How do I add elements to a WPF canvas from a separate class file?

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I am trying to write a function in C# to draw an Ellipse to a canvas (canvas1) that I have created in a separate Window1.xaml file. My problem arises when I try to add the Ellipse(node) to the canvas via:

canvas1.Children.Add(node);

canvas1 does not exist in the current context. I need to know how to access canvas1 in this context.

Posted 17-Apr-10 6:57am

ineale

Updated 17-Apr-10 7:21am

#realJSOP

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3 solutions

Solution 1

I would create the Canvas object in question as a static (and globally accessible) object, and just use the static instance wherever it's needed.

Posted 17-Apr-10 7:22am

#realJSOP

Solution 3

I'm not sure if this is the proper method of asking questions about answers, but Thank you for your responses.

Rajitha, your first solution has fixed the related errors thank you!

John, how should I go about making the canvas static and global in XAML?

Posted 17-Apr-10 10:44am

ineale

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Rajitha Wimalasooriya · Accepted Answer · 2010-04-17T08:54:00

If your function is being called from the code behind of Window1 you can pass the canvas as a parameter to your function.

C#

public void AddEllipse(Canvas canvas)
{
    ...
    ...

    canvas.Children.Add(node);
}

If your function is being called from some other code you can expose the canvas as a public property of Window1.

C#

public Canvas Canvas1
{
    get
    {
        return canvas1;
    }
}

Then through any instance of Window1 you can access the Canvas1 property and pass it to your function.