"C#/WPF" uses thumb to make a draggable UI control

Original: "C#/WPF" uses thumb to make a draggable UI control

Requirements: Simple draggable pictures

Using the System.Windows.Controls.Primitives.Thumb class

Front desk:

<Canvas x:name="G">    <Thumb canvas.left="Ten" canvas.top= " canvas.zindex" ="dragdelta" = "Thumb_dragdelta">          <thumb.template>            <ControlTemplate>                <image Width=" max" Height= "All" Source="Your picture path" />            </ControlTemplate>        </thumb.template>    </Thumb></Canvas>

Background:

private void Thumb_dragdelta (object sender, System. Windows. Controls. Primitives. DragDeltaEventArgse) {UIElement thumb = E. SourceAs UIElement;Prevents the thumb control from being dragged out of the container. if (NTop <=0)//NTop =0;if (NTop >= (g. Height-Mythumb. Height))//NTop = g. Height-Mythumb. Height;if (Nleft <=0)//Nleft =0;if (Nleft >= (g. Width-Mythumb. Width))//Nleft = g. Width-Mythumb. Width;Canvas. Settop(Mythumb, NTop);Canvas. Setleft(Mythumb, Nleft);Tt. Text="Top:"+ NTop. ToString() +"\nleft:"+ Nleft. ToString();Canvas. Setleft(Thumb, Canvas. GetLeft(thumb) + E. Horizontalchange);Canvas. Settop(Thumb, Canvas. GetTop(thumb) + E. Verticalchange);}

Pit point:

• The thumb must be a subclass of a canvas, because it relies on the canvas to locate it.
• The thumb must negotiate canvas.left and canvas.top, because it relies on the vanvas to locate it, otherwise it cannot be dragged!

Important References:

• https://wpf.2000things.com/2012/12/19/715-using-the-thumb-control-to-drag-objects-on-a-canvas/
• Https://msdn.microsoft.com/en-us/library/system.windows.controls.primitives.thumb (v=vs.110). aspx

"C#/WPF" uses thumb to make a draggable UI control