.NET mshtml: How to pass a BSTR SAFEARRAY?

Question

The class mshtml.HTMLDocumentClass in Microsoft.mshtml.dll assembly has a method:

public virtual void write(params object[] psarray);

Avoiding

Answer 1

The params keyword indicates that you can supply multiple parameters in this place, and it will group automatically. For example, if I had a function thus:

public int SumNumbers(params int[] value)
{
       //Logic.
}

then I could call it like this:

int myValue = SumNumbers(1,2,3,4,5,6,7,8,9,10);

The array is constructed automagically. So hypothetically, you could call

mshtml.HTMLDocumentClass doc;
...
doc.write('H','I',' ','M','O','M');

And it would work. Not really practical though. I suppose you've tried calling

doc.write(myString.ToCharArray());

? I don't know anything about SAFEARRAYS, but its possible you might not have to know, either, depending on how the compiler helps/hinders here.

Answer 2

The declaration for the write method on the IHTMLDocument2 interface created by TLBIMP/VS.NET is incorrect. It should be:

void Write([In, MarshalAs(UnmanagedType.SafeArray)] object[] psarray);

You will have to define this interface in code and then use that.

Answer 3

It works like a charm this way :

[Guid("332C4425-26CB-11D0-B483-00C04FD90119")]
[ComImport]
[TypeLibType((short)4160)]
[InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIDispatch)]
internal interface IHTMLDocument2
{
    [DispId(1054)]
    void write([MarshalAs(UnmanagedType.BStr)] string psArray); //modified 
    //void write([MarshalAs(UnmanagedType.SafeArray, SafeArraySubType = VarEnum.VT_VARIANT)] object[] psarray); //instead of