What is IViewObject and How is it Used in C#

Question

I'm trying to do a few internet explorer automation tasks and it's requiring me to use IViewObject. What is IViewObject? Where can I find it's definition?

I've been google-ing and everything I find has a different interface definition for IViewObject. Different methods or different parameters going into the same methods.

How do I know what interface definition to use with internet explorer?

This is one definition I found on pinvoke.net

[GuidAttribute( "0000010d-0000-0000-C000-000000000046" )]
[InterfaceTypeAttribute( ComInterfaceType.InterfaceIsIUnknown )]
[ComImportAttribute()]
public interface IViewObject
{
    void Draw( [MarshalAs( UnmanagedType.U4 )] int dwDrawAspect, int lindex, IntPtr pvAspect, DVTARGETDEVICE ptd, IntPtr hdcTargetDev, IntPtr hdcDraw, COMRECT lprcBounds, COMRECT lprcWBounds, IntPtr pfnContinue, int dwContinue );
    int GetColorSet( [MarshalAs( UnmanagedType.U4 )] int dwDrawAspect, int lindex, IntPtr pvAspect, DVTARGETDEVICE ptd, IntPtr hicTargetDev, out tagLOGPALETTE ppColorSet );
    int Freeze( [MarshalAs( UnmanagedType.U4 )] int dwDrawAspect, int lindex, IntPtr pvAspect, out IntPtr pdwFreeze );
    int Unfreeze( [MarshalAs( UnmanagedType.U4 )] int dwFreeze );
    int SetAdvise( [MarshalAs( UnmanagedType.U4 )] int aspects, [MarshalAs( UnmanagedType.U4 )] int advf, [MarshalAs( UnmanagedType.Interface )] IAdviseSink pAdvSink );
    void GetAdvise( [MarshalAs( UnmanagedType.LPArray )] out int[] paspects, [MarshalAs( UnmanagedType.LPArray )] out int[] advf, [MarshalAs( UnmanagedType.LPArray )] out IAdviseSink[] pAdvSink );
}

I would just try this definition, but I get a few types that are unknown: DVTARGETDEVICE, COMRECT, tagLOGPALETTE. So my next question is, what assembly needs to be referenced to use these types?

Answer 1

DVTARGETDEVICE and COMRECT are structures. You can find their definitions on pinvoke.net.

tagLOGPALETTE is a class. There is a sample available at http://blogs.msdn.com/vsod/archive/2008/11/01/resizing-the-embedded-ole-objects-using-net.aspx.

In addition, IViewObject and the three referenced types are all used internally by the .NET Framework. If you grab yourself a copy of Reflector (http://www.red-gate.com/products/reflector/), you can view existing implementations in System.Windows.Forms.UnsafeNativeMethods.