INFO: How Visual Basic Automation Statements Map to OLE Calls

MORE INFORMATION

The code listed below does not do any error checking. When you implement it, you should add the code to do necessary error checking. See the OLE SDK documentation for more information about each function or interface. Each code listing shows how to obtain the pointer to IDispatch of an Automation object in the pdisp variable.

CreateObject(progID)

This creates a new automation object and returns a pointer to the IDispatch of that object.

CLSID clsid;
LPUNKNOWN punk;
LPDISPATCH pdisp;

OleInitialize(NULL), if OLE isn't already loaded.
CLSIDFromProgID(progID, &clsid);
CoCreateInstance(clsid, NULL, CLSCTX_SERVER,
                 IID_IUnknown, (LPVOID FAR*)&punk);
punk->QueryInterface(IID_IDispatch, (LPVOID FAR*)&pdisp);
punk->Release();
				

GetObject(filename, progID)

GetObject has three different semantics depending on the number of parameters passed. An automation object must implement IPersistFile to support GetObject(filename, progID).

CLSID clsid;
LPUNKNOWN punk;
LPDISPATCH pdisp;
LPPERSISTFILE pPF;

OleInitialize(NULL), if OLE isn't already loaded
CLSIDFromProgID(progID, &clsid);
CoCreateInstance(clsid, NULL, CLSCTX_SERVER,
                 IID_IUnknown, (LPVOID FAR*)&punk);
punk->QueryInterface(IID_IPersistFile, (LPVOID FAR*)&pPF);
punk->Release();

pPF->Load(filename, 0);
pPF->QueryInterface(IID_IDispatch, (LPVOID FAR*)&pdisp);
pPF->Release();
				

GetObject(filename,)

GetObject has three different semantics depending on the number of parameters passed. An automation object must implement IPersistFile to support GetObject(filename,).

LPBC pbc;
ULONG cEaten;
LPMONIKER pmk;
LPDISPATCH pdisp;

OleInitialize(NULL), if OLE isn't already loaded
CreateBindCtx(0, &pbc);
MkParseDisplayName(pbc, filename, &cEaten, &pmk);
BindMoniker(pmk, 0, IID_IDispatch, (LPVOID FAR*)&pdisp);
pmk->Release();
pbc->Release();
				

GetObject(, progID)

GetObject has three different semantics depending on the number of parameters passed. An automation object must call RegisterActiveObject to support GetObject(, progID).

CLSID clsid;
LPUNKNOWN punk;
LPDISPATCH pdisp;

OleInitialize(NULL), if OLE isn't already loaded
CLSIDFromProgID(progID, &clsid);
GetActiveObject(clsid, NULL, (LPVOID FAR*)&punk);
punk->QueryInterface(IID_IDispatch, (LPVOID FAR*)&pdisp);
punk->Release();