說明:
CreateCompatibleDC 函式在記憶體中建立指定的裝置環境代碼(Device Context)一樣的裝置環境
引用函式庫:
GDI32
適用系統:
Windows NT 3.1 或 Windows 95以上
函式原型:
Declare Function CreateCompatibleDC Lib "gdi32" Alias "CreateCompatibleDC" ( _ ByVal hdc As Long _ ) As Long
參數型態及說明:
hdc:Long 要在記憶體中建立的裝置環境代碼(Device Context)
回傳值:
Long 呼叫成功的話,將會回傳建立後的裝置環境代碼(Device Context);若呼叫失敗的話,則回傳 NULL
.NET Framework API:
System.Drawing.Graphics.FromHdc
VB範例:
檢視原始碼 Visual Basic
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | 'VB的宣告 Private Declare Function CreateCompatibleDC Lib "gdi32" ( _ ByVal hdc As Long _ ) As Long Private Declare Function ReleaseDC Lib "user32" ( _ ByVal hwnd As Long, _ ByVal hdc As Long _ ) As Long Private Declare Function GetDC Lib "user32" ( _ ByVal hwnd As Long _ ) As Long Dim hdc As Long '取得目前執行視窗的裝置環境代碼(Device Context) hdc = GetDC(Form1.hwnd) Dim mHdc As Long '在記憶體中建立一個指定裝置環境 mHdc = CreateCompatibleDC(hdc) Dim r As Long '釋放目前執行視窗的裝置環境代碼(Device Context) r = ReleaseDC(Form1.hwnd, hdc) |
RB範例:
檢視原始碼 REALBasic
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | 'RB的宣告 Declare Function CreateCompatibleDC Lib "gdi32" ( _ hdc As Integer _ ) As Integer Declare Function ReleaseDC Lib "user32" ( _ hwnd As Integer, _ hdc As Integer _ ) As Integer Declare Function GetDC Lib "user32" ( _ hwnd As Integer _ ) As Integer Dim hdc As Integer '取得目前執行視窗的裝置環境代碼(Device Context) hdc = GetDC(Window1.WinHWND) Dim mHdc As Integer '在記憶體中建立一個指定裝置環境 mHdc = CreateCompatibleDC(hdc) Dim r As Integer '釋放目前執行視窗的裝置環境代碼(Device Context) r = ReleaseDC(Window1.WinHWND, hdc) |
VB.NET範例:
檢視原始碼 VB.NET
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | 'VB.NET的宣告 <DllImport("gdi32.dll")> _ Shared Function CreateCompatibleDC( _ ByVal hdc As IntPtr _ ) As IntPtr End Function <DllImport("user32.dll")> _ Shared Function ReleaseDC( _ ByVal hwnd As IntPtr, _ ByVal hdc As IntPtr _ ) As UInteger End Function <DllImport("user32.dll")> _ Shared Function GetDC( _ ByVal hwnd As IntPtr _ ) As IntPtr End Function Dim hdc As IntPtr '取得目前執行視窗的裝置環境代碼(Device Context) hdc = GetDC(Me.Handle) Dim mHdc As IntPtr '在記憶體中建立一個指定裝置環境 mHdc = CreateCompatibleDC(hdc) Dim r As Integer '釋放目前執行視窗的裝置環境代碼(Device Context) r = ReleaseDC(Me.Handle, hdc) |
C#範例:
檢視原始碼 C#
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | //C#的宣告 [DllImport("gdi32")] public static extern IntPtr CreateCompatibleDC( IntPtr hdc ); [DllImport("user32")] public static extern uint ReleaseDC( IntPtr hwnd, IntPtr hdc ); [DllImport("user32")] public static extern IntPtr GetDC( IntPtr hwnd ); IntPtr hdc; //取得目前執行視窗的裝置環境代碼(Device Context) hdc = GetDC(this.Handle); IntPtr mHdc; //在記憶體中建立一個指定裝置環境 mHdc = CreateCompatibleDC(hdc); uint r; //釋放目前執行視窗的裝置環境代碼(Device Context) r = ReleaseDC(this.Handle, hdc); |
註釋:
若是 hdc 參數是 NULL 的話,則會建立目前應用程式畫面的裝置環境。不用時要用 DeleteDC 函式來釋放它