lion-tutorial20.htm

内有一些代码

  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; CW_USEDEFAULT,350,200,NULL,NULL,\</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; hInst,NULL</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp; mov&nbsp;&nbsp; hwnd,eax</b> <br>
  <b>&nbsp;&nbsp;&nbsp; .while TRUE</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke GetMessage, ADDR msg,NULL,0,0</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .BREAK .IF (!eax)</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke TranslateMessage, ADDR 
  msg</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke DispatchMessage, ADDR msg</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp; .endw</b> <br>
  <b>&nbsp;&nbsp;&nbsp; mov eax,msg.wParam</b> <br>
  <b>&nbsp;&nbsp;&nbsp; ret</b> <br>
  <b>WinMain endp</b> 
<p><b>WndProc proc hWnd:HWND, uMsg:UINT, wParam:WPARAM, lParam:LPARAM</b> <br>
  <b>&nbsp;&nbsp;&nbsp; .if uMsg==WM_CREATE</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke CreateWindowEx,WS_EX_CLIENTEDGE,ADDR 
  EditClass,NULL,\</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; WS_CHILD+WS_VISIBLE+WS_BORDER,20,\</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 20,300,25,hWnd,NULL,\</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; hInstance,NULL</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; mov hwndEdit,eax</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke SetFocus,eax</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ;-----------------------------------------</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ; Subclass it!</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ;-----------------------------------------</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke SetWindowLong,hwndEdit,GWL_WNDPROC,addr 
  EditWndProc</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; mov OldWndProc,eax</b> <br>
  <b>&nbsp;&nbsp;&nbsp; .elseif uMsg==WM_DESTROY</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke PostQuitMessage,NULL</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp; .else</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke DefWindowProc,hWnd,uMsg,wParam,lParam</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ret</b> <br>
  <b>&nbsp;&nbsp;&nbsp; .endif</b> <br>
  <b>&nbsp;&nbsp;&nbsp; xor eax,eax</b> <br>
  <b>&nbsp;&nbsp;&nbsp; ret</b> <br>
  <b>WndProc endp</b> 
<p><b>EditWndProc PROC hEdit:DWORD,uMsg:DWORD,wParam:DWORD,lParam:DWORD</b> <br>
  <b>&nbsp;&nbsp;&nbsp; .if uMsg==WM_CHAR</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; mov eax,wParam</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .if (al>="0" &amp;&amp; al&lt;="9") 
  || (al>="A" &amp;&amp; al&lt;="F") || (al>="a" &amp;&amp; al&lt;="f") || al==VK_BACK</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .if al>="a" 
  &amp;&amp; al&lt;="f"</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
  sub al,20h</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .endif</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke 
  CallWindowProc,OldWndProc,hEdit,uMsg,eax,lParam</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ret</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .endif</b> <br>
  <b>&nbsp;&nbsp;&nbsp; .elseif uMsg==WM_KEYDOWN</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; mov eax,wParam</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .if al==VK_RETURN</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke 
  MessageBox,hEdit,addr Message,addr AppName,MB_OK+MB_ICONINFORMATION</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke 
  SetFocus,hEdit</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .else</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke 
  CallWindowProc,OldWndProc,hEdit,uMsg,wParam,lParam</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ret</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .endif</b> <br>
  <b>&nbsp;&nbsp;&nbsp; .else</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke CallWindowProc,OldWndProc,hEdit,uMsg,wParam,lParam</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ret</b> <br>
  <b>&nbsp;&nbsp;&nbsp; .endif</b> <br>
  <b>&nbsp;&nbsp;&nbsp; xor eax,eax</b> <br>
  <b>&nbsp;&nbsp;&nbsp; ret</b> <br>
  <b>EditWndProc endp</b> <br>
  <b>end start</b> 
<h3> Analysis:</h3>
<ul>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke SetWindowLong,hwndEdit,GWL_WNDPROC,addr 
  EditWndProc</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; mov OldWndProc,eax</b> 
</ul>
After the edit control is created, we subclass it by calling SetWindowLong, replacing 
the address of the original window procedure with our own window procedure. Note 
that we store the address of the original window procedure for use with CallWindowProc. 
Note the EditWndProc is an ordinary window procedure. 
<ul>
  <b>&nbsp; .if uMsg==WM_CHAR</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; mov eax,wParam</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .if (al>="0" &amp;&amp; al&lt;="9") 
  || (al>="A" &amp;&amp; al&lt;="F") || (al>="a" &amp;&amp; al&lt;="f") || al==VK_BACK</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .if al>="a" 
  &amp;&amp; al&lt;="f"</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
  sub al,20h</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .endif</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke 
  CallWindowProc,OldWndProc,hEdit,uMsg,eax,lParam</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ret</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .endif</b> 
</ul>
Within EditWndProc, we filter WM_CHAR messages. If the character is between 0-9 
or a-f, we accept it by passing along the message to the original window procedure. 
If it is a lower case character, we convert it to upper case by adding it with 
20h. Note that, if the character is not the one we expect, we discard it. We don't 
pass it to the original window proc. So when the user types something other than 
0-9 or a-f, the character just doesn't appear in the edit control. 
<ul>
  <b>&nbsp;&nbsp;&nbsp; .elseif uMsg==WM_KEYDOWN</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; mov eax,wParam</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .if al==VK_RETURN</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke 
  MessageBox,hEdit,addr Message,addr AppName,MB_OK+MB_ICONINFORMATION</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke 
  SetFocus,hEdit</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .else</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; invoke 
  CallWindowProc,OldWndProc,hEdit,uMsg,wParam,lParam</b> <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ret</b> 
  <br>
  <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; .end</b> 
</ul>
I want to demonstrate the power of subclassing further by trapping Enter key. 
EditWndProc checks WM_KEYDOWN message if it's VK_RETURN (the Enter key). If it 
is, it displays a message box saying "You pressed the Enter key in the text box!". 
If it's not an Enter key, it passes the message to the original window procedure. 
<br>
You can use window subclassing to take control over other windows. It's one of 
the powerful techniques you should have in your arsenal.
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