Develop Reference

MVVM Textbox gotFocus binding to a method is not working

I have a method in my view model. How I can bind this method to textbox.gotfocus property.
My XAML part is:
<TextBox Style=
"{StaticResource TextBoxHadnigPanel}"
GotFocus="{Binding GotFocusCustomerNameMethod}"
LostFocus="{Binding LostFocusCustomerNameMethod}"
x:Name="TextBoxCustomerName"
Grid.Row="0"
Grid.Column="1"
MaxLength="16"
Margin="10" />
How to bind this LostFocus and GotFocus properties?
Anyone?
Thanks in advance

You can't bind a method in WPF.
Alternative: You can use a Behavior for a TextBox with MVVM.
You need a reference to System.Windows.Interactivity to achieve this.
public class TextBoxFocusBehavior : Behavior<TextBox>
{
#region Overrides of Behavior
protected override void OnAttached()
{
AssociatedObject.GotFocus += AssociatedObject_GotFocus;
AssociatedObject.LostFocus += AssociatedObject_LostFocus;
base.OnAttached();
}
private void AssociatedObject_LostFocus(object sender, RoutedEventArgs e)
{
//TODO Your LostFocus Method here.
}
private void AssociatedObject_GotFocus(object sender, RoutedEventArgs e)
{
//TODO Your GotFocus Method here.
}
#endregion
}
Xaml:
You need a reference in the xaml file:
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
xmlns:behaviors="clr-namespace:YourNamespace"
<TextBox Style="{StaticResource TextBoxHadnigPanel}"
x:Name="TextBoxCustomerName"
Grid.Row="0"
Grid.Column="1"
MaxLength="16"
Margin="10">
<i:Interaction.Behaviors>
<behaviors:TextBoxFocusBehavior />
</i:Interaction.Behaviors>
</TextBox>

Click event on calendar control

I have added a click event on the calendar control. But with my implementation, this event don't work.
My code in Cal.cs control:
#region click
public static RoutedEvent ClickEvent =
EventManager.RegisterRoutedEvent("Click", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(Cal));
public event RoutedEventHandler Click
{
add { AddHandler(ClickEvent, value); }
remove { RemoveHandler(ClickEvent, value); }
}
protected virtual void OnClick()
{
RoutedEventArgs args = new RoutedEventArgs(ClickEvent, this);
RaiseEvent(args);
}
protected override void OnMouseLeftButtonUp(MouseButtonEventArgs e)
{
base.OnMouseLeftButtonUp(e);
OnClick();
}
#endregion
XAML code :
<Calen:Cal x:Name="Calendar" Margin="0,50,0,0" Click="Calendar_Click"/>
C# code :
private void Calendar_Click(object sender, RoutedEventArgs e)
{
string t = "";
}
I don't found any solution. I don't know why this code don't work correctly.
Can you help me with this problem please ?

You need to set the DataContext to point to the class that contains the code behind.
<UserControl>
DataContext="{Binding RelativeSource={RelativeSource Self}}">
</UserControl>
This is necessary because unfortunately, by default, the DataContext is not set up correctly in WPF.
For more info on DataContext, see ReSharper WPF error: "Cannot resolve symbol "MyVariable" due to unknown DataContext".

Close Window without code-behind in WPF

Is it possible to bind a Button to Close the Window without adding a code-behind event?
<Button Content="OK" Command="{Binding CloseWithSomeKindOfTrick}" />
Instead of the following XAML:
<Button Content="OK" Margin="0,8,0,0" Click="Button_Click">
With the code-behind:
private void Button_Click(object sender, RoutedEventArgs e)
{
Close();
}
Thanks!

