vb6.0 转c#遇到问题，不解，惶惶不可终日，SOS求救大虾支援

[wo2007]

原来vb6.0代码

Declare Function OpenCom Lib "S7_200_PPI.dll" (ByVal ComNo As Long) As Long
Declare Function CloseCom Lib "S7_200_PPI.dll" () As Long
Declare Function SetBaudRate Lib "S7_200_PPI.dll" (ByVal BaudRate As Long) As Long
Declare Function bitsetV Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long, ByVal Vaddr As Long, ByVal bitNo As Long) As Long
Declare Function bitResetV Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long, ByVal Vaddr As Long, ByVal bitNo As Long) As Long
Declare Function bit Lib "S7_200_PPI.dll" (ByVal AByte As Byte, ByVal bitNo As Long) As Boolean
Declare Function readVB Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long, ByVal Vaddr As Long, ByVal length As Long, buff As Byte) As Long
Declare Function readVW Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long, ByVal Vaddr As Long, ByVal length As Long, buff As Integer) As Long
Declare Function writeVB Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long, ByVal Vaddr As Long, ByVal value As Byte) As Long
Declare Function writeVW Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long, ByVal Vaddr As Long, ByVal value As Integer) As Long
Declare Function PLCRUN Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long) As Long
Declare Function PLCSTOP Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long) As Long
Declare Sub setReadDelay Lib "S7_200_PPI.dll" (ByVal ADelayTime As Long)
Declare Sub setOKDelay Lib "S7_200_PPI.dll" (ByVal ADelayTime As Long)

    Dim rxdata(1024) As Integer
    Dim tmp As String
    Text1 = ""
    If readVW(2, Val(Text8), Val(Text10), rxdata(0)) > 0 Then
        tmp = ""
        For i = 0 To Val(Text10) - 1
            tmp = tmp & rxdata(i) & ","
        Next
        Text1 = tmp
    Else
        Text1 = "error"
    End If

我转为c#

public class Api
    {
        private Api()
        {
        }
         [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int OpenCom (Int32 ComNo);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int CloseCom ();

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int SetBaudRate (Int32 BaudRate);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int bitsetV (Int32 PLCaddr, Int32 Vaddr, Int32 bitNo);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int bitResetV (Int32 PLCaddr, Int32 Vaddr, Int32 bitNo);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int bit (byte AByte, Int32 bitNo);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int readVB (Int32 PLCaddr, Int32 Vaddr, Int32 length,Byte buff);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)]
        public static extern int readVW(Int32 PLCaddr, Int32 Vaddr, Int32 length, int buff);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int writeVB (Int32 PLCaddr, Int32 Vaddr, byte value);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int writeVW (Int32 PLCaddr, Int32 Vaddr, int value);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int PLCRUN (Int32 PLCaddr);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int PLCSTOP (Int32 PLCaddr);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)] 
        public static extern int setReadDelay (Int32 ADelayTime);

        [DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)]
        public static extern int setOKDelay(Int32 ADelayTime);

    }

//这句没问题
  if (Api.OpenCom(5) > 0){
                textBox1.Text = "打开成功";
            }
            else
            {
                textBox1.Text = "打开失败";
  }

//这个报错，由于是调用dll，无法捕获异常，竟然弹出APPCRASH问题（vb下没问题）……
           int[] rxdata = new int[1024];
            string tmp;
            textBox1.Text = "";
            if (Api.readVW(2, 40, 10, rxdata[0]) > 0)
            {
                tmp = "";
                for (int i = 0; i < 9; i++)
                {
                    tmp = tmp+rxdata[i].ToString()+",";
                }
            }
            else{
                tmp = "读取错误";

            }
            textBox1.Text =tmp;

调试N边无解，本来直接可以用vb做个后台程序算了，但不知问题何解，实在是纠结不堪、心神不定、如坐针毡、心烦意乱、胆战心惊、提心吊胆、寝食难安、惶惶不可终日、求救各位大虾出手了，在这里谢谢各位乡亲父老了……

[qbilbo]

声明：

[DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)]
public static extern int readVW(Int32 PLCaddr, Int32 Vaddr, Int32 length, IntPtr buff);

调用：

IntPtr p = Marshal.AllocHGlobal(1024);
if (Api.readVW(2, 40, 10, p) > 0)
{
        byte[] data = new byte[1024];
        Marshal.Copy(p, data, 0, 1024);
        ......
}

先这样试试。

[Poopaye]

Declare Function readVW Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long, ByVal Vaddr As Long, ByVal length As Long, buff As Integer) As Long

[DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)]
public static extern short readVW(Int32 PLCaddr, Int32 Vaddr, Int32 length, short[] buff);

我拿这个说明下吧 vb里long对应c#int / Int32 vb里integer对应c#short / Int16 像buff这个参数是byref，对应到c#里直接用数组就行

[以专业开发人员为伍]

vb6的程序可以编译为一个 COM 组件，然后你的 c# 项目引用这个 COM 组件即可。.net可以直接调用vb所产生的com组件，不用做什么参数类型转换，因此就跟用c#写的class一样方便。（当然，在部署时就要自动在用户机器上注册COM组件）。 否则，最好用c#重写你的vb6的程序。是用你的设备厂商提供的.net 组件，而不用 S7_200_PPI.dll。

[wo2007]

引用 1 楼 qbilbo 的回复:

声明：

[DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)]
public static extern int readVW(Int32 PLCaddr, Int32 Vaddr, Int32 length, IntPtr buff);

调用：

IntPtr p = Marshal.AllocHGlobal(1024);
if (Api.readVW(2, 40, 10, p) > 0)
{
        byte[] data = new byte[1024];
        Marshal.Copy(p, data, 0, 1024);
        ......
}

先这样试试。

托管内存这方法我不熟悉，我试了下，用foreach 取出data数据，第一组是对的，后面好像就不对了，不知道什么原因……谢了，已解决。

[wo2007]

引用 2 楼 shingoscar 的回复:

Declare Function readVW Lib "S7_200_PPI.dll" (ByVal PLCaddr As Long, ByVal Vaddr As Long, ByVal length As Long, buff As Integer) As Long

[DllImport("S7_200_PPI.dll", CallingConvention = CallingConvention.StdCall)]
public static extern short readVW(Int32 PLCaddr, Int32 Vaddr, Int32 length, short[] buff);

我拿这个说明下吧 vb里long对应c#int / Int32 vb里integer对应c#short / Int16 像buff这个参数是byref，对应到c#里直接用数组就行

我也是按照vb里long对应c#int / Int32，vb里integer对应c#short / Int16但没想到像buff这个参数是byref，对应到c#里直接用数组就行，原来是酱紫，我刚开始理解为从数组0依次写入，所以直接Api.readVW(2, 40, 10, rxdata[0])，谢谢，问题解决！

[wo2007]

引用 3 楼 sp1234 的回复:

vb6的程序可以编译为一个 COM 组件，然后你的 c# 项目引用这个 COM 组件即可。.net可以直接调用vb所产生的com组件，不用做什么参数类型转换，因此就跟用c#写的class一样方便。（当然，在部署时就要自动在用户机器上注册COM组件）。 否则，最好用c#重写你的vb6的程序。是用你的设备厂商提供的.net 组件，而不用 S7_200_PPI.dll。

哦，做成COM 组件也可以吗？到时试试，这是西门子的plc，百度了下，没有相关的厂商控件，通信协议也太费时间去折腾了，就找了个网上的dll文件用用，其实网络上dll文件的安全和稳定问题也是个麻烦事。