wtsvirtualChannelread仅读取字符串的第一个字母
-
01-10-2019 - |
题
我正在尝试编写一个Hello World类型程序,用于在Windows终端服务客户端中使用虚拟渠道。
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
IntPtr mHandle = IntPtr.Zero;
private void Form1_Load(object sender, EventArgs e)
{
mHandle = NativeMethods.WTSVirtualChannelOpen(IntPtr.Zero, -1, "TSCRED");
if (mHandle == IntPtr.Zero)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
private void button1_Click(object sender, EventArgs e)
{
uint bufferSize = 1024;
StringBuilder buffer = new StringBuilder();
uint bytesRead;
NativeMethods.WTSVirtualChannelRead(mHandle, 0, buffer, bufferSize, out bytesRead);
if (bytesRead == 0)
{
MessageBox.Show("Got no Data");
}
else
{
MessageBox.Show("Got data: " + buffer.ToString());
}
}
protected override void Dispose(bool disposing)
{
if (mHandle != System.IntPtr.Zero)
{
NativeMethods.WTSVirtualChannelClose(mHandle);
}
base.Dispose(disposing);
}
}
internal static class NativeMethods
{
[DllImport("Wtsapi32.dll")]
public static extern IntPtr WTSVirtualChannelOpen(IntPtr server,
int sessionId, [MarshalAs(UnmanagedType.LPStr)] string virtualName);
//[DllImport("Wtsapi32.dll", SetLastError = true)]
//public static extern bool WTSVirtualChannelRead(IntPtr channelHandle, long timeout,
// byte[] buffer, int length, ref int bytesReaded);
[DllImport("Wtsapi32.dll")]
public static extern bool WTSVirtualChannelClose(IntPtr channelHandle);
[DllImport("Wtsapi32.dll", EntryPoint = "WTSVirtualChannelRead")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool WTSVirtualChannelRead(
[In()] System.IntPtr hChannelHandle
, uint TimeOut
, [Out()] [MarshalAs(UnmanagedType.LPStr)]
System.Text.StringBuilder Buffer
, uint BufferSize
, [Out()] out uint pBytesRead);
}
我正在从MSTSC COM对象和ActiveX Contront中发送数据。
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
rdp.Server = "schamberlainvm";
rdp.UserName = "TestAcct";
IMsTscNonScriptable secured = (IMsTscNonScriptable)rdp.GetOcx();
secured.ClearTextPassword = "asdf";
rdp.CreateVirtualChannels("TSCRED");
rdp.Connect();
}
private void button1_Click(object sender, EventArgs e)
{
rdp.SendOnVirtualChannel("TSCRED", "Hello World!");
}
}
//Designer code
//
// rdp
//
this.rdp.Enabled = true;
this.rdp.Location = new System.Drawing.Point(12, 12);
this.rdp.Name = "rdp";
this.rdp.OcxState = ((System.Windows.Forms.AxHost.State)(resources.GetObject("rdp.OcxState")));
this.rdp.Size = new System.Drawing.Size(1092, 580);
this.rdp.TabIndex = 0;
我每次都会执行 NativeMethods.WTSVirtualChannelRead
运行
对此的任何帮助将不胜感激。
编辑 - 函数运行时,mhandle具有非零值。更新代码以添加该检查。
edit2-我使用了 P/Indoke Interop助手 并产生了新的sigiture
[DllImport("Wtsapi32.dll", EntryPoint = "WTSVirtualChannelRead")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool WTSVirtualChannelRead(
[In()] System.IntPtr hChannelHandle
, uint TimeOut
, [Out()] [MarshalAs(UnmanagedType.LPStr)]
StringBuilder Buffer
, uint BufferSize
, [Out()] out uint pBytesRead);
现在,它收到文本字符串(是!),但仅获得我的测试字符串的第一个字母(boo!)。关于出了什么问题的想法?
编辑3 ---通话后应该阅读Hello World;
bytesread = 24
buffer.length = 1; buffer.capacity = 16; buffer.m_stringvalue =“ h”;
解决方案
问题是您要在发送侧发送16位Unicode字符串,并在另一个上读取ANSI字符串,因此编组层正在第一个NUL字符处终止字符串缓冲区。您可以更改 UnmanagedType.LPStr
到 UnmanagedType.LPWStr
或将其作为字节数组元帅,然后使用Unicode编码类转换为字符串。
这样的事情可能会起作用(注意:未经测试的代码,因为我没有服务器可以测试):
public static extern int WTSVirtualChannelRead(IntPtr hChannel,
uint Timeout,
[Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex=3)] byte[] Buffer,
uint BufferSize,
out uint BytesRead);
string DoRead(IntPtr hChannel)
{
byte[] buf = new byte[1024];
uint bytesRead;
if (WTSVirtualChannelRead(hChannel, 0, buf, (uint)buf.Length, out bytesRead) != 0)
{
return Encoding.Unicode.GetString(buf, 0, (int)bytesRead);
}
else
{
return "";
}
}
其他提示
我想写这篇文章后要洗个澡,但是...
private void button1_Click(object sender, EventArgs e)
{
uint bufferSize = 2;
StringBuilder buffer = new StringBuilder();
StringBuilder final = new StringBuilder();
uint bytesRead;
NativeMethods.WTSVirtualChannelRead(mHandle, 0, buffer, bufferSize, out bytesRead);
while (bytesRead != 0)
{
final.Append(buffer);
NativeMethods.WTSVirtualChannelRead(mHandle, 0, buffer, bufferSize, out bytesRead);
}
MessageBox.Show("Got data: " + final.ToString());
}
如果其他人可以为唯一一个传播问题提供更好的解决方案,我将很乐意接受而不是这样。
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