原创 串口枚举vb6.0

    作MCU项目时，经常用到串口UART通讯，把PC的RS232通过逻辑转换以后和MCU的UART相联。常会用VB、VC等编写一些小工具，VC偶学了很长的时候，但是没学会，没办法继续用丢人的VB。用vb编写串口通讯程序比较简单，使用控件MSCOM或者API都可以，使用COM以前会枚举PC上所有的COM，物理COM和虚拟的COM。对于windows XP系统串口映射在注册表 HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM里面，如图1。

图1 注册表中的SERIALCOM项

    枚举所有的串口只需要读取注册表的这个子项就可一个了。可以调用读取Register的API完成。下面几个函数可能被用到。

RegCloseKey

RegEnumValue

RegOpenKeyEx

RegOpenKey
RegQueryValue
RegQueryValueEx

实例，新建图二所示的form

图2 COM口枚举实例

添加如下代码：

Option Explicit

Private Declare Function RegCloseKey Lib _
    "advapi32.dll" (ByVal hKey As Long) As Long

Private Declare Function RegEnumValue Lib _
    "advapi32.dll" Alias "RegEnumValueA" _
    (ByVal hKey As Long, _
    ByVal dwIndex As Long, _
    ByVal lpValueName As String, _
    lpcbValueName As Long, _
    ByVal lpReserved As Long, _
    lpType As Long, _
    lpData As Byte, _
    lpcbData As Long) As Long

Private Declare Function RegOpenKeyEx Lib "advapi32.dll" Alias "RegOpenKeyExA" _
    (ByVal hKey As Long, _
    ByVal lpSubKey As String, _
    ByVal ulOptions As Long, _
    ByVal samDesired As Long, _
    phkResult As Long) As Long
Private Declare Function RegOpenKey Lib "advapi32.dll" Alias "RegOpenKeyA" _
    (ByVal hKey As Long, _
    ByVal lpSubKey As String, _
    phkResult As Long) As Long
Const HKEY_LOCAL_MACHINE = &H80000002
Const REG_SZ = 1
Private Declare Function RegQueryValue Lib "advapi32.dll" Alias "RegQueryValueA" _
    (ByVal hKey As Long, _
    ByVal lpSubKey As String, _
    ByVal lpValue As String, _
    lpcbValue As Long) As Long
Private Declare Function RegQueryValueEx Lib "advapi32.dll" Alias "RegQueryValueExA" _
    (ByVal hKey As Long, _
    ByVal lpValueName As String, _
    ByVal lpReserved As Long, _
    lpType As Long, _
    lpData As Any, _
    lpcbData As Long) As Long         ' Note that if you declare the lpData parameter as String, you must pass it By Value.

Private Sub Command1_Click()
End
End Sub

Private Sub Command2_Click()
On Error GoTo err
If Me.Combo1.Text <> "" Then
    Dim s As String
    s = Trim$(Me.Combo1.Text)
    s = Right(s, Len(s) - 3)
    Comport = CLng(s)
    'frmIRdemo.Show
    frmpc2lm.Show
    Unload Me
End If
Exit Sub
err:
MsgBox err.Description
End Sub

Private Sub Form_Load()
Dim hKey As Long
Dim cnt As Long
Dim strkm As String
Dim strkv As String
Dim lenData As Long, typeData As Long
Me.Combo1.Text = ""
RegOpenKey HKEY_LOCAL_MACHINE, "Hardware\DeviceMap\SerialComm", hKey
strkm = String(255, Chr(0))
Do While RegEnumValue(hKey, cnt, strkm, 255, 0, ByVal 0&, ByVal 0&, ByVal 0&) = 0
    'Debug.Print strkm
    If RegQueryValueEx(hKey, strkm, 0, typeData, ByVal vbNullString, lenData) = 0 Then
        strkv = String(lenData, Chr(0))
        RegQueryValueEx hKey, strkm, 0, typeData, ByVal strkv, lenData
        'Debug.Print strkv
        If strkv <> "" Then Me.Combo1.AddItem Trim$(strkv)
    End If
    cnt = cnt + 1
Loop
Me.Combo1.ListIndex = 0
End Sub

运行情况如下：

图3 运行情况