=PropertyChanged}" Width="250"/>
<StackPanel Orientation="Horizontal">
<TextBlock>"</TextBlock>
<TextBlock Text="{Binding TextBoxValue, UpdateSourceTrigger=PropertyChanged}" />
<TextBlock>"</TextBlock>
</StackPanel>
</StackPanel>
</Window>
ViewModel
public class MainWindowViewModel : INotifyPropertyChanged
{
private string textBoxValue;
public string TextBoxValue
{
get { return textBoxValue; }
set
{
textBoxValue = value;
OnTextBoxValueChanged();
RaisePropertyChanged();
}
}
void OnTextBoxValueChanged()
{
// you logic here, if needed.
}
#region INotifyPropertyChanged implementation
public event PropertyChangedEventHandler PropertyChanged;
void RaisePropertyChanged([CallerMemberName] string propertyName = null)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
you most use PreviewKeyDown event.
Like this:
<EventSetter Event="PreviewKeyDown" Handler="TextBox_PreviewKeyDown"/>
Edit: You are correct - the default behavior is not executed. You should use ec8ors solution, which is much better anyway:
<TextBox x:Name="textBox" Width="500" Text="{Binding TextBoxText, UpdateSourceTrigger=PropertyChanged}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="PreviewKeyDown">
<i:InvokeCommandAction Command="{Binding TextBoxKeyDownEvent, Mode=OneWay}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
Original:
You can use InputBindings to call your command when "special" keys have been pressed:
<TextBox x:Name="textBox" Width="500" Text="{Binding TextBoxText, UpdateSourceTrigger=PropertyChanged}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="KeyDown">
<cmd:EventToCommand Command="{BindingPath=TextBoxKeyDownEvent}" PassEventArgsToCommand="True" />
</i:EventTrigger>
</i:Interaction.Triggers>
<TextBox.InputBindings>
<KeyBinding Command="{Binding TextBoxKeyDownEvent}" Key="Delete" />
<KeyBinding Command="{Binding TextBoxKeyDownEvent}" Key="Back" />
</TextBox.InputBindings>
</TextBox>
WPF has turned on Validation in TextBox by default. How could I propagate a TextBox's Validation.Error up to its ItemsControl if its ItemTemplate is composed of the TextBox ? I want to bind a button's IsEnabled into the Validation.Error on an item in ItemsControl.
<ItemsControl ItemsSource="{Binding}"
x:Name="my_itemsControl">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBox Text="{Binding FirstName}" />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
<Button Content="Save">
<Button.IsEnabled >
<Binding ElementName="my_itemsControl"
Path="(Validation.HasError)" />
</Button.IsEnabled>
</Button>
OK, I finally got a nice solution which uses MVVM pattern.
<UserControl x:Class="MyUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
x:Name="this_control">
<Button Content="Save"
Command="{Binding Path=SaveCommand}"
CommandParameter="{Binding ElementName=this_control}" />
</UserControl>
And the ICommand Property which I bound to on the view-model is like
public ICommand SaveCommand
{
get
{
if (_saveCommand == null)
{
_saveCommand = new RelayCommand(
param => save(),
param => IsValid((DependencyObject)param) // actually the type of param is MyUserControl
);
}
return _saveCommand;
}
}
where the IsValid is based on the fantastic trick
I execute a command on my ViewModel from a TextBox-KeyUp event. The problem I'm facing is that text from the TextBox which binds to a property on the ViewModel, is (still) null when the command is executed.
ViewModel:
private string _myText;
public string MyText
{
get { return _myText; }
set
{
_myText = value;
RaisePropertyChanged("MyText");
}
}
// ... ICommand stuff here
private object HandleMyCommand(object param)
{
Console.WriteLine(MyText); // at this point MyText --> 'old' value, e.g. null
return null;
}}
XAML:
<StackPannel>
<TextBox x:Name="tbTest" KeyUp="TextBox_KeyUp" Text="{Binding MyText, Mode=TwoWay}" />
<Button x:Name="btnTest" Content="Click" Command="{Binding MyCommand}" />
</StackPannel>
Code behind:
private void TextBox_KeyUp(object sender, KeyEventArgs e)
{
if (e.Key == Key.Enter)
{
if (btnTest.Command.CanExecute(null))
{
btnTest.Command.Execute(null);
}
}
}
The binding and command both work. When executing the command the normal way, using the button, the property is set nicely.
Am I not doing this correctly?
Set UpdateSourceTrigger=PropertyChanged as by default MyText will be updated on lost focus:
Text="{Binding MyText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
also, not related to your problem, but you can create InputBinding for TextBox to execute some Command when Enter is pressed:
<TextBox x:Name="tbTest" Text="{Binding MyText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
<TextBox.InputBindings>
<KeyBinding Key="Enter" Command="{Binding MyCommand}"/>
</TextBox.InputBindings>
</TextBox>
Try to change the binding of the text property to:
Text="{Binding MyText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"