C# 线程与ArcGIS

我刚刚偶然发现了Backgroundworker对象，它似乎是我正在寻找的工具，用于在执行计算时使GUI响应。我正在为ArcGIS编写IO插件

public class Program
{
    private volatile bool AbortOperation;
    Func<bool> AbortOperationDelegate;
    FinishProcessDelegate finishDelegate;
    UpdateGUIDelegate updateGUIDelegate;

    private delegate void UpdateGUIDelegate(int progress, object message);
    private delegate void FinishProcessDelegate();

    private void cmdBegin_Click(...)
    {
        // Create finish delegate, for determining when the thread is done.
        finishDelegate = new FinishProcessDelegate(ProcessFinished);
        // A delegate for updating the GUI.
        updateGUIDelegate = new UpdateGUIDelegate(UpdateGUI);
        // Create a delegate function for abortion.
        AbortOperationDelegate = () => AbortOperation;

        Thread BackgroundThread = new Thread(new ThreadStart(StartProcess));            
        // Force single apartment state. Required by ArcGIS.
        BackgroundThread.SetApartmentState(ApartmentState.STA);
        BackgroundThread.Start();
    }

    private void StartProcess()
    {    
        // Update GUI.
        updateGUIDelegate(0, "Beginning process...");

        // Create object.
        Converter converter = new Converter(AbortOperationDelegate);
        // Parse the GUI update method to the converter, so it can update the GUI from within the converter. 
        converter.Progress += new ProcessEventHandler(UpdateGUI);
        // Begin converting.
        converter.Execute();

        // Tell the main thread, that the process has finished.
        FinishProcessDelegate finishDelegate = new FinishProcessDelegate(ProcessFinished);
        Invoke(finishDelegate);

        // Update GUI.
        updateGUIDelegate(100, "Process has finished.");
    }

    private void cmdAbort_Click(...)
    {
        AbortOperation = true;
    }

    private void ProcessFinished()
    {
        // Post processing.
    }

    private void UpdateGUI(int progress, object message)
    {
        // If the call has been placed at the local thread, call it on the main thread.
        if (this.pgStatus.InvokeRequired)
        {
            UpdateGUIDelegate guidelegate = new UpdateGUIDelegate(UpdateGUI);
            this.Invoke(guidelegate, new object[] { progress, message });
        }
        else
        {
            // The call was made on the main thread, update the GUI.
            pgStatus.Value = progress;
            lblStatus.Text = (string)message;   
        }
    }
}

public class Converter
{
    private Func<bool> AbortOperation { get; set;}

    public Converter(Func<bool> abortOperation)
    {
        AbortOperation = abortOperation;
    }

    public void Execute()
    {
        // Calculations using ArcGIS are done here.
        while(...) // Insert your own criteria here.
        {
            // Update GUI, and replace the '...' with the progress.
            OnProgressChange(new ProgressEventArgs(..., "Still working..."));

            // Check for abortion at anytime here...
            if(AbortOperation)
            {
                return;
            }
        }
    }

    public event ProgressEventHandler Progress;
    private virtual void OnProgressChange(ProgressEventArgs e)
    {
        var p = Progress;
        if (p != null)
        {
            // Invoke the delegate. 
        p(e.Progress, e.Message);
        }
    }    
}

public class ProgressEventArgs : EventArgs
{
    public int Progress { get; set; }
    public string Message { get; set; }
    public ProgressEventArgs(int _progress, string _message)
    {
        Progress = _progress;
        Message = _message;
    }
}

public delegate void ProgressEventHandler(int percentProgress, object userState);

我在ArcGIS之外做一些数据处理，使用backgroundworker可以很好地工作。但当我将数据插入ArcGIS时，backgroundworker似乎将持续时间增加了9倍左右。将处理代码置于DoWork方法之外，可将性能提高9倍

我在网上读过好几个地方，但是我没有多线程编程的经验，像STA和MTA这样的术语对我来说毫无意义。 我还尝试使用一个简单的线程实现，但结果类似

有人知道我能做些什么来使用ArcGIS处理和维护响应性GUI吗

编辑：我已经包括了一个与后台工作人员互动的示例。如果我将StartImporting方法中的代码放在cmdStart\u Click方法中，它的执行速度会快得多

private void StartImporting(object sender, DoWorkEventArgs e)
{
    DateTime BeginTime = DateTime.Now;
    // Create a new report object.
    SKLoggingObject loggingObject = new SKLoggingObject("log.txt");
    loggingObject.Start("Testing.");

    SKImport skImporter = new SKImport(loggingObject);
    try
    {
        // Read from a text box - no writing.
    skImporter.Open(txtInputFile.Text);
    }
    catch
    {
    }
    SKGeometryCollection convertedCollection = null;

    // Create a converter object.
    GEN_SK2ArcGIS converter = new GEN_SK2ArcGIS(loggingObject);

