長時間執行操作,顯示等待表徵圖.

長時間執行操作,顯示等待表徵圖.

如果程式中,需要進行長時間等待操作,可以顯示等待表徵圖,這樣可以給人更好的體驗.
在WIN32中,主要有SetCursor()函數來設定顯示的表徵圖.
在MSDN中對該函數的說明為:
HCURSOR SetCursor(
  HCURSOR hCursor
);
hCursor
[in] Handle to the cursor. The cursor must have been created by the CreateCursor or loaded by the LoadCursor or LoadImage function. If this parameter is NULL, the cursor is removed from the screen.

The width and height of the cursor must be the values returned by the GetSystemMetrics function for SM_CXCURSOR and SM_CYCURSOR.

而裡面需要用到LoadCursor()函數,
HCURSOR LoadCursor(
  HINSTANCE hInstance,
  LPCTSTR lpCursorName
);
To use one of the Microsoft Win32 predefined cursors, the application must set the hInstance parameter to NULL and the lpCursorName parameter to a specific value. The following table shows the possible values. This parameter must be set to one of these values.

Value  Description 
IDC_APPSTARTING
 Standard arrow and small hourglass.
 
IDC_ARROW
 Standard arrow.
 
IDC_CROSS
 Crosshair.
 
IDC_HAND
 Hand.
 
IDC_HELP
 Arrow and question mark.
 
IDC_ICON
 Obsolete.
 
IDC_NO
 Slashed circle.
 
IDC_SIZE
 Obsolete; use IDC_SIZEALL.
 
IDC_SIZEALL
 Four-pointed arrow pointing north, south, east, and west.
 
IDC_SIZENESW
 Double-pointed arrow pointing northeast and southwest.
 
IDC_SIZENS
 Double-pointed arrow pointing north and south.
 
IDC_SIZENWSE
 Double-pointed arrow pointing northwest and southeast.
 
IDC_SIZEWE
 Double-pointed arrow pointing west and east.
 
IDC_UPARROW
 Vertical arrow.
 
IDC_WAIT
 Hourglass.
 
因此要用顯示系統的等待表徵圖,可以為
SetCursor(LoadCursor(NULL, IDC_WAIT));
然後在結束的時候再把預設表徵圖切換回來.
SetCursor(LoadCursor(NULL, IDC_ARROW));