Question

大家帮我看看VB串行通信程序出什么问题了

我想把存在上位机已知数组a(i,j)中的数据发送给单片机。但是单片机的LED灯显示出数据没有正确发送过来（比如说我发生十进制的20，单片机没有正确接收到），我不知道错在哪里了，请大家帮我改正，或者给出正确的发送数据程序。如能成功，再追加50分。
Private Sub Command1_Click()
Dim a(i,j) As Long
Dim send As Variant
send = a(i,j)
MSComm1.Output = send
End Sub

Private Sub Form_Load()
Text1 = ""
Text2 = ""
MSComm1.CommPort = 1
MSComm1.Settings = "9600,n,8,1"
MSComm1.InBufferSize = 512
MSComm1.OutBufferSize = 512
MSComm1.RThreshold = 1
MSComm1.PortOpen = True
End Sub

Private Sub MSComm1_OnComm()
Dim a As String
Select Case MSComm1.CommEvent
Case 2
MSComm1.InputLen = 0
If MSComm1.InBufferCount Then
a= MSComm1.Input
Text2.Text = a
End If
End Select
End Sub

Answer 1

1、首先dim a(i,j) as long就错了，这里需要常数，如果你需要变量可以使用Redim语句
dim a() as long
i=2
j=2
Redim a(i,j) as long
2、MSComm1.Output 支持两种数据类型，一是字符串，二是Byte数组，所以MSComm1.Output = send也是错的。
dim send(0) as byte
send(0) = 20
MSComm1.Output = send
3、由于不知道你真正的意思，我试着写一段简单的程序，如有疑问可以百度HI我。
Private a(9, 9) As Byte
Private Sub Command1_Click() '#发送a()中某一个数据
Dim send(0) As Byte
i = Int(9 * Rnd)
j = Int(9 * Rnd)
send(0) = a(i, j)
MSComm1.Output = send
End Sub

Private Sub Form_Load()
'#初始化模拟数据
For i = 0 To 9
For j = 0 To 9
a(i, j) = i * j
Next
Next
Text2 = ""
'#Mscomm设置
MSComm1.InputMode = comInputModeBinary '#设置接收模式为二进制形式
MSComm1.CommPort = 3
MSComm1.Settings = "9600,n,8,1"
MSComm1.InBufferSize = 512
MSComm1.OutBufferSize = 512
MSComm1.RThreshold = 1
MSComm1.PortOpen = True
End Sub

Private Sub MSComm1_OnComm()
Dim RcvByte() As Byte
Dim strHex As String
strHex = ""
Select Case MSComm1.CommEvent
Case comEvReceive
MSComm1.InputLen = 0
If MSComm1.InBufferCount Then
RcvByte = MSComm1.Input '#获取接收的二进制数据
For i = LBound(RcvByte) To UBound(RcvByte)
strHex = strHex & Right("0" & CStr(Hex(RcvByte(i))), 2) & " " '#将二进制数据转换为文本显示到Text2
Next
Text2.Text = strHex
End If
End Select
End Sub

Answer 2

发送的是低字节在前，高字节在后。
Option Explicit
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)

Private Sub Command1_Click()
Dim a As Long
Dim Buffer(3) As Byte
a = Val(Text1)
CopyMemory Buffer(0), a, 4
MSComm1.Output = Buffer
End Sub

Private Sub Form_Load()
Text1 = ""
MSComm1.CommPort = 1
MSComm1.Settings = "9600,n,8,1"
MSComm1.InBufferSize = 512
MSComm1.OutBufferSize = 512
MSComm1.RThreshold = 1
MSComm1.PortOpen = True
End Sub

Answer 3

MSComm1.Output = send
这个用法是有问题的.
首先你要设置是按2进制发送数据还是字符串发送数据.
你要发送20 ,初始化设定MSComm1.InputMode = comInputModeBinary
dim bt(0) as byte '定义字节数组
bt(0)=a(ij)
MSComm1.Output = bt

如果要连续发送,可以这样
dim bt(3) as byte '发几个定义几个,然后赋值
bt(0)=..
bt(1)=..
bt(2)=..
bt(3)=..
MSComm1.Output = bt '一起发送

你试一下