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GetDC

說明:
GetDC 函式可用來取得指定視窗工作區的裝置環境代碼(Device Context)


引用函式庫:
User32


適用系統:
Windows NT 3.1 或 Windows 95以上


函式原型:

Declare Function GetDC Lib "user32" Alias "GetDC" ( _
    ByVal hwnd As Long _
    ) As Long



參數型態及說明:
hwndLong 要取得裝置環境代碼(Device Context)的視窗代碼(Handle)

回傳值:
Long 呼叫成功的話,將會回傳指定視窗工作區的裝置環境代碼(Device Context);若呼叫失敗的話,則回傳 0

.NET Framework API:
System.Windows.Forms.Form.CreateGraphics.GetHdc
System.Drawing.Graphics.GetHdc


VB範例:

檢視原始碼 Visual Basic
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'VB的宣告
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)

RB範例:

檢視原始碼 REALBasic
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'RB的宣告
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)

VB.NET範例:

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'VB.NET的宣告
<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)

C#範例:

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//C#的宣告
[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);

註釋:
若是透過 GetDC 函式來取得的話,不用時要用 ReleaseDC 函式來釋放它

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