How do I play an AVI file in DirectX 9 (VB.NET)?

DirectShow can work natively with Direct3D surfaces, however I'm not sure what its availability is for managed apps. I don't think an official managed interface exists for it, but I'm not sure.

EDIT: some searching on Google shows that people have made or are working on managed wrappers for DirectShow.

I'm not sure if I'm using managed DX, I'd have to check... I can't remember the difference between managed and unmanaged... I don't use D3DX at all. I'm using VertexBuffers instead of meshes. I'm going to check DirectShow now =D

VB.NET is .NET-only (hence the name), which means it can only produce managed code.

You'll want to use Microsoft.DirectX.AudioVideoPlayback
for that.

^^ Yes, in particular the Video class.

You could use something like this (C# code):

Video v = null;

.......

//the constructor takes a string witch is the path to the filename
v = new Video(pathtofile);
//owner window; if null then the video class will create a new window
v.Owner = this;
//true for fullscreen
v.Fullscreen = true;
//begin playback
v.Play();