4

我有一个 WinForm 加载方法，它需要很长时间才能收集一些数据以显示给用户。

在执行此方法时，我会显示一个带有“Loading”字样的大字体表单。

但是，有时会出现此错误并且“加载”进度表没有关闭，然后最终我的整个应用程序将退出：

创建窗口句柄时出错。在 System.Windows.Forms.NativeWindow.CreateHandle（CreateParams cp）

当我在加载方法中执行代码时，有没有更好的方法来显示我的进度/加载表单？

这是我的代码：

//I launch a thread here so that way the Progress_form will display to the user
//while the Load method is still executing code.  I can not use .ShowDialog here
//or it will block.

//Progress_form displays the "Loading" form    
Thread t = new Thread(new ThreadStart(Progress_form));  

t.SetApartmentState(System.Threading.ApartmentState.STA);
t.IsBackground = true;
t.Start();

//This is where all the code is that gets the data from the database.  This could
//take upwards of 20+ seconds.

//Now I want to close the form because I am at the end of the Load Method                         

try
{
   //abort the Progress_form thread (close the form)
   t.Abort();
   //t.Interrupt();
}
catch (Exception)
{
}
4

3 回答 3

10

ABackgroundWorker是在不锁定 UI 线程的情况下执行长时间运行操作的好方法。

使用以下代码启动 BackgroundWorker 并显示加载表单。

// Configure a BackgroundWorker to perform your long running operation.
BackgroundWorker bg = new BackgroundWorker()
bg.DoWork += new DoWorkEventHandler(bg_DoWork);
bg.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bg_RunWorkerCompleted);

// Start the worker.
bg.RunWorkerAsync();

// Display the loading form.
loadingForm = new loadingForm();
loadingForm.ShowDialog();

这将导致在后台线程上执行以下方法。请注意，您不能从此线程操作 UI。尝试这样做将导致异常。

private void bg_DoWork(object sender, DoWorkEventArgs e)
{
    // Perform your long running operation here.
    // If you need to pass results on to the next
    // stage you can do so by assigning a value
    // to e.Result.
}

当长时间运行的操作完成时，该方法将在 UI 线程上调用。您现在可以安全地更新任何 UI 控件。在您的示例中，您可能希望关闭加载表单。

private void bg_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    // Retrieve the result pass from bg_DoWork() if any.
    // Note, you may need to cast it to the desired data type.
    object result = e.Result;

    // Close the loading form.
    loadingForm.Close();

    // Update any other UI controls that may need to be updated.
}
于 2013-04-02T18:19:45.310 回答
2

我已经在 .NET 4.0 上成功测试了这个。（WinForms）我有理由确定这将适用于 .NET 4.0+，并且应该是一个有用的代码片段，可以在大多数需要在进程结束时关闭表单的项目中重用。

private void SomeFormObject_Click(object sender, EventArgs e)
{
    myWait = new YourProgressForm();//YourProgressForm is a WinForm Object
    myProcess = new Thread(doStuffOnThread);
    myProcess.Start();
    myWait.ShowDialog(this);
}

private void doStuffOnThread()
{
    try
    {
        //....
        //What ever process you want to do here ....
        //....

        if (myWait.InvokeRequired) {
            myWait.BeginInvoke( (MethodInvoker) delegate() { closeWaitForm(); }  );
        }
        else
        {
            myWait.Close();//Fault tolerance this code should never be executed
        }
    }
    catch(Exception ex) {
        string exc = ex.Message;//Fault tolerance this code should never be executed
    }
}

private void closeWaitForm() {
    myWait.Close();
    MessageBox.Show("Your Process Is Complete");
}
于 2017-07-31T01:03:31.433 回答
1

我会将您在加载方法中的代码放入一个线程中。在表单的某处设置进度条，并在收集数据的代码的关键阶段增加它 - 但请注意不要在线程本身中执行此操作，即不要在单独的线程中篡改 ui 元素，您将需要使用委托来调用它们。

于 2013-04-02T16:34:36.537 回答