If you want close the dialog Window, you can add for Button IsCancel property:
<Button Name="CloseButton"
IsCancel="True" ... />
This means the following MSDN:
When you set the IsCancel property of a Button to true, you create a Button that is registered with the AccessKeyManager. The button is then activated when a user presses the ESC key.
Now, if you click on this Button, or press Esc then dialog Window is closing, but it does not work for the normal MainWindow.
To close the MainWindow, you can simply add a Click handler which has already been shown. But if you want a more elegant solution that would satisfy the MVVM style you can add the attached behavior:
public static class ButtonBehavior
{
#region Private Section
private static Window MainWindow = Application.Current.MainWindow;
#endregion
#region IsCloseProperty
public static readonly DependencyProperty IsCloseProperty;
public static void SetIsClose(DependencyObject DepObject, bool value)
{
DepObject.SetValue(IsCloseProperty, value);
}
public static bool GetIsClose(DependencyObject DepObject)
{
return (bool)DepObject.GetValue(IsCloseProperty);
}
static ButtonBehavior()
{
IsCloseProperty = DependencyProperty.RegisterAttached("IsClose",
typeof(bool),
typeof(ButtonBehavior),
new UIPropertyMetadata(false, IsCloseTurn));
}
#endregion
private static void IsCloseTurn(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue is bool && ((bool)e.NewValue) == true)
{
if (MainWindow != null)
MainWindow.PreviewKeyDown += new KeyEventHandler(MainWindow_PreviewKeyDown);
var button = sender as Button;
if (button != null)
button.Click += new RoutedEventHandler(button_Click);
}
}
private static void button_Click(object sender, RoutedEventArgs e)
{
MainWindow.Close();
}
private static void MainWindow_PreviewKeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Escape)
MainWindow.Close();
}
}
And in MainWindow use this Behavior like as:
<Window x:Class="MyProjectNamespace.MainWindow"
xmlns:local="clr-namespace:MyProjectNamespace">
<Button Name="CloseButton"
local:ButtonBehavior.IsClose="True" ... />

How can I create a click event on a custom user control?

I've created a custom user control. Is it possible for me to add a click event so that when someone clicks anywhere in the area of the control, a click event is fired?
The user control is defined as:
XAML:
<Grid x:Name="LayoutRoot" Background="{StaticResource PhoneChromeBrush}">
<StackPanel Orientation="Vertical">
<Image Source="{Binding TabItemImage}" HorizontalAlignment="Center" Stretch="None" VerticalAlignment="Top" />
<TextBlock Text="{Binding TabItemText}" FontSize="15" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
</StackPanel>
</Grid>
C#:
public partial class TabItem : UserControl
{
public static readonly DependencyProperty ImageProperty = DependencyProperty.Register("TabItemImage", typeof(string), typeof(TabItem), null);
public static readonly DependencyProperty TextProperty = DependencyProperty.Register("TabItemText", typeof(string), typeof(TabItem), null);
public string TabItemImage
{
get { return (string)GetValue(ImageProperty); }
set { SetValue(ImageProperty, value); }
}
public string TabItemText
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public TabItem()
{
InitializeComponent();
this.DataContext = this;
}
}
With the usage simply:
<tabs:TabItem TabItemText="OVERVIEW" TabItemImage="/Resources/Images/overview.png" />
Ideally I'd be able to modify the user control so that I could specify the click event, e.g.
<tabs:TabItem
TabItemText="OVERVIEW"
TabItemImage="/Resources/Images/options_64.png"
Click="TabItem_Clicked"/> <!-- when someone clicks the control, this fires -->
Is this possible? If so, what do I need to do to create a click event on a custom user control?

You need to add custom RoutedEvent to your TabItem UserControl, Below is code to add a Custom RoutedEvent:
public static readonly RoutedEvent ClickEvent = EventManager.RegisterRoutedEvent(
"Click", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(TabItem));
public event RoutedEventHandler Click
{
add { AddHandler(ClickEvent, value); }
remove { RemoveHandler(ClickEvent, value); }
}
void RaiseClickEvent()
{
RoutedEventArgs newEventArgs = new RoutedEventArgs(TabItem.ClickEvent);
RaiseEvent(newEventArgs);
}
void OnClick()
{
RaiseClickEvent();
}
And then in your UserControl InitializeMethod wire up PreviewMouseLeftButtonUp event to fire your Custom RoutedEvent:
PreviewMouseLeftButtonUp += (sender, args) => OnClick();
There is a pretty good How-to on MSDN discussing this, you might want to read that.

