在表单加载上使用进度条

对不起，我的英语不好

我正在尝试在C＃中设计一个Win Form，它将在加载时从数据库中获取一些数据

我想使用进度条显示阅读数据进度

我试过这个代码（以及其他许多代码）

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，Form将等待，直到数据读取进度完成，我只能看到一个完整的进度条和所有加载的数据。

我该怎么做才能解决这个问题？

谢谢

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) 

然后开始：

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

然后，Progress change事件将触发安全地更新UI：

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

Answer 2

这是一个简单的模型，向您展示如何使用backround worker：

首先在OnLoad创建后台工作者并向其附加2个事件：

 var bw = new BackgroundWorker(); bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(WorkCompleted); bw.DoWork += new DoWorkEventHandler(DoWork); bw.RunWorkerAsync(data); //assume data is list of numbers private void WorkCompleted(object sender, RunWorkerCompletedEventArgs e) //after work completed remove event handlers and dispose { var bw = (BackgroundWorker)sender; bw.RunWorkerCompleted -= WorkCompleted; bw.DoWork -= DoWork; bw.Dispose(); } private void DoWork(object sender, DoWorkEventArgs e) { var data = (List)e.Argument; foreach (var number in data) { if (progressBar1.InvokeRequired) { progressBar1.Invoke((MethodInvoker)delegate { this.ProcessNumber(number); }); } else { ProcessNumber(number); } } } private void ProcessNumber(int i) { progressBar1.PerformStep(); //do something with i } 

Answer 3

将backgroundWorker1添加到表单中。

然后添加YourForm_Shown事件

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

在InitializeComponent()之后添加表单的构造函数

  backgroundWorker1.WorkerReportsProgress = true; // This event will be raised on the worker thread when the worker starts backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork); // This event will be raised when we call ReportProgress backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged); 

最后添加backgroundWorker1的空白

  void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e) { // The progress percentage is a property of e progressBar1.Value = e.ProgressPercentage; } 

和

  void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) { for (int i = 1; i <= n; i++) { //getting data from DB dataGridView1.Rows.Add(....);//Adding that data to a datagrid -- parametrs removed. backgroundWorker1.ReportProgress(i); // Simulate long task } } 

Answer 4

看看BackgroundWorker控件。 在表单加载调用期间

 backgroundWorker.RunWorkerAsync(); 

并覆盖事件DoWork以执行脏工作（从db加载数据）和ProgressChanged以更新进度条。 在事件正文中（假设事件签名将是这样的）：

  private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e) { var worker = (BackgroundWorker)sender; // time consuming operation worker.ReportProgress(10, null); // ... another stuff } private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e) { progressBar.Value = e.ProgressPercentage; }