Winforms中的后台工作程序加载屏幕 [英] Background Worker loading screen in Winforms

问题描述

我有一个可以登录的表单，可能需要一段时间才能将数据加载到表单中.因此，我想在加载表单时使用进度条创建一个单独的表单(loadScreen.cs).我在loadScreen.cs表单中尝试过此操作:

I have a Form where one can Sign In and it could take a while till the data gets loaded into the Form. So I wanted to create a seperate Form (loadScreen.cs) with a Progress Bar when the Form is loading. I tried this in the loadScreen.cs Form:

 private void Form1_Load(object sender, EventArgs e)
 {
   worker = new BackgroundWorker();
   worker.WorkerReportsProgress = true;
   worker.WorkerSupportsCancellation = true;

   worker.DoWork += new DoWorkEventHandler(worker_DoWork);
   worker.ProgressChanged +=
          new ProgressChangedEventHandler(worker_ProgressChanged);
   worker.RunWorkerCompleted +=
         new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
 }



 void worker_DoWork(object sender, DoWorkEventArgs e)
 {
   int percentFinished = (int)e.Argument;
   while (!worker.CancellationPending && percentFinished < 100)
 {
   percentFinished++;
   worker.ReportProgress(percentFinished);
   System.Threading.Thread.Sleep(50);
 }
 e.Result = percentFinished;
 }


 void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
 {
   progressBar1.Value = e.ProgressPercentage;
 }


 void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
 {
  this.Close();
  }

我已阅读到worker_DoWork方法应具有需要花费较长时间加载的代码.我不知道该如何处理，因为我的按钮位于Form1中.单击它后，我将与

I've read that the worker_DoWork method should have the code which takes longer to load. I don't know how to handle this since my button is in Form1. When it's clicked then I go to another class with

  private void signIn_Click(object sender, EventArgs e)
    {
        var logIn = new LogIn(this);
        logIn.checkUserInput(this);
    }

然后执行加载某些内容的操作.如何连接一切?我需要帮助！

and there I execute the operations which load certain things. How to connect everything? I need help!

推荐答案

我实际上正在为这种事情创建通用对话.还没有及时准备好对您有用，但是我建议您遵循类似的思路.创建正在加载"对话框，以便它接受委托并在DoWork事件处理程序中调用它.然后，主窗体可以包含执行该工作的方法，并且您可以将该方法的委托传递给对话框.我将发布一个非常基本的示例.

I'm actually in the process of creating a general-purpose dialogue for this sort of thing. It's not going to be ready in time to be of use to you but I would suggest that you go along similar lines. Create your "Loading" dialogue so that it accepts a delegate and invokes it in the DoWork event handler. The main form can then contain a method that does the work and you can pass a delegate for that method to the dialogue. I'll post a very basic example.

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private DataTable table;

    private void button1_Click(object sender, EventArgs e)
    {
        var work = new Action(GetData);

        using (var f2 = new Form2(work))
        {
            f2.ShowDialog();
            this.dataGridView1.DataSource = this.table;
        }
    }

    private void GetData()
    {
        this.table = new DataTable();

        using (var adapter = new SqlDataAdapter("SELECT * FROM MyTable", "connectionstring here"))
        {
            adapter.Fill(table);
        }
    }
}


public partial class Form2 : Form
{
    private Action work;

    public Form2(Action work)
    {
        InitializeComponent();

        this.work = work;
    }

    private void Form2_Load(object sender, EventArgs e)
    {
        this.backgroundWorker1.RunWorkerAsync();
    }

    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        this.work();
    }

    private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        this.DialogResult = DialogResult.OK;
    }
}

请注意，使用数据适配器时没有真正的方法来衡量进度，因此在这种情况下，您只能真正显示选取框进度条.

Note that there's no real way to measure progress when using a data adapter so you could only really display a marquee progress bar in this case.

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