C# Signature:
[DllImport("wtsapi32.dll", SetLastError=true)]
static extern void WTSEnumerateSessions(
System.IntPtr hServer,
int Reserved,
int Version,
ref System.IntPtr ppSessionInfo,
ref int pCount);
static extern void WTSEnumerateSessions(
System.IntPtr hServer,
ref System.IntPtr ppSessionInfo,
ref int pCount)
{
WTSEnumerateSessions(hServer,0,1,ppSessionInfo,pCount);
}
VB Signature:
<DllImport("wtsapi32.dll", _
bestfitmapping:=True, _
CallingConvention:=CallingConvention.StdCall, _
CharSet:=CharSet.Auto, _
EntryPoint:="WTSEnumerateSessions", _
setlasterror:=True, _
ThrowOnUnmappableChar:=True)> _
Private Shared Function WTSEnumerateSessions( _
ByVal hServer As IntPtr, _
<MarshalAs(UnmanagedType.U4)> _
ByVal Reserved As Int32, _
<MarshalAs(UnmanagedType.U4)> _
ByVal Version As Int32, _
ByRef ppSessionInfo As IntPtr, _
<MarshalAs(UnmanagedType.U4)> _
ByRef pCount As Int32) As Int32
End Function
User-Defined Types:
Private Enum WTS_CONNECTSTATE_CLASS
WTSActive
WTSConnected
WTSConnectQuery
WTSShadow
WTSDisconnected
WTSIdle
WTSListen
WTSReset
WTSDown
WTSInit
End Enum
<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
Private Structure WTS_SESSION_INFO
Dim SessionID As Int32 'DWORD integer
Dim pWinStationName As String ' integer LPTSTR - Pointer to a null-terminated string containing the name of the WinStation for this session
Dim State As WTS_CONNECTSTATE_CLASS
End Structure
Notes:
None.
Tips & Tricks:
Please add some!
Sample Code:
Option Explicit On
Option Strict On
Imports System.Runtime.InteropServices
Public Class ManagedWTSAPI
Private Enum WTS_CONNECTSTATE_CLASS
WTSActive
WTSConnected
WTSConnectQuery
WTSShadow
WTSDisconnected
WTSIdle
WTSListen
WTSReset
WTSDown
WTSInit
End Enum
<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
Private Structure WTS_SESSION_INFO
Dim SessionID As Int32 'DWORD integer
Dim pWinStationName As String ' integer LPTSTR - Pointer to a null-terminated string containing the name of the WinStation for this session
Dim State As WTS_CONNECTSTATE_CLASS
End Structure
Friend Structure strSessionsInfo
Dim SessionID As Integer
Dim StationName As String
Dim ConnectionState As String
End Structure
<DllImport("wtsapi32.dll", _
bestfitmapping:=True, _
CallingConvention:=CallingConvention.StdCall, _
CharSet:=CharSet.Auto, _
EntryPoint:="WTSEnumerateSessions", _
setlasterror:=True, _
ThrowOnUnmappableChar:=True)> _
Private Shared Function WTSEnumerateSessions( _
ByVal hServer As IntPtr, _
<MarshalAs(UnmanagedType.U4)> _
ByVal Reserved As Int32, _
<MarshalAs(UnmanagedType.U4)> _
ByVal Vesrion As Int32, _
ByRef ppSessionInfo As IntPtr, _
<MarshalAs(UnmanagedType.U4)> _
ByRef pCount As Int32) As Int32
End Function
<DllImport("wtsapi32.dll")> _
Private Shared Sub WTSFreeMemory(ByVal pMemory As IntPtr)
End Sub
<DllImport("wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function WTSOpenServer(ByVal pServerName As String) As IntPtr
