关于ProgressBar控件使用的问题

Question

我想使用ProgressBar控件来显示对一个数组的初始化进度，编写了如下代码：

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim a(1000, 1000) As String
        Dim I, J As Integer
        ProgressBar1.Maximum = 1001
        ProgressBar1.Minimum = 0
        ProgressBar1.Value = 0          
        For I = 0 To 1000
            For J = 0 To 1000
                a(I, J) = "*****"
            Next J
            ProgressBar1.Increment(1)    
        Next I
        MsgBox("初始化完毕")
    End Sub

期望数组初始化完毕，进度条填充到最右侧，然后显示消息框。可是为什么执行时，进度条还没填充完毕就开始显示消息框了呢。感觉MSGBOX提前出现了。

Answer 1

用BackgroundWorker控件

DoWork 初始化、ProgressChanged 显示进度、 RunWorkerCompleted显示消息框

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Answer 2

谢谢，对BackgroundWorker控件不甚了解，看了一下帮助，大概编写的一个，不成啊，能否给个详细的？

Answer 3

谢谢，对BackgroundWorker控件不甚了解，看了一下帮助，大概编写的一个，不成啊，能否给个详细的？

你的代码？

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http://feiyun0112.cnblogs.com/

Answer 4

谢谢，对BackgroundWorker控件不甚了解，看了一下帮助，大概编写的一个，不成啊，能否给个详细的？

简单来说，处理Do_Work事件等；同时调用RunAsync()……

具体参考来自MSDN的示例代码：http://msdn.microsoft.com/en-us/library/system.componentmodel.backgroundworker.aspx

using System;
using System.ComponentModel;
using System.Windows.Forms;

namespace BackgroundWorkerSimple
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            backgroundWorker1.WorkerReportsProgress = true;
            backgroundWorker1.WorkerSupportsCancellation = true;
        }

        private void startAsyncButton_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.IsBusy != true)
            {
                // Start the asynchronous operation.
                backgroundWorker1.RunWorkerAsync();
            }
        }

        private void cancelAsyncButton_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.WorkerSupportsCancellation == true)
            {
                // Cancel the asynchronous operation.
                backgroundWorker1.CancelAsync();
            }
        }

        // This event handler is where the time-consuming work is done. 
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = sender as BackgroundWorker;

            for (int i = 1; i <= 10; i++)
            {
                if (worker.CancellationPending == true)
                {
                    e.Cancel = true;
                    break;
                }
                else
                {
                    // Perform a time consuming operation and report progress.
                    System.Threading.Thread.Sleep(500);
                    worker.ReportProgress(i * 10);
                }
            }
        }

        // This event handler updates the progress. 
        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            resultLabel.Text = (e.ProgressPercentage.ToString() + "%");
        }

        // This event handler deals with the results of the background operation. 
        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled == true)
            {
                resultLabel.Text = "Canceled!";
            }
            else if (e.Error != null)
            {
                resultLabel.Text = "Error: " + e.Error.Message;
            }
            else
            {
                resultLabel.Text = "Done!";
            }
        }
    }
}

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Answer 5

我在界面上放了一个Progressbar控件，设置其Maximum为1000000，另外还有一个命令按钮Button1和一个BackgroundWorker控件，代码如下，但是没效果，不懂了，帮忙看看，谢谢。

Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        BackgroundWorker1.RunWorkerAsync()
    End Sub

    Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
        Dim a(1000, 1000) As String
        Dim I, J As Integer
        For I = 0 To 1000
            For J = 0 To 1000
                a(I, J) = "*****"
            Next J
        Next I
    End Sub

    Private Sub BackgroundWorker1_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
        ProgressBar1.Increment(1)
    End Sub

    Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
        MsgBox("初始化完毕")
    End Sub
End Class

Answer 6

 Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
        Dim a(1000, 1000) As String
        Dim I, J As Integer
        For I = 0 To 1000
            For J = 0 To 1000
                                a(I, J) = "*****"
BackgroundWorker1.ReportProgress(1)  '触发此事件，不要忘记把BackgroundWorker设置成WorkerReportsProgress=true.
            Next J
        Next I
    End Sub

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我的博客园
慈善点击，点击此处