How to call a .NET COM method with an array from delphi using PSafeArray?

Question

I have an .NET (4.0) interface which is implemented with a ServicedComponent COM+ class:

interface DotNetIface
{
    void MethodRef(var System.Guid guid);
    void MethodArray(System.Guid[] guids, params object[] parameters);
    void MethodCStyle([MarshalAs(UnmanagedType.LPArray, ArraySubType=UnmanagedType.Struct, SizeConst=5)]System.Guid[] guids);
}

Now I used the Delphi 2007 import wizard to import the type library, and as expected I get the following signatures:

procedure MethodRef(var guid : TGuid);
procedure MethodArray(guids : PSafeArray);
procedure MethodCStyle(var guids : ClrGuid /* from mscorlib_TLB */);

If i now call the "ref" method like this it works fine:

procedure CallByRef(guid : TGuid);
var
    test : TGuid;
begin
    test := ...
    comRef.MethodRef(guid);
end;

Now I also need the array method

procedure CallArray();
var
    localGuid : TGuid;
    arrayVariant : OleVariant;
begin
    arrayVariant := VarArrayCreate([0,4], varVariant /* dont know here */);
    arrayVariant[0] := localGuid; /* compile error, cannot cast implicitly */

    comRef.MethodArray(PSafeArray(TVarData(arrayVariant.VArray)), /* here this object... PSafeArray works actually*/);
end;

Now lastly i tried with a c array

procedure CallCStyle();
var
    localGuid : TGuid;
    arrayOfGuid : array [0..4] of ClrGuid;
begin
    arrayOfGuid[0] := ClrGuid(localGuid);

    comRef.MethodCStyle(PSafeArray(/* now i dont know put it*/, /* here this object... PSafeArray works actually*/);
end;

I seriously dont know how to make this work. I hope someone has more experience with COM marshalling thx

Side node:

I found VT_CLSID which i think can be passed for SafeArrayCreate, but I am not sure how to sue that

Answer 1

I have never tried what you need but a quick search found the following articles:

• Scripting Your Delphi Applications (Shows a Good example of converting a variant array to PSafeArray
• How to do a SafeArray Access with a DLL for Variants (OLE)
• The mysteries of PSafeArray