ITypeInfo::Invoke

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

This method invokes a method or accesses a property of an object that implements the interface indicated by the type description.

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
  [in] Pointer to an instance of the interface described by this type description.

• memid
  [in] Identifier of the interface member.

• wFlags
  [in] 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
  [in, out] 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
  [out] 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, pVarResult is ignored.

• pExcepInfo
  [out] Pointer to an exception information structure, which is filled in only if DISP_E_EXCEPTION is returned. If pExcepInfo is NULL on input, only an HRESULT error is returned.

• puArgErr
  [out] If ITypeInfo::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 Value

The following table shows the return values for this function.

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 ITypeInfo::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.

Requirements

See Also

Reference

ITypeInfo
IDispatch
IDispatch::Invoke
IErrorInfo