    // Convert the data.
    convertedCollection = converter.Convert(skImporter.GetGeometry());

    // Create a new exporter.
    ArcGISExport arcgisExporter = new ArcGISExport(loggingObject);

    // Open the file.            
    // Read from a text box - no writing.
    arcgisExporter.Open(txtOutputFile.Text);

    // Insert the geometry collection.
    try
    {
    arcgisExporter.Insert(convertedCollection);
    }
    catch
    {
    }
    TimeSpan totalTime = DateTime.Now - BeginTime;
    lblStatus.Text = "Done...";

}

private void ChangeProgress(object sender, ProgressChangedEventArgs e) 
{
    // If any message was passed, display it.
    if (e.UserState != null && !((string)e.UserState).Equals(""))
    {
    lblStatus.Text = (string)e.UserState;
    }
    // Update the progress bar.
    pgStatus.Value = e.ProgressPercentage;
}

private void ImportDone(object sender, RunWorkerCompletedEventArgs e)
{
    // If the process was cancelled, note this.
    if (e.Cancelled)
    {
    pgStatus.Value = 0;
    lblStatus.Text = "Operation was aborted by user...";
    }
    else
    {
    }

}

private void cmdStart_Click(object sender, EventArgs e)
{
    // Begin importing the sk file to the geometry collection.

    // Initialise worker.
    bgWorker = new BackgroundWorker();
    bgWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(ImportDone);
    bgWorker.ProgressChanged += new ProgressChangedEventHandler(ChangeProgress);
    bgWorker.DoWork += new DoWorkEventHandler(StartImporting);
    bgWorker.WorkerReportsProgress = true;
    bgWorker.WorkerSupportsCancellation = true;

    // Start worker.
    bgWorker.RunWorkerAsync();

}

private void cmdCancel_Click(object sender, EventArgs e)
{
    bgWorker.CancelAsync();
}

---

您好，Casper

为了维护响应良好的GUI，您通常需要在不同的线程中执行代码。通过使用BeginInvoke方法使用.net，这非常容易：

---

简而言之，将所有非GUI代码包含在一个单独的类（或多个类）中，而不是直接调用每个方法，而是创建一个委托并在该委托上调用BeginInvoke方法。然后，该方法将关闭并执行它的操作，而无需与GUI进一步交互。如果您希望它更新GUI（例如进度条），那么您可以从类中引发事件并从GUI中捕获它们，但是您需要确保以线程安全的方式更新控件。如果您希望在方法完成时更新GUI，那么您可以使用EndInvoke方法来处理该问题，通常是为了维护响应性GUI，您需要在不同的线程中执行执行工作的代码。通过使用BeginInvoke方法使用.net，这非常容易：

---

简而言之，将所有非GUI代码包含在一个单独的类（或多个类）中，而不是直接调用每个方法，而是创建一个委托并在该委托上调用BeginInvoke方法。然后，该方法将关闭并执行它的操作，而无需与GUI进一步交互。如果您希望它更新GUI（例如进度条），那么您可以从类中引发事件并从GUI中捕获它们，但是您需要确保以线程安全的方式更新控件。如果您希望在方法完成时更新GUI，那么可以使用EndInvoke方法来处理该问题，我一直在尝试找到解决方案，下面是我最后要做的。代码是从不同的文件中剪切和粘贴的，并呈现给大家，让大家了解我所做的工作。它演示了如何调用使用线程与ArcGIS通信的方法。代码允许我在主线程中更新GUI，中止操作，并执行操作后的操作。我最终使用了我最初发布的链接中的第一个线程部分

最初性能损失的原因可能是由于ArcGIS所需的单线程单元（STA）。Backgroundworker似乎是MTA，因此不适合使用ArcGIS

好了，我希望我没有忘记任何事情，并且可以自由编辑我的解决方案。这将有助于我和其他人为ArcGIS开发东西

public class Program
{
    private volatile bool AbortOperation;
    Func<bool> AbortOperationDelegate;
    FinishProcessDelegate finishDelegate;
    UpdateGUIDelegate updateGUIDelegate;

    private delegate void UpdateGUIDelegate(int progress, object message);
    private delegate void FinishProcessDelegate();

    private void cmdBegin_Click(...)
    {
        // Create finish delegate, for determining when the thread is done.
        finishDelegate = new FinishProcessDelegate(ProcessFinished);
        // A delegate for updating the GUI.
        updateGUIDelegate = new UpdateGUIDelegate(UpdateGUI);
        // Create a delegate function for abortion.
        AbortOperationDelegate = () => AbortOperation;

        Thread BackgroundThread = new Thread(new ThreadStart(StartProcess));            
        // Force single apartment state. Required by ArcGIS.
        BackgroundThread.SetApartmentState(ApartmentState.STA);
        BackgroundThread.Start();
    }

    private void StartProcess()
    {    
        // Update GUI.
        updateGUIDelegate(0, "Beginning process...");

