为什么SHFileExists总会返回False?解决办法

为什么SHFileExists总会返回False?????

VB.NET code

Private Declare Function SHFileExists Lib "shell32" Alias "#45" (ByVal szPath As String) As Long

VB.NET code

Private Declare Function SearchTreeForFile Lib "dbghelp.dll" (ByVal RootPath As String, ByValputPathName As String, ByValputPathBuffer As String) As Long