vb.net 指定IP端口是否开放

using System.Net;

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if(!string.IsNullOrEmpty(txtPort.Text))

{

IPAddress ip = IPAddress.Parse(txtIp.Text);

IPEndPoint point=new IPEndPoint(ip,int.Parse(txtPort.Text));

try

{

TcpClient tcp=new TcpClient();

tcp.Connect(point);

MessageBox.Show("端口打开");

}catch(Exception ex)

{

MessageBox.Show(ex.Message);

}

}

通过以上这个方法，只能判断你是否能链接这个端口。

通过以下这个方法，能判断端口是否开放

public static void GetTcpConnections() 

{ 

IPGlobalProperties properties = IPGlobalProperties.GetIPGlobalProperties(); 

TcpConnectionInformation[] connections = properties.GetActiveTcpConnections(); 

string str="";

foreach (TcpConnectionInformation t in connections) 

{ 

str+="Local endpoint:"+ t.LocalEndPoint.ToString()+","; 

str+="Remote endpoint:"+ t.RemoteEndPoint.ToString()+","; 

str+=t.State.ToString()+","; 

} 

MessageBox.Show(str);

}

怎样在vb中自动检测到可用串口号的具体程序代码

vb.net的话

For

Each

sp

As

String

In

My.Computer.Ports.SerialPortNames

cbxport.Items.Add(sp)

Next

vb6.0的话要调用API查看串口相关信息存在的注册表。

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM

通过读注册表的方法获得串口数量，当然也可以获得串口号了。

Option

Explicit

Private

Declare

Function

RegOpenKey

Lib

"advapi32.dll

"

Alias

"RegOpenKeyA

"

(ByVal

hKey

As

Long,

ByVal

lpSubKey

As

String,

phkResult

As

Long)

As

Long

Private

Declare

Function

RegQueryInfoKey

Lib

"advapi32.dll

"

Alias

"RegQueryInfoKeyA

"

(ByVal

hKey

As

Long,

ByVal

lpClass

As

String,

lpcbClass

As

Long,

ByVal

lpReserved

As

Long,

lpcSubKeys

As

Long,

lpcbMaxSubKeyLen

As

Long,

lpcbMaxClassLen

As

Long,

lpcValues

As

Long,

lpcbMaxValueNameLen

As

Long,

lpcbMaxValueLen

As

Long,

lpcbSecurityDescriptor

As

Long,

lpftLastWriteTime

As

Long)

As

Long

Private

Const

HKEY_LOCAL_MACHINE

=

H80000002

'

获得当前系统的

COM

口的数量

Function

GetCOMCount()

As

Integer

Dim

ret

As

Long,

cntCOM

As

Long

RegOpenKey

HKEY_LOCAL_MACHINE,

"HARDWARE\DEVICEMAP\SERIALCOMM

",

ret

RegQueryInfoKey

ret,

"

",

0,

0,

0,

0,

0,

cntCOM,

0,

0,

0,

GetCOMCount

=

cntCOM

End

Function

Private

Sub

Command1_Click()

MsgBox

"您的机器有

"

GetCOMCount

"

个串口。

",

vbOKOnly,

"串口数量

"

End

Sub

怎样用VB来判断串口是否存在,是否被占用？是否有数据输入？

如下是检测串口是否存在,是否被占用的代码:

Option Explicit

Dim a As Integer

Private Sub Form_Load()

MSComm1.Settings = "9600,n,8,1"

MSComm1.InputMode = comInputModeBinary '采用二进制传输

MSComm1.InBufferCount = 0 '清空接受缓冲区

MSComm1.OutBufferCount = 0 '清空传输缓冲区

MSComm1.RThreshold = 1 '产生MSComm事件

MSComm1.InBufferSize = 1024

Shape1.FillStyle = 0

OpenPortNum

End Sub

Private Sub OpenPortNum()

On Error GoTo uerror

For a = 1 To 16

MSComm1.CommPort = a

MSComm1.PortOpen = True

If MSComm1.PortOpen = True Then

Print "可用Com号= "; a

MSComm1.PortOpen = False

End If

Next

Exit Sub

uerror:

Print "出错或占用Com号= "; a

Resume Next

End Sub

如要探测某个COM口是否有数据输入则需在打开某个串口后,用OnComm事件来接收.

VB.Net中怎么获取打印机端口名称

打印机端口查看方法如下：

1、进入“控制面板”-“设备和打印机”；

2、右键需要查看的打印机，选择“属性”；

3、选择”Web服务“，即可查看IP端口。

当前题目：vb.net端口检测 端口 检测
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