# Handling events: OverlayDrawing, OverlayDrawn, OverlaysDrawing, OverlaysDrawn

**URL:** <https://community.thinkgeo.com/t/handling-events-overlaydrawing-overlaydrawn-overlaysdrawing-overlaysdrawn/498>\
**Category:** WinForms\
**Created:** [June 24, 2009, 5:00am UTC](https://community.thinkgeo.com/t/handling-events-overlaydrawing-overlaydrawn-overlaysdrawing-overlaysdrawn/498 "2009-06-24T05:00:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![wesolowski](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/w/90db22/32.png) [@wesolowski](https://community.thinkgeo.com/u/wesolowski)\
**Post date:** [June 24, 2009, 5:00am UTC](https://community.thinkgeo.com/t/handling-events-overlaydrawing-overlaydrawn-overlaysdrawing-overlaysdrawn/498/1 "2009-06-24T05:00:00Z")

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&nbsp;WinformsMap&nbsp;does&nbsp;not&nbsp;like&nbsp;too&nbsp;much&nbsp;data&nbsp;to&nbsp;draw.&nbsp;To&nbsp;reduce&nbsp;them&nbsp;I&nbsp;want&nbsp;to&nbsp;make&nbsp;some&nbsp;simplification&nbsp;trajectory&nbsp;of&nbsp;roads&nbsp;data.&nbsp;I&nbsp;would&nbsp;like&nbsp;to&nbsp;use&nbsp;event&nbsp;handlers&nbsp;which&nbsp;groups&nbsp;layers&nbsp;(and&nbsp;their&nbsp;data)&nbsp;to&nbsp;make&nbsp;this&nbsp;simplification,&nbsp;some&nbsp;data&nbsp;could&nbsp;I&nbsp;just&nbsp;skipped.&nbsp;

I&nbsp;am&nbsp;using&nbsp;event&nbsp;handlers&nbsp;before&nbsp;drawing&nbsp;process:&nbsp;OverlayDrawing,&nbsp;OverlaysDrawing&nbsp;but&nbsp;I&nbsp;do&nbsp;not&nbsp;see&nbsp;if&nbsp;these&nbsp;functions&nbsp;are&nbsp;called.&nbsp;

Api&nbsp;Documentation&nbsp;does&nbsp;not&nbsp;talk&nbsp;anything&nbsp;about&nbsp;how&nbsp;to&nbsp;use&nbsp;them&nbsp;and&nbsp;how&nbsp;they&nbsp;can&nbsp;be&nbsp;helpfull.

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**Author:** ![ThinkGeo](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/thinkgeo/32/25029_2.png) [@ThinkGeo](https://community.thinkgeo.com/u/ThinkGeo)\
**Post date:** [June 24, 2009, 8:04pm UTC](https://community.thinkgeo.com/t/handling-events-overlaydrawing-overlaydrawn-overlaysdrawing-overlaysdrawn/498/2 "2009-06-24T20:04:44Z")

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Pawel,&nbsp;  
&nbsp;&nbsp;  
&nbsp;Thanks&nbsp;for&nbsp;your&nbsp;post&nbsp;and&nbsp;welcome&nbsp;you&nbsp;ThinkGeo&nbsp;Desktop&nbsp;Forum!&nbsp;  
&nbsp;&nbsp;  
&nbsp;Just&nbsp;want&nbsp;to&nbsp;make&nbsp;sure&nbsp;which&nbsp;version&nbsp;of&nbsp;Desktop&nbsp;you&nbsp;are&nbsp;using&nbsp;now?&nbsp;  
&nbsp;&nbsp;  
&nbsp;I&nbsp;think&nbsp;the&nbsp;OverlayDrawing,&nbsp;OverlayDrawn,&nbsp;OverlaysDrawing,&nbsp;OverlaysDrawn&nbsp;4&nbsp;events&nbsp;will&nbsp;fired&nbsp;very&nbsp;decently,&nbsp;can&nbsp;you&nbsp;pasted&nbsp;some&nbsp;codes&nbsp;out&nbsp;to&nbsp;say&nbsp;why&nbsp;it&nbsp;is&nbsp;not&nbsp;fired?&nbsp;  
&nbsp;&nbsp;  
&nbsp;Sorry&nbsp;for&nbsp;the&nbsp;lack&nbsp;of&nbsp;the&nbsp;API&nbsp;docs&nbsp;now,&nbsp;all&nbsp;the&nbsp;4&nbsp;events&nbsp;naming&nbsp;are&nbsp;very&nbsp;close&nbsp;to&nbsp;the&nbsp;rule&nbsp;to&nbsp;Microsoft,&nbsp;so&nbsp;I&nbsp;think&nbsp;it&nbsp;is&nbsp;very&nbsp;easy&nbsp;to&nbsp;detect&nbsp;its&nbsp;usage:&nbsp;  
&nbsp;OverlaysDrawing:&nbsp;Will&nbsp;be&nbsp;fired&nbsp;before&nbsp;all&nbsp;the&nbsp;Overlays&nbsp;to&nbsp;be&nbsp;drawn&nbsp;  
&nbsp;OverlayDrawing:&nbsp;&nbsp;will&nbsp;be&nbsp;fired&nbsp;before&nbsp;the&nbsp;Overlay&nbsp;to&nbsp;be&nbsp;drawn&nbsp;  
&nbsp;OverlayDrawn&nbsp;:&nbsp;will&nbsp;be&nbsp;fired&nbsp;after&nbsp;the&nbsp;Overlay&nbsp;to&nbsp;be&nbsp;drawn.&nbsp;  
&nbsp;OverlaysDrawn:&nbsp;will&nbsp;be&nbsp;fired&nbsp;after&nbsp;all&nbsp;the&nbsp;Overlays&nbsp;to&nbsp;be&nbsp;drawn.&nbsp;  
&nbsp;&nbsp;  
&nbsp;Sorry&nbsp;for&nbsp;the&nbsp;inconvenience!&nbsp;  
&nbsp;Any&nbsp;more&nbsp;questions&nbsp;just&nbsp;let&nbsp;me&nbsp;know.&nbsp;  
&nbsp;&nbsp;  
&nbsp;Thanks.&nbsp;  
&nbsp;&nbsp;  
&nbsp;Yale&nbsp;