This answer by Suresh has a good point and that would be a great way to do it. However, If you don't have more than one click event for this UserControl, you can you just use the any of the number of mouseclick events that come with defining a custom UserControl.
I didn't know you could set the datacontext to its self... That is interesting.
XAML:
<UserControl x:Class="StackTest.TestControl"
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"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
MouseLeftButtonUp="TestControl_OnMouseLeftButtonUp"
MouseDoubleClick="TestControl_OnMouseDoubleClick"
MouseLeftButtonDown="TestControl_OnMouseLeftButtonDown">
<Grid x:Name="LayoutRoot" Background="{StaticResource PhoneChromeBrush}">
<StackPanel Orientation="Vertical">
<Image Source="{Binding TabItemImage}" HorizontalAlignment="Center" Stretch="None" VerticalAlignment="Top" />
<TextBlock Text="{Binding TabItemText}" FontSize="15" HorizontalAlignment="Center" VerticalAlignment="Bottom" />
</StackPanel>
</Grid>
</UserControl>
CS:
public partial class TestControl : UserControl
{
public static readonly DependencyProperty ImageProperty = DependencyProperty.Register("TabItemImage" , typeof(string) , typeof(TabItem) , null);
public static readonly DependencyProperty TextProperty = DependencyProperty.Register("TabItemText" , typeof(string) , typeof(TabItem) , null);
public string TabItemImage
{
get { return (string)GetValue(ImageProperty); }
set { SetValue(ImageProperty , value); }
}
public string TabItemText
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty , value); }
}
public TestControl()
{
InitializeComponent();
this.DataContext = this;
}
// or
private void TestControl_OnMouseDoubleClick(object sender, MouseButtonEventArgs e)
{
// Add logic...
}
// or
private void TestControl_OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
// Add logic...
}
// or
private void TestControl_OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
// Add logic...
}
}

This answer by Suresh requires the following namespace declarations:
using System;
using System.Windows;
using System.Windows.Controls;
namespace YourNameSpace
{
partial class OPButton
{
/// <summary>
/// Create a custom routed event by first registering a RoutedEventID
/// This event uses the bubbling routing strategy
/// see the web page https://msdn.microsoft.com/EN-US/library/vstudio/ms598898(v=vs.90).aspx
/// </summary>
public static readonly RoutedEvent ClickEvent = EventManager.RegisterRoutedEvent("Click", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(OPButton));
/// <summary>
/// Provide CLR accessors for the event Click OPButton
/// Adds a routed event handler for a specified routed event Click, adding the handler to the handler collection on the current element.
/// </summary>
public event RoutedEventHandler Click
{
add {AddHandler(ClickEvent, value); }
remove { RemoveHandler(ClickEvent, value); }
}
/// <summary>
/// This method raises the Click event
/// </summary>
private void RaiseClickEvent()
{
RoutedEventArgs newEventArgs = new RoutedEventArgs(OPButton.ClickEvent);
RaiseEvent(newEventArgs);
}
/// <summary>
/// For isPressed purposes we raise the event when the OPButton is clicked
/// </summary>
private void OnClick()
{
RaiseClickEvent();
}
}
}
And the following References:
Windows;
PresentationCore;
WindowsBase;

Silverlight custom EventTrigger

I am trying to create a custom event to trigger an animation in Silverlight. Although the event is getting triggered, the animation is not working. The following is the relevant code:
namespace SilverlightApplication1
{
public partial class MainPage : UserControl
{
public MainPage()
{
MyEvent += new ChangedEventHandler(UserControl_MyEventHandler);
/* Other stuff */
}
private void UserControl_MyEventHandler(object sender, RoutedEventArgs e)
{
MessageBox.Show("MyEventHandler has been called");
}
public delegate void ChangedEventHandler(object sender, RoutedEventArgs e);
private event ChangedEventHandler MyEvent;
private void UserControl_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if (MyEvent != null)
MyEvent(this, e);
}
}
}
The XAML code is as follows:
<UserControl
...
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity" mc:Ignorable="d"
x:Class="SilverlightApplication1.MainPage" MouseLeftButtonDown="UserControl_MouseLeftButtonDown">
<Grid x:Name="LayoutRoot" Background="White">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MyEvent">
<ei:GoToStateAction StateName="Highlighted"/>
</i:EventTrigger>
</i:Interaction.Triggers>
...
</Grid>
</UserControl>
Current, the message box containing "MouseLeftButtonDown" is getting displayed but the animation is not getting called. The animation did get called when the EventTrigger EventName was MouseLeftButtonDown instead of MyEvent. Please help me out. Thanks.

You can set SourceName in EventTrigger if you want to trigger on event of some control.
I guess, in your case in code behind:
VisualStateManager.GoToState(this [or some other object with Highlighted state], "Highlighted", false);