c# - How to prevent user to add control on specific location? -

previously have posted question how create non-client area? , got answer. now, want prevent user add control on specific client area.so, user can add control on allocated portion of client area.

the control should looked this.

class design & codes

xwizardcontrol: main user control placed on form.

xwizardpagewindow: container contains xwizardpages. control placed on xwizardcontrol. user add pages control collection dialog window.

xwizardpagecollection: collection of xwizardpage.

xwizardpage: user place other controls here.

xwizardpagedesigner: control designer xwizardpage control

you're setting nonclient rectangle incorrectly.

"on entry, structure contains proposed window rectangle window. on exit, structure should contain screen coordinates of corresponding window client area." -msdn-

also notice rect structure ltrb rectangle , not xywh rectangle.

incorrect

you shouldn't set values explicit:

ncrect.top = 68; //<---- ncrect.left = 176; //<---- ncrect.bottom -= 68;  ncparams.rectproposed.top = 68; //<---- ncparams.rectproposed.left = 176; //<---- ncparams.rectproposed.bottom -= 68; 

correct

but rather add (+=) or subtract (-=) to/from rectangle:

ncrect.top += 30; //<---- 30px top-margin ncrect.left += 50; //<---- 50px left-margin ncrect.bottom -= 20; //<---- 20px bottom-margin  ncparams.rectproposed.top += 30; ncparams.rectproposed.left += 50; ncparams.rectproposed.bottom -= 20; 

note

if don't paint nonclient area correctly, , control placed @ lets location -5, -5, control may appear if it's inside nonclient area.