?? getdcex.htm
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<title>GetDCEx</title>
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<td width="100%" height="16"><a name="GetDCEx">GetDCEx</a></td>
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<td width="103%" colspan="3">VB聲明</td>
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<td width="103%" colspan="3">Declare Function GetDCEx Lib "user32" Alias
"GetDCEx" (ByVal hwnd As Long, ByVal hrgnclip As Long, ByVal fdwOptions As Long)
As Long</td>
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<td width="103%" colspan="3">說(shuō)明</td>
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<td width="103%" colspan="3">為指定窗口獲取設(shè)備場(chǎng)景。相比<a href="GetDC.htm">GetDC</a>，本函數(shù)提供了更多的選項(xiàng)</td>
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<td width="103%" colspan="3">返回值</td>
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<td width="103%" colspan="3">Long，執(zhí)行成功為指定窗口設(shè)備場(chǎng)景句柄。出錯(cuò)則為0</td>
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<td width="103%" colspan="3">參數(shù)表</td>
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<td width="25%">參數(shù)</td>
<td width="78%" colspan="2">類型及說(shuō)明</td>
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<td width="25%">hwnd</td>
<td width="78%" colspan="2">Long，窗口句柄</td>
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<td width="25%">hrgnclip</td>
<td width="78%" colspan="2">Long，窗口剪裁區(qū)</td>
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<td width="25%" rowspan="13">fdwOptions</td>
<td width="78%" colspan="2">Long，標(biāo)志字。根據(jù)下列常數(shù)設(shè)置各位：</td>
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<td width="37%">DCX_CACHE</td>
<td width="38%">不管窗口類的樣式，從windows緩存獲取設(shè)備場(chǎng)景</td>
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<td width="37%">DCX_CLIPCHILREN</td>
<td width="38%">所有可見(jiàn)的子窗口區(qū)都要從DC的剪裁區(qū)中排除</td>
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<td width="37%">DCX_CLIPSIBLINGS</td>
<td width="38%">窗口hWnd上的所有可見(jiàn)兄弟窗口都要從DC的剪裁區(qū)中排除</td>
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<td width="37%">DCX_EXCLUDERGN</td>
<td width="38%">從DC剪裁區(qū)中排除由hrgnclip指定的區(qū)域</td>
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<td width="37%">DCX_EXCLUDEUPDATE</td>
<td width="38%">從設(shè)備場(chǎng)景剪裁區(qū)中排除刷新區(qū)域</td>
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<td width="37%">DCX_INTERSECTRGN</td>
<td width="38%">由hrgnclip指定的區(qū)域與設(shè)備場(chǎng)景剪裁區(qū)相交</td>
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<td width="37%">DCX_INTERSECTUPDATE</td>
<td width="38%">指定區(qū)域與設(shè)備場(chǎng)景刷新區(qū)域相交</td>
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<td width="37%">DCX_LOCKWINDOWUPDATE</td>
<td width="38%">該標(biāo)志為允許向窗口繪圖，即使它由于<a
href="LockWindowUpdate.htm">LockWindowUpdate</a>的調(diào)用被鎖住</td>
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<td width="37%">DCX_NORESETATTRS</td>
<td width="38%">設(shè)備場(chǎng)景釋放后不被重置為默認(rèn)狀態(tài)</td>
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<td width="37%">DCX_PARENTCLIP</td>
<td width="38%">放棄CS_PARENTDC類樣式設(shè)置。DC的起點(diǎn)設(shè)為hWnd窗口的左上角</td>
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<td width="37%">DCX_WINDOW</td>
<td width="38%">A device context is returned for the entire window rectangle rather than
just the client area of the window</td>
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<td width="37%">DCX_VALIDATE</td>
<td width="38%">Combine with DCX_INTERSECTUPDATE, validates the clipping region</td>
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<td width="103%" colspan="3">注解</td>
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<td width="103%" colspan="3"><p align="left">若窗口所屬類具有CS_OWNDC，
CS_CLASSDC 或 CS_PARENTDC樣式，則獲取的設(shè)備場(chǎng)景屬窗口或類專有。這時(shí)，設(shè)備場(chǎng)景狀態(tài)不能從初值修改。vb的窗體和控件通常是這種情況。否則，置DCX_CACHE位以從通用windows緩沖區(qū)恢復(fù)設(shè)備場(chǎng)景。若不置該位，則函數(shù)返回0。DC的狀態(tài)位默認(rèn)設(shè)置。從緩存獲取的設(shè)備場(chǎng)景用過(guò)后要用<a
href="ReleaseDC.htm">ReleaseDC</a>函數(shù)釋放以防止系統(tǒng)死鎖，因?yàn)閣indows只有5個(gè)緩存DC可用<br>
其他情況參見(jiàn)<a href="GetDC.htm">GetDC</a>函數(shù)注解</td>
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<td width="100%"><p align="right"><a href="#GetDCEx">Top</a></td>
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