This method invokes a method or accesses a property of an object that implements the interface indicated by the type description.
At a Glance
| Header file: | Oaidl.h |
| Windows CE versions: | 2.0 and later |
Syntax
HRESULT Invoke( VOID FAR* pvInstance, MEMBERID memid,
unsigned short wFlags, DISPPARAMS FAR* pDispParams,
VARIANT FAR* pVarResult, EXCEPINFO FAR* pExcepInfo,
unsigned int FAR* puArgErr );
Parameters
pvInstance
Pointer to an instance of the interface described by this type description.
memid
Identifier of the interface member.
wFlags
Flags that describe the context of the invoke call. It is one of the following values:
| Value | Description |
| DISPATCH_METHOD | The member is accessed as a method. If there is ambiguity, both this and the DISPATCH_PROPERTYGET flag can 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 using a reference assignment, rather than a value assignment. This value is only valid when the property accepts a reference to an object. |
pDispParams
Pointer to a structure that contains an array of parameters, an array of DISPIDs for named parameters, and counts of the number of elements in each array.
pVarResult
Should be NULL if the caller does not expect any result. Otherwise, it should be a pointer to the location at which the result is to be stored. If wFlags specifies DISPATCH_PROPERTYPUT or DISPATCH_PROPERTYPUTREF, pVarResultis ignored.
pExcepInfo
Points to an exception information structure, which is filled in only if DISP_E_EXCEPTION is returned. If pExcepInfois NULL on input, only an HRESULT error is returned.
puArgErr
If Invoke returns DISP_E_TYPEMISMATCH, puArgErr indicates the index (within rgvarg) of the parameter with incorrect type. If more than one parameter returns an error, puArgErr indicates only the first parameter with an error. Arguments in pDispParams->rgvarg appear in reverse order, so the first parameter is the one having the highest index in the array. Cannot be NULL.
Return Values
One of the values described in the following table is returned.
| Value | Description |
| S_OK | Success. |
| E_INVALIDARG | One or more of the parameters is invalid. |
| DISP_E_EXCEPTION | The member being invoked has returned an error HRESULT. If the member implements IErrorInfo, details are available in the error object. Otherwise, the pExcepInfo parameter contains details. |
| TYPE_E_IOERROR | The function could not read from the file. |
| TYPE_E_INVDATAREAD | Invalid data. |
| TYPE_E_UNSUPFORMAT | The type library has an older format. |
| TYPE_E_REGISTRYACCESS | There was an error accessing the system registration database. |
| TYPE_E_LIBNOTREGISTERED | The type library was not found in the system registration database. |
| TYPE_E_INVALIDSTATE | The type library could not be opened. |
| TYPE_E_WRONGTYPEKIND | Type mismatch. |
| TYPE_E_ELEMENTNOTFOUND | The element was not found. |
| TYPE_E_BADMODULEKIND | The module does not support Invoke. |
| Other return codes | Any of the IDispatch::Invoke errors may also be returned. |
Remarks
Use the function ITypeInfo::Invoke to access a member of an object or invoke a method that implements the interface described by this type description. For objects that support the IDispatch interface, you can use Invoke to implement IDispatch::Invoke.
ITypeInfo::Invoke takes a pointer to an instance of the class. Otherwise, its parameters are the same as IDispatch::Invoke, except that ITypeInfo::Invoke omits the refiid and lcid parameters. When called, ITypeInfo::Invoke performs the actions described by the IDispatch::Invoke parameters on the specified instance.
For VTBL interface members, ITypeInfo::Invoke passes the LCID of the type information into parameters tagged with the lcid attribute, and the returned value into the retval attribute.
If the type description inherits from another type description, this function recurses on the base type description to find the item with the requested member identifier.