Loading a text file from assets

I have included a file... mytext.txt I want to load in to web veiw, but webview says

file://AssetsDir/mytext.txt was not found, there is not such file or directory.



Here is a snippet of my code....

WebView1.Initialize("WebView1")
activity.AddView(webview1,0dip, 0dip, 100%x, 100%y)
url="file:///" & File.DirAssets&"/mytext.txt"



What path should I be using, I thought File.DirAssets was the default path unless you specified otherwise?

Thanks in advance