获取Windows用户所有的账户名

/// <summary>
/// 设置用户密码
/// </summary>
[DllImport("Netapi32.dll")]
extern static int NetUserEnum([MarshalAs(UnmanagedType.LPWStr)] string sName,int Level,int filter,out IntPtr bufPtr,int Prefmaxlen, out int Entriesread,out int Totalentries,out int Resume_Handle);
[DllImport("Netapi32.dll")]
extern static int NetApiBufferFree(IntPtr Buffer);
/*
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct LOCALGROUP_USERS_INFO_0
{
public string GroupName;
}
*/
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct USER_INFO_1
{
public string sName;    //用户名
public string sPass;    //用户密码
public int PasswordAge; //密码级别
public int sPriv;       //帐户类型 1
public string sHomeDir; //用户主目录 null
public string sComment; //用户描述
public int sFlags;      //用户权限
public string sScriptPath;  //登陆脚本路径 null
}
public List<string> UserEnum()
{
List<String> listNames = new List<string>();
int Entriesread;
int TotalEntries;
int Resume_Handle;
IntPtr bufPtr;
if (NetUserEnum(null, 1, 0, out bufPtr, -1, out Entriesread, out TotalEntries, out Resume_Handle) != 0)
{
throw (new Exception("枚举全部用户失败"));
}
if (Entriesread > 0)
{
USER_INFO_1[] UserInfo = new USER_INFO_1[Entriesread];
IntPtr iter = bufPtr;
for (int i = 0; i < Entriesread; i++)
{
UserInfo[i] = (USER_INFO_1)Marshal.PtrToStructure(iter,  typeof(USER_INFO_1));
iter = (IntPtr)((int)iter + Marshal.SizeOf(typeof(USER_INFO_1)));
listNames.Add(UserInfo[i].sName);

}
}
NetApiBufferFree(bufPtr);
return listNames;
}