-
InvokeHelper
鎖定
當在項目中插入ActiveX控件ClassWizard生成的CWnd的派生類時,在C++類中可以看到其成員函數的代碼中都有對InvokeHelper函數的調用,InvokeHelper函數的第一個參數都和對應的屬性或方法在ActiveX控件中的分發(dispatch)ID(標識ActiveX控件的方法或屬性的)相對應。
- 中文名
- InvokeHelper
- 類 別
- 函數
- 用 途
- 調用其生成的C++類成員函數相關
- 所屬分類
- C++類
其他信息
下面對InvokeHelper單獨説明:
CWnd::InvokeHelper
void InvokeHelper( DISPID dwDispID, WORD wFlags, VARTYPE vtRet, void* pvRet, const BYTE* pbParamInfo, ... );
説明:
Call this member function to invoke the OLE control method or property specified by dwDispID, in the context specified by wFlags.
其中參數:
dwDispID:
//Identifies the method or property to be invoked. This value is usually supplied by Component Gallery.
wFlags:可以為下面些值,指明調用InvokeHelper的目的。
//[ DISPATCH_METHOD ] The member is invoked as a method. If a property has the same name, both this and the DISPATCH_PROPERTYGET flag may be set.
[ DISPATCH_PROPERTYGET ] The member is retrieved as a property or data member.
[ DISPATCH_PROPERTYPUT ] The member is changed as a property or data member.
[ DISPATCH_PROPERTYPUTREF ] The member is changed by a reference assignment, rather than a value assignment. This flag is valid only when the property accepts a reference to an object.
vtRet:
//Specifies the type of the return value.
VT_EMPTY void
VT_I2 short
VT_I4 long
VT_R4 float
VT_R8 double
VT_CY CY
VT_DATE DATE
VT_BSTR BSTR
VT_DISPATCH LPDISPATCH
VT_ERROR SCODE
VT_BOOL BOOL
VT_VARIANT VARIANT
VT_UNKNOWN LPUNKNOWN
pvRet:
//Address of the variable that will receive the property value or return value. It must match the type specified by vtRet.
pbParamInfo:一般都設置為NULL
//Pointer to a null-terminated string of bytes specifying the types of the parameters following pbParamInfo.
specifies the types of the parameters passed to the method or property.
...:
//Variable List of parameters, of types specified in pbParamInfo.
InvokeHelper()函數的用法
1、播放文件的函數:
void CActiveMovie3::Run()
{ InvokeHelper(0x60020001, DISPATCH_METHOD, VT_EMPTY, NULL, NULL); }
2、暫停播放的函數: void CActiveMovie3::Pause()
{ InvokeHelper(0x60020002, DISPATCH_METHOD, VT_EMPTY, NULL, NULL); }
3、停止播放的函數: void CActiveMovie3::Stop()
{ InvokeHelper(0x60020003, DISPATCH_METHOD, VT_EMPTY, NULL, NULL); }
4、獲得文件的函數: CString CActiveMovie3::GetFileName()
{ CString result; InvokeHelper(0xb, DISPATCH_PROPERTYGET, VT_BSTR, (void*)&result, NULL); return result; }
5、設置文件的函數: void CActiveMovie3::SetFileName(LPCTSTR lpszNewValue)
{ static BYTE parms[] = VTS_BSTR; InvokeHelper(0xb, DISPATCH_PROPERTYPUT, VT_EMPTY, NULL, parms, lpszNewValue); }
6、獲得播放位置的函數: double CActiveMovie3::GetCurrentPosition()
{ double result; InvokeHelper(0xd, DISPATCH_PROPERTYGET, VT_R8, (void*)&result, NULL); return result; }
7、設置播放位置的函數: void CActiveMovie3::SetCurrentPosition(double newValue)
{ static BYTE parms[] = VTS_R8; InvokeHelper(0xd, DISPATCH_PROPERTYPUT, VT_EMPTY, NULL, parms, newValue); }
8、獲得音量的函數: long CActiveMovie3::GetVolume()
{ long result; InvokeHelper(0x13, DISPATCH_PROPERTYGET, VT_I4, (void*)&result, NULL); return result; }
9、設置音量的函數: void CActiveMovie3::SetVolume(long nNewValue)
{ static BYTE parms[] = VTS_I4; InvokeHelper(0x13, DISPATCH_PROPERTYPUT, VT_EMPTY, NULL, parms, nNewValue); }
- 詞條統計
-
- 瀏覽次數:次
- 編輯次數:18次歷史版本
- 最近更新: JD萤火虫003