CODEWITHSUNDEEP
c#.netwpf
Nathan Abramov
Nathan Abramov

Reputation: 115

Cannot change object property from other window

I have the main window, and another window. in the 2nd window i've created new canvas, and i want to change its properties from the main window, i've failed with this try:

this is the 2nd window's class: 

public partial class window2 : Window
{
    public Canvas painting = new Canvas();

    public window2()
    {
    }
}

and here i try to change its property from the main window:

window2 paint = new window2();

private void button1_Click(object sender, RoutedEventArgs e)
{
    paint.painting.Background = Brushes.Black;
}

when i click the button it does nothing.

Edit:

i think it would be better if i'll use the Application.current.properties and store the canvas object, but i don't know how to use it, i tried this:

Application.Current.Properties["p1"] = painting;

now how can i set properties from the main window with using the "p1" variable i've just created? i tried p1.background but i cant use p1 as variable, so how do i do it?

Upvotes: 1

Views: 253

Answers (2)

Sumi
Sumi

Reputation: 127

Your window2 constructor should contain this: 

this.AddChild(painting);

Whenever you create a new control (like Canvas) you should set its parent container.

This is my code from window2:

public Canvas painting = new Canvas();

public window2()
{
    this.AddChild(painting);
}

And mainwindow:

private void button1_Click(object sender, RoutedEventArgs e)
{
    window2 w = new window2();
    w.Show();
    w.painting.Background = Brushes.Black;
}

What I believe you are saying is that you have an undetermined number of canvases and you want to access them all. I suggest you keeping them in a List of canvases or in a HashTable (you need to use System.Collections namespace). Also don't forget to set the parent container.

Upvotes: 1

Kent Boogaart
Kent Boogaart

Reputation: 178660

A Canvas is a little odd as far as WPF controls go. It likely has a zero size, so you're not seeing the change. Try hard-coding a size to check whether the code is working. In the window2 constructor do this:

painting.Width = 100;
painting.Height = 100;

Upvotes: 0

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