Question

I have next problem: i have a View:

<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>
        <TextBlock>
            test
            <TextBlock Text="{Binding TestingTest}"></TextBlock>
            test
        </TextBlock>
    </Grid>
</UserControl>

with code-behind:

    public partial class UserControl1 : UserControl
{
    public UserControl1()
    {
        InitializeComponent();
    }

    public string TestingTest
    {
        get { return (string)GetValue(TestingTestProperty); }
        set { SetValue(TestingTestProperty, value); }
    }

    public static readonly DependencyProperty TestingTestProperty =
        DependencyProperty.Register("TestingTest", typeof(string), typeof(UserControl1), new UIPropertyMetadata("testing test"));

}

and i try to use this view in my view with ViewModel:

<Window x:Class="WpfApplication1.MainWindow" Name="wnd" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:WpfApplication1="clr-namespace:WpfApplication1" Title="MainWindow" Height="350" Width="525">
<Grid>
    <WpfApplication1:UserControl1 TestingTest="{Binding ElementName=wnd, Path=Title}"></WpfApplication1:UserControl1>
</Grid>

ViewModel:

    public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = this;
    }

    public string GoGoGo
    {
        get
        {
            return "Test message";
        }
    }
}

but every time i got next message in Output window and dont see test message:

*System.Windows.Data Error: 40 : BindingExpression path error: ‘TestingTest’ property not found on ‘object’ ”UserControl1′ (Name=’my’)’. BindingExpression:Path=TestingText; DataItem=’UserControl1′ (Name=’my’); target element is ‘TextBlock’ (Name=”); target property is ‘Text’ (type ‘String’)
*

What do i wrong?

Answer 1

It’s a typo.

On your UserControl you have the property TestingTest and on the WPF you have TestingText (‘s’ and ‘x’)