        // Create object.
        Converter converter = new Converter(AbortOperationDelegate);
        // Parse the GUI update method to the converter, so it can update the GUI from within the converter. 
        converter.Progress += new ProcessEventHandler(UpdateGUI);
        // Begin converting.
        converter.Execute();

        // Tell the main thread, that the process has finished.
        FinishProcessDelegate finishDelegate = new FinishProcessDelegate(ProcessFinished);
        Invoke(finishDelegate);

        // Update GUI.
        updateGUIDelegate(100, "Process has finished.");
    }

    private void cmdAbort_Click(...)
    {
        AbortOperation = true;
    }

    private void ProcessFinished()
    {
        // Post processing.
    }

    private void UpdateGUI(int progress, object message)
    {
        // If the call has been placed at the local thread, call it on the main thread.
        if (this.pgStatus.InvokeRequired)
        {
            UpdateGUIDelegate guidelegate = new UpdateGUIDelegate(UpdateGUI);
            this.Invoke(guidelegate, new object[] { progress, message });
        }
        else
        {
            // The call was made on the main thread, update the GUI.
            pgStatus.Value = progress;
            lblStatus.Text = (string)message;   
        }
    }
}

public class Converter
{
    private Func<bool> AbortOperation { get; set;}

    public Converter(Func<bool> abortOperation)
    {
        AbortOperation = abortOperation;
    }

    public void Execute()
    {
        // Calculations using ArcGIS are done here.
        while(...) // Insert your own criteria here.
        {
            // Update GUI, and replace the '...' with the progress.
            OnProgressChange(new ProgressEventArgs(..., "Still working..."));

            // Check for abortion at anytime here...
            if(AbortOperation)
            {
                return;
            }
        }
    }

    public event ProgressEventHandler Progress;
    private virtual void OnProgressChange(ProgressEventArgs e)
    {
        var p = Progress;
        if (p != null)
        {
            // Invoke the delegate. 
        p(e.Progress, e.Message);
        }
    }    
}

public class ProgressEventArgs : EventArgs
{
    public int Progress { get; set; }
    public string Message { get; set; }
    public ProgressEventArgs(int _progress, string _message)
    {
        Progress = _progress;
        Message = _message;
    }
}

public delegate void ProgressEventHandler(int percentProgress, object userState);

公共类程序
{
私人易变业务；
函数中止操作委托；
FinishProcessDelegate finishDelegate；
UpdateGUIDelegate UpdateGUIDelegate；
私有委托void UpdateGUIDelegate（int进程，对象消息）；
私有委托void FinishProcessDelegate（）；
私有void cmdBegin\u单击（…）
{
//创建完成委托，用于确定线程何时完成。
finishDelegate=新的FinishProcessDelegate（ProcessFinished）；
//用于更新GUI的委托。
updateGUIDelegate=新的updateGUIDelegate（UpdateGUI）；
//创建用于中止的委托函数。
AbortOperationDelegate=（）=>AbortOperation；
线程背景线程=新线程（新线程开始（StartProcess））；
//强制单间公寓状态。ArcGIS要求。
BackgroundThread.SetApartmentState（ApartmentState.STA）；
BackgroundThread.Start（）；
}
私有void StartProcess（）
{    
//更新GUI。
updateGUIDelegate（0，“正在开始进程…”）；
//创建对象。
转换器=新转换器（中止操作委托）；
//将GUI更新方法解析到转换器，以便它可以从转换器内更新GUI。
converter.Progress+=新的ProcessEventHandler（UpdateGUI）；
//开始转换。
converter.Execute（）；
//告诉主线程进程已经完成。
FinishProcessDelegate finishDelegate=新的FinishProcessDelegate（ProcessFinished）；
调用（finishDelegate）；
//更新GUI。
updateGUIDelegate（100，“进程已完成”）；
}
私有void cmdAbort_单击（…）
{
中止操作=真；
}
私有void ProcessFinished（）
{
//后处理。
}
私有void UpdateGUI（int进程，对象消息）
{
//如果调用已放在本地线程上，则在主线程上调用它。
if（this.pgStatus.invokererequired）
{
UpdateGUIDelegate guidelegate=新的UpdateGUIDelegate（UpdateGUI）；
调用（guidelegate，新对象[]{progress，message}）；
}
其他的
{
//调用是在主线程上进行的，更新GUI。
pgStatus.Value=进度；
lblStatus.Text=（字符串）消息；
}
}
}
公众的
protected virtual void StatusUpdateNotify(ProgressState progressState)
{
    if (BackgroundWorker.CancellationPending)
    {
        throw new OperationCanceledException();
    }

    BackgroundWorker.ReportProgress(progressState.Progress, progressState);
}