CODEWITHSUNDEEP
c#wpf
jjw
jjw

Reputation: 294

How do access the property of the child control?

My English skill is poor because I'm not a native English speaker.

I have created two custom control. First control has a DP named CaretIndexFromLine and the control name is TextArea. The following is the summarized cs code of the first control.

public class TextArea : TextBox
{
    public int CaretIndexFromLine
    {
        get { return (int)GetValue(CaretIndexFromLineProperty ); }
        set { SetValue(CaretIndexFromLineProperty , value); }
    }

    public static readonly DependencyProperty CaretIndexFromLineProperty =
        DependencyProperty.Register("CaretIndexFromLine", typeof(int), typeof(TextArea), new P 
        ropertyMetadata(0));
   ...
}

The second control named Editor has child control TextArea.

The following is the summarized XAML code of the second control.

<Editor> <TextArea x:Name="PART_TextArea"/> </Editor>

And the following is summarized cs code of the second control.

public class Editor : Control
{
    public TextArea TextArea { get; private set; }

    public override void OnApplyTemplate()
    {
        base.OnApplyTemplate();

        this.TextArea = (TextArea)Template.FindName("PART_TextArea", this);
    }

    ...
}

And I was going to use the above control in the MainWindow.

<MainWindow> <Editor/> </MainWindow>

There is a problem here. I want to access the property (CaretIndex) of the TextArea in the XAML code. I tried like this but It was not operated.

<MainWindow>
  <StackPanel>
    <Editor x:Name="editor"/>
    <TextBlock Text="{Binding ElementName=editor.TextArea, Path=CaretIndexFromLine}/>
  </StackPanel>
</MainWindow>

What should I do to achieve the above goal?

Thank you for reading this and please teach me the solution.

Upvotes: 1

Views: 67

Answers (1)

mm8
mm8

Reputation: 169150

Your Editor control has an TextArea property so just set the ElementName to "editor" and the Path to TextArea.CaretIndexFromLine:

<TextBlock Text="{Binding ElementName=editor, Path=TextArea.CaretIndexFromLine}/>

TextArea should be a read-only dependency property though in order for a notification to be raised when it's set in the OnApplyTemplate() method.

Upvotes: 2

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