in C#, changing background image of a button after click -

this code not report error , should have work.the button background image not change. idea of wrong?

    void myhandler(object sender, eventargs e, string val)     {         //process         process.start(@val);         //change button bkground image         var button = (button)sender;         button.backgroundimage = global::test.properties.resources.impok;     } 

edit event myhandler being called buttons created event handler.

 private async void button3_click(object sender, eventargs e)       {         ...             foreach (keyvaluepair<string, string> pair in printerdic)             {                 //init                 string val = pair.value;                 string ky = pair.key;                  //button                 button bt_imp = new button();                 if (list_localservprnlink.contains(val))                 {                     bt_imp.backgroundimage = global::test.properties.resources.impok;                 }                 else                 {                     bt_imp.backgroundimage = global::test.properties.resources.impx;                 }                               bt_imp.size = new system.drawing.size(30, 30);                 bt_imp.location = new point(horizotal, vertical - bt_imp.height / 2);                 bt_imp.click += (s, ea) => { myhandler(sender, e, val); };//passing printer instal link when click                  ...                 vertical += 30;//prochaine ligne...                  this.invoke((methodinvoker)delegate { // runs on ui thread,                     tabpage1.controls.add(bt_imp);                     tabpage1.controls.add(lb_impbt);                 });              } 

... }

this line have in button3_click handler incorrect:

bt_imp.click += (s, ea) => { myhandler(sender, e, val); }; 

what doing right capturing sender/event arguments calling method. want let myhandler sender/arguments bt_imp click, need change to:

bt_imp.click += (s, ea) => { myhandler(s, ea, val); }; 

which named parameters in anonymous method.

the second thing need make sure invoke ui changes on ui thread. quite in button3_click handler, missed in myhandler routine, invoke background change on ui thread:

this.invoke((methodinvoker)delegate { // runs on ui thread,                     button.backgroundimage = global::test.properties.resources.impok;                 }); 

and should take care of it.