Multiple DrawingViews?

[maslewandowski]

I would love to present a mockup of .NET Maui Apps to my CEO, but as I initalized many DrawingViews in xaml, the drawed lines are shared between those multiple drawingviews. I guess they use the same object for the drawed lines, but how can i use more than one drawingview?

[VladislavAntonyuk]

please provide a link to the repo to reproduce the issue.
I am not able to reproduce it:

            <mct:DrawingView x:Name="DrawingViewControl"
                             Margin="0,0,0,10"
                             Grid.Row="8" Grid.Column="0"
                             LineColor="Green"
                             LineWidth="5"
                             Lines="{Binding Lines, Mode=TwoWay}"
                             DrawingLineCompleted="OnDrawingLineCompleted"
                             DrawingLineCompletedCommand="{Binding DrawingLineCompletedCommand}"
                             ShouldClearOnFinish="{Binding Source={x:Reference ClearOnFinish}, Path=IsToggled}"
                             IsMultiLineModeEnabled="{Binding Source={x:Reference MultiLineMode}, Path=IsToggled}">
                <mct:DrawingView.Background>
                    <LinearGradientBrush StartPoint="0,0"
                                         EndPoint="0,1">
                        <GradientStop Color="Blue"
                                      Offset="0"/>
                        <GradientStop Color="Yellow"
                                      Offset="1"/>
                    </LinearGradientBrush>
                </mct:DrawingView.Background>
            </mct:DrawingView>
            
<mct:DrawingView x:Name="DrawingViewControl2"
                             Margin="0,0,0,10"
                             Grid.Row="8" Grid.Column="1"
                             LineColor="Green"
                             LineWidth="5"
                             DrawingLineCompleted="OnDrawingLineCompleted"
                             DrawingLineCompletedCommand="{Binding DrawingLineCompletedCommand}"
                             ShouldClearOnFinish="{Binding Source={x:Reference ClearOnFinish}, Path=IsToggled}"
                             IsMultiLineModeEnabled="{Binding Source={x:Reference MultiLineMode}, Path=IsToggled}">
                <mct:DrawingView.Background>
                    <LinearGradientBrush StartPoint="0,0"
                                         EndPoint="0,1">
                        <GradientStop Color="Blue"
                                      Offset="0"/>
                        <GradientStop Color="Yellow"
                                      Offset="1"/>
                    </LinearGradientBrush>
                </mct:DrawingView.Background>
            </mct:DrawingView>

[maslewandowski]

https://github.com/maslewandowski/drawingviewproblem

Hope this one works

thanks

[Ghostbird]

Yeah, I'm having this issue too. It seems there's one static storage for drawn lines. If I go to a new page, and put a drawingview there, it will show the drawing from a completely different page. As soon as you clear the lines, all drawing views in the app are cleared. As soon as you complete drawing a line, it's shown on all drawing views in the app.

[Ghostbird]

Found it! That there's a default one-time created ObservableCollection<IDrawingLine>().

The workaround then is simple. Set the Lines property of the DrawingView to a new ObservableCollection<IDrawingLine>().

[Ghostbird]

The fix is to change the line I link above to:

nameof(Lines), typeof(ObservableCollection<IDrawingLine>), typeof(DrawingView), defaultValueCreator: (_) => new ObservableCollection<IDrawingLine>(), defaultBindingMode: BindingMode.TwoWay);

I'll make a PR after lunch.

[Ghostbird]

PR#862

[Ghostbird]

@maslewandowski PR is merged. Could you mark this question as answered?

[CliffAgius]

Closed as answered