C # winform: Use the scroll wheel to control the image size and obtain the scroll wheel and mousewheel events in the middle mouse.

First, add this sentence to the form constructor.
C # Code

1. This. Mousewheel + =NewSystem. Windows. Forms. mouseeventhandler (This. Panelappsmousewheel );

 
This. mousewheel + = new system. Windows. Forms. mouseeventhandler (this. panel?mousewheel );
 

C # code

2. # Loading when region enters the form
6. PublicFormalarminfoquery ()
8. {
10. Initializecomponent ();
12. Picturebox1.imagelocation ="F: \ 1.jpg";
16. This. Mousewheel + =NewSystem. Windows. Forms. mouseeventhandler (This. Panelappsmousewheel );
18. // Determine whether a mouse with a scroll wheel is installed
20. // Systeminformation. mousewheelpresent. tostring ();
22. // Obtain the number of rows of the scroll wheel.
24. // Systeminformation. mousewheelscrolllines. tostring ();
26. // Determine whether the operating system supports scroll mouse
28. // Systeminformation. nativemousewheelsupport. tostring ();
30. } 
34. # Endregion

 
# When region enters the form, it loads public formalarminfoquery () {initializecomponent (); picturebox1.imagelocation = "F: \ 1.jpg"; this. mousewheel + = new system. windows. forms. mouseeventhandler (this. panelappsmousewheel); // determines whether a mouse with a scroll wheel is installed. // systeminformation. mousewheelpresent. tostring (); // obtain the number of rows obtained when the scroll wheel is scroll. // systeminformation. mousewheelscrolllines. tostring (); // determines whether the operating system supports scroll wheel and mouse. // systeminformation. nativemousewheelsupport. tostring () ;}# endregion
 

Then write a mouse event Method

C # code

2. Private VoidPanelappsmousewheel (ObjectSender, system. Windows. Forms. mouseeventargs E)
4. {
6. MessageBox. Show ("Rolling event captured");
8. System. Drawing. Size T = picturebox1.size;
10. T. Width + = E. Delta;
12. T. height + = E. Delta;
14. Picturebox1.width = T. width;
16. Picturebox1.height = T. height;
18. }

 
Private void panelappsmousewheel (Object sender, system. windows. forms. mouseeventargs e) {MessageBox. show ("rolling event captured"); system. drawing. size T = picturebox1.size; T. width + = E. delta; T. height + = E. delta; picturebox1.width = T. width; picturebox1.height = T. height ;}
 

If the "rolling event captured" is output, the scroll wheel event is captured successfully, and you can write the event to be handled by the scroll wheel.