_TEXT,
(HINSTANCE) GetWindowLong (hwnd, GWL_HINSTANCE),
NULL) ;
FillListBox (hwndList) ;
return 0 ;
case WM_SETFOCUS :
SetFocus (hwndList) ;
return 0 ;
case WM_COMMAND :
if (LOWORD (wParam) == ID_LIST && HIWORD (wParam) == LBN_SELCHANGE)
{
// Get current selection.
iIndex = SendMessage (hwndList, LB_GETCURSEL, 0, 0) ;
iLength = SendMessage (hwndList, LB_GETTEXTLEN, iIndex, 0) + 1 ;
pVarName = calloc (iLength, sizeof (TCHAR)) ;
SendMessage (hwndList, LB_GETTEXT, iIndex, (LPARAM) pVarName) ;
// Get environment string.
iLength = GetEnvironmentVariable (pVarName, NULL, 0) ;
pVarValue = calloc (iLength, sizeof (TCHAR)) ;
GetEnvironmentVariable (pVarName, pVarValue, iLength) ;
// Show it in window.
SetWindowText (hwndText, pVarValue) ;
free (pVarName) ;
free (pVarValue) ;
}
return 0 ;
case WM_DESTROY :
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}
ENVIRON建立两个子视窗：一个是LBS_STANDARD样式的清单方块，另一个是SS_LEFT样式（置左对齐文字）的静态视窗。ENVIRON使用函式GetEnvironmentStrings来获得一个指标，该指标指向存有全部环境变数名及其值的记忆体区块。ENVIRON用FillListBox函式来分析此记忆体区块，并使用LB_ADD |