End Function
<DllImport("wtsapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Sub WTSCloseServer(ByVal hServer As IntPtr)
End Sub
Friend Function GetSessions(ByVal ServerName As String) As strSessionsInfo()
Dim ptrOpenedServer As IntPtr
Dim RetVal As strSessionsInfo()
Try
ptrOpenedServer = WTSOpenServer(ServerName)
Dim FRetVal As Int32
Dim ppSessionInfo As IntPtr = IntPtr.Zero
Dim Count As Int32 = 0
Try
FRetVal = WTSEnumerateSessions(ptrOpenedServer, 0, 1, ppSessionInfo, Count)
If FRetVal <> 0 Then
Dim sessionInfo() As WTS_SESSION_INFO = New WTS_SESSION_INFO(Count) {}
Dim i As Integer
For i = 0 To Count - 1 ' Step i + 1
sessionInfo(i) = CType(Marshal.PtrToStructure(ppSessionInfo, GetType(WTS_SESSION_INFO)), WTS_SESSION_INFO)
Next
WTSFreeMemory(ppSessionInfo)
Dim tmpArr(sessionInfo.GetUpperBound(0)) As strSessionsInfo
For i = 0 To tmpArr.GetUpperBound(0)
tmpArr(i).SessionID = sessionInfo(i).SessionID
tmpArr(i).StationName = sessionInfo(i).pWinStationName
tmpArr(i).ConnectionState = GetConnectionState(sessionInfo(i).State)
Next
ReDim sessionInfo(-1)
RetVal = tmpArr
Else
Throw New ApplicationException("No data retruned")
End If
Catch ex As Exception
Throw New Exception(ex.Message & vbCrLf & System.Runtime.InteropServices.Marshal.GetLastWin32Error)
End Try
Catch ex As Exception
Throw New Exception(ex.Message)
Exit Function
Finally
WTSCloseServer(ptrOpenedServer)
End Try
Return RetVal
End Function
Private Function GetConnectionState(ByVal State As WTS_CONNECTSTATE_CLASS) As String
Dim RetVal As String
Select Case State
Case WTS_CONNECTSTATE_CLASS.WTSActive
RetVal = "Active"
Case WTS_CONNECTSTATE_CLASS.WTSConnected
RetVal = "Connected"
Case WTS_CONNECTSTATE_CLASS.WTSConnectQuery
RetVal = "Query"
Case WTS_CONNECTSTATE_CLASS.WTSDisconnected
RetVal = "Disconnected"
Case WTS_CONNECTSTATE_CLASS.WTSDown
RetVal = "Down"
Case WTS_CONNECTSTATE_CLASS.WTSIdle
RetVal = "Idle"
Case WTS_CONNECTSTATE_CLASS.WTSInit
RetVal = "Initializing."
Case WTS_CONNECTSTATE_CLASS.WTSListen
RetVal = "Listen"
Case WTS_CONNECTSTATE_CLASS.WTSReset
RetVal = "reset"
Case WTS_CONNECTSTATE_CLASS.WTSShadow
RetVal = "Shadowing"
Case Else
RetVal = "Unknown connect state"
End Select
Return RetVal
End Function
End Class
Sample Code:
/// <summary>
///
/// Nice Wrapper Class To TS API
///
/// Darrell John Marjoram
/// darrell@no_spam_md2solutions.co.uk
///
/// 22 Feb 2005
///
/// </summary>
public class ManagedWTSAPI
{
[DllImport("wtsapi32.dll", CharSet=CharSet.Auto)]
private static extern bool WTSEnumerateSessions(
IntPtr hServer,
[MarshalAs(UnmanagedType.U4)]
int Reserved,
[MarshalAs(UnmanagedType.U4)]
int Version,
ref IntPtr ppSessionInfo,
[MarshalAs(UnmanagedType.U4)]
ref int pCount);
[DllImport("wtsapi32.dll")]
static extern int WTSFreeMemory(IntPtr pMemory);
[DllImport("wtsapi32.dll", CharSet=CharSet.Auto, SetLastError=true)]
