WTclient创建OPC client方法

1.按照上一篇日志“ OPC客户端设计 ”的方法安装动态链接库及相关的注册工作。

2.包含头文件：

　　opcda.h

　　opc_ae.h

　　WTclientAPI.h

3.添加库文件：

　　WTclient.lib (要被加入解决方案)

　　WTclient.dll

4.初始化方法：

　　WTclientCoInit();

　　CoUninitialize();

5.查询所有的OPC server：

　　//得到OPC server个数
    int serverNumber = NumberOfOPCServers(TRUE, "");

    //得到所有OPC server的名字
    char buf[100];
    CString serverName;
    for(int i=0; i < serverNumber; i++)
    {
        GetOPCServerName (i, buf, 100);
        serverName = buf;
        MessageBox(0, serverName, 0);
    }

6.建立OPC连接：

ConnectionHandle = ConnectOPC ("", serverName, FALSE);

7.断开OPC连接：

DisconnectOPC(ConnectionHandle);
ConnectionHandle = INVALID_HANDLE_VALUE;

8.添加组：

CString groupName = "groupName";
    DWORD Rate = 100;
    float DeadBand = 100;
    HANDLE    hGroup = AddOPCGroup (ConnectionHandle, groupName, &Rate, &DeadBand);

    if (hGroup == INVALID_HANDLE_VALUE)
    {
        MessageBox("Error in adding group.", "警告", 0);
        return;
    }

9.删除组：

void  RemoveOPCGroup (HANDLE hConnect, HANDLE hGroup);

10.添加项目：

CString itemName = "itemName";
HANDLE itemHandle = AddOPCItem(ConnectionHandle, hGroup, itemName);

11.移除项目：

void  RemoveOPCItem (HANDLE hConnect, HANDLE hGroup, HANDLE hItem);

12.读取项目：

//读取项目
VARIANT *pVar = new VARIANT;
FILETIME *pTimeStamp = new FILETIME;
DWORD *pQuality = new DWORD;
ReadOPCItem (ConnectionHandle, hGroup, itemHandle, pVar, pTimeStamp, pQuality);

13.写入项目

VARIANT newVar;
newVar.dblVal = 3.141592;

WriteOPCItem (ConnectionHandle, hGroup, itemHandle, &newVar, 1);

我的完整示例：

//初始化
    WTclientCoInit();

    //得到OPC server个数
    int serverNumber = NumberOfOPCServers(TRUE, "");

    //得到所有OPC server的名字
    char buf[100];
    CString serverName;
    vector<CString> serverNames;

    for(int i=0; i < serverNumber; i++)
    {
        GetOPCServerName (i, buf, 100);
        serverName = buf;
        serverNames.push_back(serverName);
    }

    if(serverNumber == 0)
    {
        MessageBox("没有可用的OPC服务器", "警告", 0);
        return ;
    }

    //建立OPC连接
    ConnectionHandle = ConnectOPC ("", serverNames[0], TRUE);

    if (ConnectionHandle == INVALID_HANDLE_VALUE)
    {
        MessageBox("Error in connecting.", "警告", 0);
        return;
    }

    //得到项目个数
    int itemNum = NumberOfOPCItems(ConnectionHandle);

    //得到所有项目名称
    char itemBuf[128];
    CString iName;
    vector<CString> itemNames;
    for(int index = 0; index < itemNum; index++)
    {
        if(GetOPCItemName (ConnectionHandle, index, itemBuf, 128))
        {
            iName = itemBuf;
            itemNames.push_back(iName);
        }
        else
        {
            MessageBox("读取item名失败", "警告", 0);
            return ;
        }

    }

    //得到所有项目属性
    for(vector<CString>::iterator iter = itemNames.begin(); iter != itemNames.end(); ++iter)
    {
        //得到当前项目的属性个数
        int propNum = NumberOfItemProperties(ConnectionHandle, *iter);

        for(int i = 0; i < propNum; i++)
        {
            //得到属性特征
            DWORD propertyID = 0;
            VARTYPE vt;
            BYTE describtion[1024];
            GetItemPropertyDescription (ConnectionHandle, i, &propertyID, &vt, describtion, 1024);

            //读取当前属性值
            VARIANT value;
            ReadPropertyValue (ConnectionHandle, *iter, propertyID, &value);
        }
    }

    //添加组
    CString groupName = "groupName";
    DWORD Rate = 1;
    float DeadBand = 1;
    HANDLE    hGroup = AddOPCGroup (ConnectionHandle, groupName, &Rate, &DeadBand);

    if (hGroup == INVALID_HANDLE_VALUE)
    {
        MessageBox("Error in adding group.", "警告", 0);
        return;
    }

    //添加项目
    CString itemName = "Bucket Brigade.Boolean";
    HANDLE itemHandle = AddOPCItem(ConnectionHandle, hGroup, itemName);

    if (itemHandle == INVALID_HANDLE_VALUE)
    {
        MessageBox("该项不存在.", "警告", 0);
        return;
    }

    //得到项目类型
    VARTYPE type;
    DWORD AccessRights;
    GetOPCItemType(ConnectionHandle, hGroup, "Bucket Brigade.Boolean", &type,  &AccessRights);



    //读取项目
    VARIANT *pVar = new VARIANT;
    FILETIME *pTimeStamp = new FILETIME;
    DWORD *pQuality = new DWORD;
    if( !ReadOPCItem (ConnectionHandle, hGroup, itemHandle, pVar, pTimeStamp, pQuality))
    {
        MessageBox("读取失败.", "警告", 0);
        return ;
    }


    //写入项目
    VARIANT newVar;
    newVar.vt = 4;
    newVar.fltVal = 3.14;
    if(!WriteOPCItem (ConnectionHandle, hGroup, itemHandle, &newVar, 1))
    {
        MessageBox("写入失败.", "警告", 0);
        return ;
    }


    //读取项目
    ReadOPCItem (ConnectionHandle, hGroup, itemHandle, pVar, pTimeStamp, pQuality);