c# - Why doesnt assigning a new value to a controls location property change its location at runtime? -

whenever need move control's location on form @ run-time, have assign new values top , left properties!
why doesn't location property trick?
example should able :

private void btn_mousemove(object sender, mouseeventargs e)         {             if (e.button == mousebuttons.left)             {                 ((button)sender).location = e.location;             }          } 

but doesn't work , instead have way:

private void btn_mousemove(object sender, mouseeventargs e)         {             if (e.button == mousebuttons.left)             {                 ((button)sender).left = e.x + ((button)sender).left;                 ((button)sender).top = e.y + ((button)sender).top;             }          } 

those 2 code snippets not equivalent.

the mouseeventargs reports coordinates relative to control you've attached mousemove event to, in case button.

in first example, e.location 0,0 when mouse located @ top-left corner of button. button's location set 0,0, since its location relative form it's on, button jumps top-left corner of form.

in second example, you're setting location correctly adding e.x , e.y existing left , top properties of button, respectively.

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to "fix" first example, you'd have modify take account current position of button:

if (e.button == mousebuttons.left) {     var b = ((button) sender);     b.location = new point(b.left + e.x, b.top + e.y); }