CODEWITHSUNDEEP
c#wpfcanvasoverriding
Kishore Kumar
Kishore Kumar

Reputation: 12884

How to Override Children.Add method of Canvas class in WPF

I already have a Custom Canvas class in which i have override the 'OnMoseDown' method. But now i also want to override 'Children.Add' method. But i didnt find any solution.

I want to get Child.ActualWidth when a child gets added to canvas.

Thanks.

Upvotes: 0

Views: 1736

Answers (2)

Kishore Kumar
Kishore Kumar

Reputation: 12884

I just found my answer by myself. Hope this may help someone on some day.

Just added a Add method in my Custom class

public void Add(UserControl element)
{
    bool alreadyExist = false;
    element.Uid = element.Name;
    foreach (UIElement child in this.Children)
    {
        if (child.Uid == element.Uid)
        {
            alreadyExist = true;
            this.BringToFront(child);
        }
    }
    if (!alreadyExist)
    {
        this.Children.Add(element);
        this.UpdateLayout();
        double top = (this.ActualHeight - element.ActualHeight) / 2;
        double left = (this.ActualWidth - element.ActualWidth) / 2;
        Canvas.SetLeft(element, left);
        Canvas.SetTop(element, top);
    }
}

Upvotes: 1

Reed Copsey
Reed Copsey

Reputation: 564851

This will likely not work correctly. A child will get added before it's ActualWidth is set, as that property gets set during the layout phase.

Depending on your goals here, you may want to consider overriding MeasureOverride and ArrangeOverride instead, and making a custom layout panel instead of subclassing Canvas.

Upvotes: 0

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