如果在C＃应用程序中的线程上执行，则SCardControl的速度会降低5倍

如何解决如果在C＃应用程序中的线程上执行，则SCardControl的速度会降低5倍

我正在使用Visual Studio 2019构建一个C＃Win Form应用程序，该应用程序旨在与SmartCard（ACR 122U）通信。

简而言之：我正在使用的标签类型是被动标签，读者无法识别。使用这些标签的唯一方法是将直接命令发送到读取器内部的芯片。

我使用winscard.dll设法做到了。

我正在尝试备份标签：该过程必须读取和存储128个块（因此将调用128个SCardControl）。

如果我在UI线程中执行此操作，它的工作原理就像一个魅力（最长5秒，过程中该过程占用30MB的内存）。 但是，如果我尝试在后台线程中执行此操作，则将花费很多时间（至少25秒，在此过程中需要150MB的内存用于该过程）。

为什么会这样？

编辑：

这是线程的一些代码

//All the DllImport directives:
[DllImport("winscard.dll")]
public static extern int SCardEstablishContext(uint dwScope,IntPtr notUsed1,IntPtr notUsed2,out IntPtr phContext);

[DllImport("winscard.dll",EntryPoint = "SCardListReadersA",CharSet = CharSet.Ansi)]
public static extern int SCardListReaders(IntPtr hContext,byte[] mszGroups,byte[] mszReaders,ref UInt32 pcchReaders);

//... Other working method delcarations

//Declaration of the "slow" method SCardControl
[DllImport("winscard.dll")]
public static extern int SCardControl(IntPtr hCard,int dwControlCode,byte[] lpInBuffer,uint cbInBufferSize,byte[] lpOutBuffer,ref uint cbOutBufferSize,ref int lpBytesReturned);

//... Other declarations.

private void btnBackup_Click(object sender,EventArgs e)
{
    Thread t = new Thread(bgWorker);
    t.Start();
    //bgWorker();
}

public void bgWorker() {
    int res;
    
    uint SystemScope = 2; //From the documentation. Tried both 1 and 2 (User scope and System Scope)
    uint readerNum = 0;
    uint controlMode = 3; //Using SCARD_SHARE_DIRECT as control mode in order to communicate with the reader
    uint protocolToUse = 0; //Using SCARD_PROTOCOL_UNDEFINED as protocol (must use it in order to use SCARD_SHARE_DIRECT)
    int EscapeCode = 3225264; //Suggested by ACR 122 U: Escape code in order to send commands to the reader,computes as SCARD_CTL_CODE(3500) in C.
    string ReadBlockCmd = "FF000000..." //Standard read command in hex for the tag from dtatasheet
    
    IntPtr context = IntPtr.Zero;
    IntPtr simulatedCard = IntPtr.Zero;
    IntPtr protocolEstablished = IntPtr.Zero;

    byte[] readerStream;
    string[] readerList;
    byte[] retStream = new byte[1000];
    uint sizeRetStream = 0;
    int sizeResponse = 0;

    List<string> cardBlocks = new List<string>();

    //NOTE: "res" is always = 0 when everything works. I cutted off the parts where i check the value of "res".

    //Establishing context
    res = SCardEstablishContext(SystemScope,IntPtr.Zero,out context);

    //Getting the reader list (the return is in "readerStream",with a multistring value)
    res = SCardListReaders(context,null,ref readerNum);
    readerStream = new byte[readerNum];
    res = SCardListReaders(context,readerStream,ref readerNum);
    readerList = Encoding.ASCII.GetString(readerStream).Split('\0');

    //Connect to the reader
    res = SCardConnect(context,readerList[0],controlMode,protocolToUse,ref simulatedCard,ref protocolEstablished);
    
    /* 
     * Some calls to SCardControl to configure the reader in order to work with my tags
     */
     
    //Backup procedure
    for(int i = 0; i < 128; i++)
    {
        SCardControl(simulatedCard,EscapeCode,HexStrToByteArray(ReadBlockCmd + i.ToString("X2")),(uint)ReadBlockCmd.Length / 2 + 1,retStream,ref sizeRetStream,ref sizeResponse);
        cardBlocks.Add(ByteArrayToHexStr(retStream,sizeResponse));
    }

    //Here it supposed to do the backup on file,but i removed it in order to limit the IO ops
}

如果注释线程启动部分并取消注释对bgWorker（）的调用，则过程将持续2.1秒。 如果保持这种状态（使用线程），则该过程将持续20秒钟以上（无论是在调试模式下，在发行版中，在Visual Studio中还是在外部）。