Question

使用Proficy Historian的c＃User API包装器，如何检索标签名称的所有（或过滤后的列表）？

我找到了方法ihuFetchTagCache，它填充缓存返回一个标签计数，但我找不到一种方法来访问这个缓存。

到目前为止我的代码：

string servername = "testServer";
int handle;
ihuErrorCode result;
result = IHUAPI.ihuConnect(servername, "", "", out handle);
if (result != ihuErrorCode.OK)
{//...}

int count;
result = IHUAPI.ihuFetchTagCache(handle, txtFilter.Text, out count);
if (result != ihuErrorCode.OK)
{//...}

如何阅读标签名称缓存？

Answer 1

使用4.5及更高版本中提供的新标记缓存方法实际上更好。以下是我使用的DLL导入定义。¹

[DllImport("ihuapi.dll", EntryPoint = "ihuCreateTagCacheContext@0")]
public static extern IntPtr CreateTagCacheContext();

[DllImport("ihuapi.dll", EntryPoint = "ihuCloseTagCacheEX2@4")]
public static extern ErrorCode CloseTagCacheEx2(IntPtr TagCacheContext);

[DllImport("ihuapi.dll", EntryPoint = "ihuFetchTagCacheEx2@16")]
public static extern ErrorCode FetchTagCacheEx2(IntPtr TagCacheContext, int ServerHandle, string TagMask, ref int NumTagsFound);

[DllImport("ihuapi.dll", EntryPoint = "ihuGetTagnameCacheIndexEx2@12")]
public static extern ErrorCode GetTagnameCacheIndexEx2(IntPtr TagCacheContext, string Tagname, ref int CacheIndex);

[DllImport("ihuapi.dll", EntryPoint = "ihuGetNumericTagPropertyByIndexEx2@16")]
public static extern ErrorCode GetNumericTagPropertyByIndexEx2(IntPtr TagCacheContext, int Index, TagProperty TagProperty, ref double Value);

[DllImport("ihuapi.dll", EntryPoint = "ihuGetStringTagPropertyByIndexEx2@20")]
public static extern ErrorCode GetStringTagPropertyByIndexEx2(IntPtr TagCacheContext, int Index, TagProperty TagProperty, StringBuilder Value, int ValueLength);

然后您可以使用以下代码。

IntPtr context = IntPtr.Zero;
try
{
    context = IHUAPI.CreateTagCacheContext();
    if (context != IntPtr.Zero)
    {
        int number = 0;
        ihuErrorCode result = IHUAPI.FetchTagCacheEx2(context, Connection.Handle, mask, ref number);
        if (result == ihuErrorCode.OK)
        {
            for (int i = 0; i < number; i++)
            {
                StringBuilder text = new StringBuilder();
                IHUAPI.GetStringTagPropertyByIndexEx2(context, i, ihuTagProperties.Tagname, text, 128);
                Console.WriteLine("Tagname=" + text.ToString());
            }
        }
    }
}
finally
{
    if (context != IntPtr.Zero)
    {
        IHUAPI.CloseTagCacheEx2(context);
    }
}

¹ 请注意，我不使用GE提供的DLL导入定义，因此我的代码可能看起来略有不同，但差异应该是微不足道的。

通过IHUAPI检索Proficy Historian标记名称

1 个答案: