WinCE下VB.NET程序的开发

    Const WRITE_BASE_ADDRESS = &H0           ' 用于写入数据的基地址

    Const READ_BASE_ADDRESS = &H1000         ' 用于读取数据的基地址

Private Structure CMDINFO

      Dim pCMDBuf As UInteger         ' 指令缓冲区,应用申请空间,指针类型

       Dim dwWriteAddr As UInteger     ' 指令写入的地址

       Dim dwCMDLen As UInteger        ' 指令的长度

       Dim dwRetryCount As UInteger    ' 重试的次数

       Dim dwDelayTime As UInteger     ' 重试的周期,以ms为单位

End Structure

Private Structure READINFO
      Dim pReadBuf As UInteger         ' 读取数据的缓冲区,库申请空间,指针类型
      Dim dwDataAddr As UInteger       ' 读取RAM的地址
      Dim dwReadLen As UInteger        ' 读取数据的长度
      Dim dwRetryCount As UInteger     ' 重试的次数
      Dim dwDelayTime As UInteger      ' 重试的周期
  End Structure

    Private Declare Function SendCommand Lib "DPRAMLib" (ByVal CMDInfo As CMDINFO) As Integer

    Private Declare Function ReadDPRAM Lib "DPRAMLib" (ByRef ReadInfo As READINFO) As Integer

    Private Declare Sub WritePort Lib "DPRAMLib" (ByVal Port As UShort, ByVal Value As Byte)

    Private Declare Function ReadPort Lib "DPRAMLib" (ByVal Port As UShort) As Byte

Private Sub ButtonRead_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonRead.Click

        Dim i As Integer

        Dim szTmp As String

        Dim szShowBuf As String

        Dim ReadBuf As Byte()

        ' 获取地址

        RamAddr = Val("&H" + TextBoxAddr.Text.Substring(2))

        ' 获取长度

        Length = Val("&H" + TextBoxLength.Text.Substring(2))

        ' 调用库函数读取RAM

        stReadInfo.dwDelayTime = 2

        stReadInfo.dwRetryCount = 5

        stReadInfo.dwDataAddr = RamAddr     

        stReadInfo.dwReadLen = Length       

        stReadInfo.pReadBuf = vbNullString  

        ReadDPRAM(stReadInfo)

        Length = stReadInfo.dwReadLen - 1 ' 将长度转换为索引的最大值

        ' 获取读取出来的数据长度,并分配相应的内存

        ReDim ReadBuf(Length)

        ' 将库中读取的数据拷贝至托管代码的数组中,以便处理

        Marshal.Copy(stReadInfo.pReadBuf, ReadBuf, 0, stReadInfo.dwReadLen)

        ' 显示读取到的内容

        szShowBuf = "0000:"

        For i = 0 To Length Step 1

            szTmp = Hex(ReadBuf(i))

            If szTmp.Length = 1 Then

                szTmp = "0" & szTmp

            End If

            szShowBuf = szShowBuf & szTmp & " "

            If (i + 1) Mod (8) = 0 Then

                szShowBuf = szShowBuf & vbCrLf ' 加入换行符

                If i < Length Then

                    szTmp = Hex(i + 1)

                    Dim szTmp2 As New String("0", 4 - Len(szTmp))

                    szTmp = szTmp2 & szTmp & ":"

                    szShowBuf = szShowBuf & szTmp

                End If

            End If

        Next

        TextBoxValue.Text = szShowBuf

    End Sub

Private Sub ButtonWrite_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonWrite.Click

        Dim i As Integer, j As Integer, nLength As Integer

        Dim nValue As Byte

        Dim szTmp As String

        Dim WriteBuf As Byte()

        RamAddr = Val("&H" + TextBoxAddr.Text.Substring(2))

        ' 获取需要写入的数据

         nLength = TextBoxValue.Text.Length()

        ReDim WriteBuf((nLength + 1) / 3)

        i = 0

        j = 0

        While i < nLength

            szTmp = "&H" + Mid(TextBoxValue.Text, i + 1, 2)

            nValue = Val(szTmp)

            WriteBuf(j) = nValue

            i += 3

            j += 1

        End While

        Dim pt As New IntPtr

        pt = Marshal.AllocHGlobal(j)        ' 从进程的非托管内存中分配内存

         Marshal.Copy(WriteBuf, 0, pt, j)    ' 将数据从托管数组复制到非托管内存指针

        ' 调用库函数写入RAM

        stCmdInfo.pCMDBuf = pt

        stCmdInfo.dwCMDLen = j

        stCmdInfo.dwDelayTime = 2

        stCmdInfo.dwRetryCount = 5

        stCmdInfo.dwWriteAddr = RamAddr

        SendCommand(stCmdInfo)

        Marshal.FreeHGlobal(pt)   ' 释放使用AllocHGlobal 从进程的非托管内存中分配的内存

    End Sub