VB读取智能温湿度显示不变化
小弟学编了一个VB显示存储温湿度的程序，能读，也能写入ACCESS表中，每当温湿度计送过来信息时，能读进表中，但数值永远是第一次的，用串口助手读看出，每次送过来的是不一样的值。
附上程序请高手指点：

VB code

'串口模块Public Sub MyCom(MSComm1 As MSComm) On Error GoTo ErrHandle     With MSComm1  .CommPort = 3  '使用COM3 .Settings = "9600,N,8,1"                         '设置通信口参数  .InBufferSize = 60                      '设置MSComm1接收缓冲区为40字节  .OutBufferSize = 2                           '设置MSComm1发送缓冲区为2字节  .InputMode = comInputModeBinary                   '设置接收数据模式为文本式   .InputLen = 1                                  '设置Input 一次从接收缓冲读取字节数为1  .SThreshold = 1                                         '设置Output 一次从发送缓冲读取字节数为1  .RThreshold = 1     '接收缓冲区每收到一个，触发  .InBufferCount = 0                                      '清除接收缓冲区  .OutBufferCount = 0                                     '清除发送缓冲区    If .PortOpen = False Then          .PortOpen = True       End If   End With   Exit SubErrHandle:     MsgBox "通讯口打不开，请检查"    End Sub'这是向温度计发送读的命令Public Sub mySend(bytHex() As Byte)  ReDim bytHex(7) As Byte  ReDim bytHex(7)      bytHex(0) = &H1      bytHex(1) = &H4      bytHex(2) = &H0      bytHex(3) = &H0      bytHex(4) = &H0      bytHex(5) = &H2      bytHex(6) = &H71      bytHex(7) = &HFBEnd SubDim datatempA As Single  '这是采样温湿度值Dim datatempB As Single  '这是采样温湿度值Dim num As Integer   '这是采样温湿度个数Dim bytHex() As ByteDim InByte(1000) As Byte  '串口接收数据用Dim buffer As StringDim Varp As VariantPrivate Declare Sub Sleep Lib "Kernel32" (ByVal dwMilliseconds As Long)    '-----Sleep函数 延时函数'将收到的内容串联出来，因为COM口是接到一个触发一次Private Sub SwichVar(ByVal nNum As Integer)    Sleep (10)    Varp = Null    Varp = MSComm1.Input    InByte(nNum) = Varp(0)End SubPrivate Sub Form_Load()   '这是调用串口 MyCom MSComm1  '使时钟有效 Timer3.Enabled = TrueEnd SubPrivate Sub MSComm1_OnComm()   Dim datatemp1, datatemp2 As String   Call Sleep(50)    If MSComm1.CommEvent = 2 Then     MSComm1.RThreshold = 0     Dim i     For i = 1 To MSComm1.InBufferCount       SwichVar i       buffer = buffer & Right("00" & Hex(InByte(i)), 2) & Chr(32)     Next i      Text1.Text=buffer  '在这能看到接到的数据     datatemp1 = Mid(buffer, 10, 5)     datatempA = Val("&H" & datatemp1)     TempText.Text = (datatempA - 4000) / 100     datatemp2 = Mid(buffer, 16, 5)     datatempB = Val("&H" & datatemp2)     AverText.Text = datatempB / 100     Adodc3.ConnectionString = cnn.ConnectionString     Adodc3.RecordSource = "select * from Table_temp"     Adodc3.Refresh     If Adodc3.Recordset.RecordCount > 0 Then       Adodc3.Recordset.MoveLast     End If      cnn.Execute ("insert into Table_temp (温度值,湿度值)values('" & TempText & "','" & AverText & "')")                  MSComm1.RThreshold = 1   End IfEnd Sub

[解决办法]

如果你的温湿度数据是固定长度的，大可不必费那么多周章。

1 RThreshold = 12 '接收缓冲区收到12个触发，加入你的温湿度数据是 12 字节

2 可以去掉 Sleep 延时

3 直接读入数据：

Dim bytTmp() As Byte

bytTmp = MSComm1.Input

buffer = ""

For i = 0 To Ubound(bytTmp)

buffer = buffer & Right("00" & Hex(bytTmp(i)), 2) & Chr(32)

......

多说一句，你不用为串口开缓存，在 Driver 中已经有了。我们所谓的接收，只是等待 Driver 完成接收并从它的缓存中复制数据。