C# Signature:

[DllImport("CfgMgr32.dll")]
public static extern UInt32 CM_Get_DevNode_Property(
     UInt32 dnDevInst,
     ref DEVPROPKEY PropertyKey,
     out DEVPROPTYPE PropertyType,
     IntPtr PropertyBuffer,
     ref UInt32 PropertyBufferSize,
     UInt32 ulFlags);
[DllImport("CfgMgr32.dll", CharSet = CharSet.Unicode)]
public static extern UInt32 CM_Get_DevNode_Property(
     UInt32 dnDevInst,
     ref DEVPROPKEY PropertyKey,
     out DEVPROPTYPE PropertyType,
     StringBuilder PropertyBuffer,
     ref UInt32 PropertyBufferSize,
     UInt32 ulFlags);

User-Defined Types:

struct DEVPROPKEY {
     public Guid guid;
     public UInt32 pid;
}

Sample Code: