WPF - Two way binding use a user control...binding to object, not an element!
- by Scott
I created an object with a simple property with a default value. I then created a user control that has a text box in it. I set the datacontext of the user control to the object.
The text box correctly shows the properties default value but I can't seem to update the property value when the user changes the text box value. I created a simple project to illustrate my code.
Thanks for the help!!
public partial class UserControl1 : UserControl
{
public UserControl1()
{
InitializeComponent();
}
private string _titleValue;
public string TitleValue
{
get
{
return _titleValue;
}
set
{
_titleValue = value;
textBox1.Text = _titleValue;
}
}
public static readonly DependencyProperty TitleValueProperty = DependencyProperty.Register(
"TitleValue", typeof(string), typeof(UserControl1), new FrameworkPropertyMetadata(new PropertyChangedCallback(titleUpdated))
);
//Don't think I should need to do this!!!
private static void titleUpdated(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((UserControl1)d).TitleValue = (string)e.NewValue;
}
}
<UserControl x:Class="WpfApplication1.UserControl1"
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"
d:DesignHeight="300" d:DesignWidth="300">
<Grid>
<TextBox Height="23" HorizontalAlignment="Left" Margin="94,97,0,0" Name="textBox1" VerticalAlignment="Top" Width="120"
Text="{Binding Path=TitleValue, Mode=TwoWay}"/>
</Grid>
</UserControl>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
var dummy = new DummyObject("This is my title.");
userControl11.DataContext = dummy;
}
private void button1_Click(object sender, RoutedEventArgs e)
{
MessageBox.Show("The value is: " + ((DummyObject)userControl11.DataContext).Title);
}
}
<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" xmlns:my="clr-namespace:WpfApplication1">
<Grid>
<my:UserControl1 HorizontalAlignment="Left" Margin="95,44,0,0" x:Name="userControl11" VerticalAlignment="Top" Height="191" Width="293"
TitleValue="{Binding Path=Title, Mode=TwoWay}"/>
<Button Content="Check Value" Height="23" HorizontalAlignment="Left" Margin="20,12,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" />
</Grid>
</Window>
