c# - I want a functionality using .net to select an area by dragging at runtime -

i trying code in .net select area , area ever in form, not restricted control , asusually area appears square dragging using mouse @ runtime on form , if on clicking on button ex "save" i.e., saving selected area , when next time page loads particular area should clickable.right have no idea start if idea given more helpful me develop code functionality. 1 give small idea how can functionality, can proceed developing code?

this not code ... select area

  public partial class form1 : form         {             bool canresize;             int mx, my;             rectangle rect = new rectangle();              public form1()             {                 initializecomponent();             }              private void form1_paint(object sender, painteventargs e)             {                 e.graphics.drawrectangle(new pen(brushes.purple, 2), rect);             }              private void form1_mousedown(object sender, mouseeventargs e)             {                 canresize = true;                 mx = e.x; = e.y;                  rect.location = new point(mx, my);             }              private void form1_mouseup(object sender, mouseeventargs e)             {                 canresize = false;             }              private void form1_mousemove(object sender, mouseeventargs e)             {                 if (canresize)                 {                     if (mx < e.x)                     {                         rect.x = mx;                         rect.width = e.x - mx;                     }                     else                     {                         rect.x = e.x;                         rect.width = mx - e.x;                     }                     if (my < e.y)                     {                         rect.y = my;                         rect.height = e.y - my;                     }                     else                     {                         rect.y = e.y;                         rect.height = - e.y;                     }                     this.invalidate();                 }             }         }