WPF InkCanvas - can't change color

Question

This is absolutely ridiculous! I'm trying to change the color of inkCanvas through code but it doesn't work. I saw a lot of tutorials about that and they don't work for me. Even though they're straightforward. I'm new to WPF but still - this should be a no-brainer.

*Note: I can set the color through XAML but that's a one-time operation and not what I want.

My code:

using System.Windows;
using System.Windows.Controls;
using System.Windows.Ink;
using System.Windows.Media;

namespace WpfApplication1
{
    public partial class MainWindow : Window
    {
        InkCanvas inkCanvas = new InkCanvas();

        public MainWindow()
        {
            InitializeComponent();
            this.Loaded += new RoutedEventHandler(SetColor);
        }

        // doesn't work
        private void SetColor(object sender, RoutedEventArgs e)
        {
            inkCanvas.DefaultDrawingAttributes.Color = Colors.Red;
        }
         // doesn't work either
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            inkAttributes.Color = Colors.Blue;
        }
    }
}

Edit: My XAML was:

<Window...
< InkCanvas Name="inkCanvas" /> ....

Have you tried binding the colour to a property in XAML? – ChrisF Jan 07 '16 at 14:25 — ChrisF, Jan 07 '16 at 14:25

score 2 · Accepted Answer · answered Jan 07 '16 at 14:37

2

In your code sample, you define inkCanvas in the window's code-behind, but don't add it to the window's visual controls.

If you either specify the canvas using XAML:

<Window x:Class="..."
        ...>
    <InkCanvas x:Name="inkCanvas"/>
</Window>

or define it in C# and add it to the window:

InkCanvas inkCanvas = new InkCanvas();

public MainWindow()
{
    InitializeComponent();
    this.Loaded += (sender, args) =>
    {
        this.AddChild(inkCanvas);
    };
}

Then the line inkCanvas.DefaultDrawingAttributes.Color = Colors.Red; shold actually work.

answered Jan 07 '16 at 14:37

andreask

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That's it! In XAML I used the "Name" attribute instead of "x:Name". I didn't even thought about searching for the problem there. It appears the later makes the connection with code-behind. Thank you very much! – Bruno Jan 07 '16 at 14:56
Actually, the problem was that I had defined `InkCanvas inkCanvas = new InkCanvas();` in code-behind even though I already had an element with such name. Removing the line fixes this ambiguity(which the compiler does not mark as problematic). – Bruno Jan 07 '16 at 15:08

WPF InkCanvas - can't change color

1 Answers1