c# - 在表单加载时使用进度条

Question

我正在尝试用 C# 设计一个 WinForms 控件，它将在加载时从数据库中获取一些数据。

我想用进度条来显示进度。

我试过这段代码(还有许多其他代码):

protected override void OnLoad(EventArgs e)
{
    base.OnLoad(e);
    this.Show();
    
    progressBar1.Value = 10;
    int n;

    n = 50;//number of records in DB ,
    double progress = 0;
    double progstep = 25 / n;
    for (int i = 1; i <= n; i++)
    {
        //getting 
        if (progress <= 100)
            progressBar1.Value = (int)progress;
    }

    progressBar1.Value = 35;

    n = 100;//number of records in DB for another data reading from DB ,
    progress = 35;
    progstep = 65 / n;
    for (int i = 1; i <= n; i++)
    {
        //getting data from DB
        dataGridView1.Rows.Add(....);
        //Adding that data to a datagrid -- parametrs removed.
        progress += progress;
        if (progress <= 100)
            progressBar1.Value = (int)progress;
    }
}

但是，问题是表单会一直等到数据读取进度完成，而我只能看到完整的进度条和所有数据已加载。

我应该怎么做才能解决这个问题？

Answer 1

由于这是 winforms，我建议使用 BackgroundWorker .

基本示例:

bgWorker.DoWork += new DoWorkEventHandler(bgWorker_DoWork);
bgWorker.ProgressChanged += new DoWorkEventHandler(bgWorker_ProgressChanged);
bgWorker.RunWorkerAsync(//pass in object to process)

然后将启动:

private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
{
     //Do all of your work here
     bgWorker.ReportProgress(); //percent done calculation  
}

然后将触发 Progress changed 事件以安全地更新 UI:

private void bgWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
     progressBar.Value = e.ProgressPercentage;
}