static extern IntPtr WTSOpenServer(string pServerName);
[DllImport("wtsapi32.dll", CharSet=CharSet.Auto, SetLastError=true)]
static extern void WTSCloseServer(IntPtr hServer);
public enum WTS_CONNECTSTATE_CLASS
{
WTSActive,
WTSConnected,
WTSConnectQuery,
WTSShadow,
WTSDisconnected,
WTSIdle,
WTSListen,
WTSReset,
WTSDown,
WTSInit
}
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)]
private struct WTS_SESSION_INFO
{
public int SessionId;
public string pWinStationName;
public WTS_CONNECTSTATE_CLASS State;
}
public struct SessionsInfo
{
public int SessionId;
public string StationName;
public string ConnectionState;
}
private static string GetConnectionState(WTS_CONNECTSTATE_CLASS State)
{
string RetVal;
switch(State)
{
case WTS_CONNECTSTATE_CLASS.WTSActive:
RetVal = "Active";
break;
case WTS_CONNECTSTATE_CLASS.WTSConnected:
RetVal = "Connected";
break;
case WTS_CONNECTSTATE_CLASS.WTSConnectQuery:
RetVal = "Query";
break;
case WTS_CONNECTSTATE_CLASS.WTSDisconnected:
RetVal = "Disconnected";
break;
case WTS_CONNECTSTATE_CLASS.WTSDown:
RetVal = "Down";
break;
case WTS_CONNECTSTATE_CLASS.WTSIdle:
RetVal = "Idle";
break;
case WTS_CONNECTSTATE_CLASS.WTSInit:
RetVal = "Initialising";
break;
case WTS_CONNECTSTATE_CLASS.WTSListen:
RetVal = "Listen";
break;
case WTS_CONNECTSTATE_CLASS.WTSReset:
RetVal = "Reset";
break;
case WTS_CONNECTSTATE_CLASS.WTSShadow:
RetVal = "Shadowing";
break;
default:
RetVal = "Unknown connect state";
break;
}
return RetVal;
}
public static SessionsInfo[] GetSessions(string serverName)
{
IntPtr ptrOpenedServer = IntPtr.Zero;
SessionsInfo[] RetVal;
try
{
IntPtr buffer = IntPtr.Zero;
Int32 Count = 0;
ptrOpenedServer = WTSOpenServer(serverName);
try
{
if(WTSEnumerateSessions(ptrOpenedServer, 0, 1, ref buffer, ref Count))
{
// Marshal to a structure array here. Create the array first.
WTS_SESSION_INFO[] sessionInfo = new WTS_SESSION_INFO[Count];
int Size = Marshal.SizeOf(new WTS_SESSION_INFO());
// Cycle through and copy the array over.
for(int index = 0; index < Count; index++)
{
// Marshal the value over.
IntPtr CurIdxPtr = new IntPtr(buffer.ToInt64() + (Size * index));
sessionInfo[index] = (WTS_SESSION_INFO)Marshal.PtrToStructure(
CurIdxPtr, typeof(WTS_SESSION_INFO));
}
WTSFreeMemory(buffer);
SessionsInfo[] tmpArr = new SessionsInfo[sessionInfo.Length];
for(int i=0; i<tmpArr.Length; i++)
{
tmpArr[i].SessionId = sessionInfo[i].SessionId;
tmpArr[i].StationName = sessionInfo[i].pWinStationName;
tmpArr[i].ConnectionState = GetConnectionState(sessionInfo[i].State);
}
RetVal = tmpArr;
}
else
{
throw new ApplicationException("No data returned");
}
}
catch(Exception ex)
{
throw new Exception(ex.Message + "\r\n" + Marshal.GetLastWin32Error());
}
}
finally
{
if(ptrOpenedServer != IntPtr.Zero) WTSCloseServer(ptrOpenedServer);
}
return RetVal;
}
}
Alternative Managed API:
Do you know one? Please contribute it!
