Why doesn't TextBlock bind?

Question

When I run this simple wpf app, I get a blank window. Any ideas what I'm doing wrong?

//MainWindow.xaml.cs
public string SimpleText {get;set;}
public MainWindow()
{
  InitializeComponent();
  SimpleText = "this is a test";
}

//MainWindow.xaml
<StackPanel>
  <TextBlock Text="{Binding SimpleText}" Width="200"/>
</StackPanel>

score 2 · Answer 1 · answered Feb 14 '14 at 18:07

2

DataContext is a way to go but you can also use RelativeSource markup extension to get window's property:

<TextBlock Text="{Binding SimpleText, RelativeSource={RelativeSource
                          Mode=FindAncestor, AncestorType=Window}}" Width="200"/>

answered Feb 14 '14 at 18:07

Rohit Vats

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Yeah I just provided with another way to achieve that without setting DataContext. – Rohit Vats Feb 14 '14 at 18:09

Anatoliy Nikolaev · Accepted Answer · 2014-02-14T18:27:39.217

You must set the DataContext:

public MainWindow()
{
    InitializeComponent();
    SimpleText = "this is a test";
    this.DataContext = this;
}

As an alternative, you can set DataContext on the side XAML like this:

XAML

<Window x:Class="TextBlockDontBind.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:this="clr-namespace:TextBlockDontBind"
    Title="MainWindow" Height="350" Width="525">

    <Window.DataContext>
        <this:TestData />
    </Window.DataContext>

    <StackPanel>
        <TextBlock Text="{Binding SimpleText}" Width="200"/>
    </StackPanel>
</Window>

Code-behind

public class TestData
{
    private string _simpleText = "this is a test";

    public string SimpleText
    {
        get
        {
            return _simpleText;
        }

        set
        {
            _simpleText = value;
        }
    }
}

But in this case to update a property, for a Class must implement the INotifyPropertyChanged interface.

Thanks! You can also set the DataContext before the text assignment. — 4thSpace, Feb 14 '14 at 18:06
Expanding on this example, do you have any idea why this scenario displays a blank window: http://stackoverflow.com/questions/21767121/how-to-bind-to-collection-2-deep? DataContext is now set but still nothing. — 4thSpace, Feb 14 '14 at 18:18
@4thSpace: Please see my edit where I described an alternative for setting `DataContext`. Okay, I see this question. — Anatoliy Nikolaev, Feb 14 '14 at 18:23

Why doesn't TextBlock bind?

2 Answers2