Adding a click-event to all textboxes in wpf - wpf

Question

in my applications all inputs in textboxes have to be done by a inputbox i wrote myself. so whenever a textbox is klicked, the inputbox pops up. it looks like this:
the textbox in xaml:
<TextBox Text="{Binding Level}" Grid.Row="1" Grid.Column="2" Margin="2">
<TextBox.InputBindings>
<MouseBinding Command="{Binding EnterLevel}" MouseAction="LeftClick" />
</TextBox.InputBindings>
</TextBox>
the command in the VM:
private void ExecuteEnterLevel()
{
var dialog = new BFH.InputBox.InputBox("Level", 1, 1, 4);
dialog.ShowDialog();
Level = Convert.ToInt16(dialog.Input);
}
so the result of the inputbox becomes the text of the inputbox. this works fine.
now my question is: can i do that for all of my textboxes that need that functionality without coding an event for every single textbox? i would like to have "myTextbox" which does it automatically.
what i tried so far:
my textbox:
class MyTextbox : TextBox
{
public MyTextbox()
{
this.MouseDown += MyTextbox_MouseDown;
}
private void MyTextbox_MouseDown(object sender, MouseButtonEventArgs mouseButtonEventArgs)
{
TextBox tb = (TextBox)sender;
var dialog = new BFH.InputBox.InputBox("titel", "input");
dialog.ShowDialog();
tb.Text = dialog.Input;
}
}
and in xaml:
<libraries:MyTextbox/>
but MyTextbox_MouseDown is never executet. i put MessageBox.Show("test") in it without any results. i am doing something wrong i guess.

Answer 1

Since it is not possible to define InputBindings in styles, at least in a straight forward way. I offer to solve the issue by using AttachedProperties
lets start by defining a class for the attached property
namespace CSharpWPF
{
class EventHelper
{
public static ICommand GetLeftClick(DependencyObject obj)
{
return (ICommand)obj.GetValue(LeftClickProperty);
}
public static void SetLeftClick(DependencyObject obj, ICommand value)
{
obj.SetValue(LeftClickProperty, value);
}
// Using a DependencyProperty as the backing store for LeftClick. This enables animation, styling, binding, etc...
public static readonly DependencyProperty LeftClickProperty =
DependencyProperty.RegisterAttached("LeftClick", typeof(ICommand), typeof(EventHelper), new PropertyMetadata(null, OnLeftClickChanged));
private static void OnLeftClickChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
FrameworkElement elem = d as FrameworkElement;
ICommand command = e.NewValue as ICommand;
if (command != null)
elem.InputBindings.Add(new MouseBinding(command, new MouseGesture(MouseAction.LeftClick)));
}
}
}
this is basically translation of mouse binding in your code done on property changed.
usage
<TextBox l:EventHelper.LeftClick="{Binding MyCommand}" />
if you wish to apply to all TextBoxes then wrap the same in a generic style targeted to TextBox
<Style TargetType="TextBox">
<Setter Property="l:EventHelper.LeftClick"
Value="{Binding MyCommand}" />
</Style>
l: in the above refers to the name space of the above declared class eg xmlns:l="clr-namespace:CSharpWPF"
a full example
<StackPanel xmlns:l="clr-namespace:CSharpWPF">
<StackPanel.Resources>
<Style TargetType="TextBox">
<Setter Property="l:EventHelper.LeftClick"
Value="{Binding MyCommand}" />
</Style>
</StackPanel.Resources>
<TextBox />
<TextBox />
<TextBox />
<TextBox />
</StackPanel>
Attaching input box behavior
class
class InputHelper
{
public static bool GetIsInputBoxEnabled(DependencyObject obj)
{
return (bool)obj.GetValue(IsInputBoxEnabledProperty);
}
public static void SetIsInputBoxEnabled(DependencyObject obj, bool value)
{
obj.SetValue(IsInputBoxEnabledProperty, value);
}
// Using a DependencyProperty as the backing store for IsInputBoxEnabled. This enables animation, styling, binding, etc...
public static readonly DependencyProperty IsInputBoxEnabledProperty =
DependencyProperty.RegisterAttached("IsInputBoxEnabled", typeof(bool), typeof(InputHelper), new PropertyMetadata(false, OnIsInputBoxEnabled));
private static void OnIsInputBoxEnabled(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
TextBox tb = d as TextBox;
if ((bool)e.NewValue)
tb.PreviewMouseDown += elem_MouseDown;
else
tb.PreviewMouseDown -= elem_MouseDown;
}
static void elem_MouseDown(object sender, MouseButtonEventArgs e)
{
TextBox tb = sender as TextBox;
var dialog = new BFH.InputBox.InputBox(tb.GetValue(InputBoxTitleProperty), tb.GetValue(InputProperty));
dialog.ShowDialog();
tb.Text = dialog.Input;
}
public static string GetInputBoxTitle(DependencyObject obj)
{
return (string)obj.GetValue(InputBoxTitleProperty);
}
public static void SetInputBoxTitle(DependencyObject obj, string value)
{
obj.SetValue(InputBoxTitleProperty, value);
}
// Using a DependencyProperty as the backing store for InputBoxTitle. This enables animation, styling, binding, etc...
public static readonly DependencyProperty InputBoxTitleProperty =
DependencyProperty.RegisterAttached("InputBoxTitle", typeof(string), typeof(InputHelper), new PropertyMetadata(null));
public static string GetInput(DependencyObject obj)
{
return (string)obj.GetValue(InputProperty);
}
public static void SetInput(DependencyObject obj, string value)
{
obj.SetValue(InputProperty, value);
}
// Using a DependencyProperty as the backing store for Input. This enables animation, styling, binding, etc...
public static readonly DependencyProperty InputProperty =
DependencyProperty.RegisterAttached("Input", typeof(string), typeof(InputHelper), new PropertyMetadata(null));
}
usage
<TextBox l:InputHelper.IsInputBoxEnabled="true"
l:InputHelper.InputBoxTitle="Title"
l:InputHelper.Input="Input" />
or via styles
<Style TargetType="TextBox">
<Setter Property="l:InputHelper.IsInputBoxEnabled"
Value="true" />
<Setter Property="l:InputHelper.Title"
Value="true" />
<Setter Property="l:InputHelper.Input"
Value="Input" />
</Style>
using attached properties will enable you to attach this behavior to existing classes instead of inheriting from them.
if you are inheriting the text box class you can add two properties to the same
eg
class MyTextbox : TextBox
{
public MyTextbox()
{
this.PreviewMouseDown += MyTextbox_MouseDown;
}
private void MyTextbox_MouseDown(object sender, MouseButtonEventArgs mouseButtonEventArgs)
{
TextBox tb = (TextBox)sender;
var dialog = new BFH.InputBox.InputBox(InputBoxTitle, Input);
dialog.ShowDialog();
tb.Text = dialog.Input;
}
public string InputBoxTitle { get; set; }
public string Input { get; set; }
}
usage
<libraries:MyTextbox InputBoxTitle="Title"
Input="Input" />