Can TaskbarItemInfo ThumbnailClipMargin support negative numbers?

Question

For example:

    <Window.TaskbarItemInfo>
        <TaskbarItemInfo ThumbnailClipMargin="-100,-100,100,100"></TaskbarItemInfo>
    </Window.TaskbarItemInfo>

But,it doesn't work.

I use another method:

        public MainWindow_Loaded()
        { 
            this.LayoutUpdated += new EventHandler(LayoutUpdated);
            this.UpdateTaskbarPreview();
        }
        void LayoutUpdated(object sender, EventArgs e)
        {
            this.UpdateTaskbarPreview();
        }
        void UpdateTaskbarPreview()
        {
            RECT rect = new RECT(-100,-100,100,100);
            TaskbarManager.Instance.SetThumbnailClip(new System.Windows.Interop.WindowInteropHelper(this).Handle, rect);

        }

But,it doesn't work too.

If all the numbers are positive,It works:

        public MainWindow_Loaded()
        { 
            this.LayoutUpdated += new EventHandler(LayoutUpdated);
            this.UpdateTaskbarPreview();
        }
        void LayoutUpdated(object sender, EventArgs e)
        {
            this.UpdateTaskbarPreview();
        }
        void UpdateTaskbarPreview()
        {
            RECT rect = new RECT(100,100,100,100);
            TaskbarManager.Instance.SetThumbnailClip(new System.Windows.Interop.WindowInteropHelper(this).Handle, rect);

        }

Answer 1

Nobody knows?

Answer 2

Why do you need negative margin? Do you need to see desktop on the thumb? 

Answer 3

I don't need to see desktop on the thumb.

I need to see a whole child element,such as:

<Window ……>

    <Grid Width="600" Height="600">
        <Button Name="b1" Width="200" Height="200" 
                 FontSize="80" VerticalAlignment="Top" 
                 HorizontalAlignment="Left" Content="Hello">
            <Button.RenderTransform>
                <TransformGroup>
                    <TranslateTransform X="-100" Y="100"></TranslateTransform>
                </TransformGroup>
            </Button.RenderTransform>
        </Button>
    </Grid>

</Window>

I need to see the whole b1 on the thumb. Can I?

Answer 4

Why do you need negative margin? Do you need to see desktop on the thumb? 

I don't need to see desktop on the thumb.

I need to see a whole child element,such as:

<Window ……>

    <Grid Width="600" Height="600">
        <Button Name="b1" Width="200" Height="200" 
                 FontSize="80" VerticalAlignment="Top" 
                 HorizontalAlignment="Left" Content="Hello">
            <Button.RenderTransform>
                <TransformGroup>
                    <TranslateTransform X="-100" Y="100"></TranslateTransform>
                </TransformGroup>
            </Button.RenderTransform>
        </Button>
    </Grid>

</Window>

I need to see the whole b1 on the thumb. Can I?

Answer 5

Hi yqhszn20j,

"ThumbnailClipMargin" property does not support negative value, as far as I know, any negative, NaN or infinity value will be treated as zero value.

Best regards,

---

Sheldon _Xiao[MSFT]
MSDN Community Support | Feedback to us
Microsoft
Please remember to mark the replies as answers if they help and unmark them if they provide no help.

Answer 6

http://msdn.microsoft.com/en-us/library/system.windows.shell.taskbariteminfo.thumbnailclipmargin.aspx

On window client area starts from  top left  ( cooordinates 0 0). Margins are offsets of windows client area(left,top,right,bottom). negative values are not on the visible parts of the window. If you translate button to the negative side of the windows it will be clipped eventually. 

Regards..