我正在使用C＃和WinForms。我正在更新progressBar。当Value达到它的最大值时，我希望它显示一个messageBox。
无论如何，progressBar在它满了时执行一个方法吗？那么一些代码示例或解决方案的链接将不胜感激
private void BackgroundWorkerProgressChanged(object sender, ProgressChangedEventArgs e)
{
//throw new NotImplementedException();
}
private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
{
}
// Back on the 'UI' thread so we can update the progress bar - and our label :)
void bgWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
// The progress percentage is a property of e
int percentComplete = progressBarStatus.Value / progressBarStatus.Maximum;
labelPercentComplete.Text = percentComplete.ToString() + "% Completed";
//progressBarStatus.Value = e.ProgressPercentage;
//labelPercentComplete.Text = String.Format("Trade{0}", e.ProgressPercentage);
}
private void bgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if(progressBarStatus.Value == progressBarStatus.Maximum)
{
MessageBox.Show("Test");
}
}
public void Form1_Load(object sender, EventArgs e)
{
backgroundWorker1.DoWork += new DoWorkEventHandler(bgWorker_DoWork);
backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler
(bgWorker_RunWorkerCompleted);
backgroundWorker1.ProgressChanged += BackgroundWorkerProgressChanged;
}
答案 0 :(得分：3)
当后台工作程序完成时你似乎不想做某事，但是当进度条达到最大值时你想要做某事......好吧，首先，设置你的progressBarStatus最大值，然后你应该尝试这样的事情：
void bgWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
if (progressBarStatus.Maximum == e.ProgressPercentage)
{
// do whatever you want to do
}
}
并从另一个表单更新progressBarStatus值。 尽管这可能不是最好的做事方式，如果这真的是你想要的，那么做任何让你开心的事情...... :)
编辑： 好的，我添加了完美的程序的完整示例，调用ProgressChanged事件，并正确检查Maximum值，当达到Maximum值时，ProgressBar重新启动并在Output窗口中打印消息，评论（当然还有一堆错别字：D），请尝试这个例子，看看它是如何工作的，并将其应用到你的问题中。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Windows.Forms;
namespace BGWORKERAPP
{
public partial class Form1 : Form
{
BackgroundWorker bgWorker = new BackgroundWorker();
public Form1()
{
InitializeComponent();
bgWorker.DoWork += bw_DoWork;
bgWorker.WorkerReportsProgress = true; // needed to be able to report progress
bgWorker.WorkerSupportsCancellation = true; // needed to be able to stop the thread using CancelAsync();
bgWorker.ProgressChanged += bw_ProgressChanged;
bgWorker.RunWorkerCompleted += bw_RunWorkerCompleted;
// ProgressBar is added to the form manually, and here I am just setting some initial values
progressBarStatus.Maximum = 100;
progressBarStatus.Minimum = 0;
progressBarStatus.Value = 0;
progressBarStatus.Step = 10;
}
void bw_DoWork(object sender, DoWorkEventArgs e)
{
int i = 0;
while (true) // keep looping until user presses the "Stop" button
{
if (bgWorker.CancellationPending) // if bgWorker.CancelAsync() is called, this CancelationPending token will be set,
{ // and if statement will be true
bgWorker.CancelAsync();
return; // Thread is getting canceled, RunWorkerCompleted will be called next
}
i++; // add any value you want, I chose this value because of the test example...
Thread.Sleep(1); // give thread some time to report (1ms is enough for this example) - NECESSARY,
//WITHOUT THIS LINE, THE MAIN THREAD WILL BE BLOCKED!
bgWorker.ReportProgress(i); // report progress (will call bw_ProgressChanged) - NECESSARY TO REPORT PROGRESS!
}
}
int somethingTerrible = 1; // used to do something terrible ;)
void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
// I added this "somethingTerrible" variable to make the ProgressChanged run all over again, even when e.ProgressPercentage value
// is greater then the progressBarStatus.Maximum, but, you should call bw.CancelAsync() because the job should be finished.
// Also, this code will give you Exception eventually, numbers are limited after all...
if (somethingTerrible * progressBarStatus.Maximum == e.ProgressPercentage)
{
Debug.WriteLine("THIS IS CALLED WHEN THE MAXIMUM IS REACHED"); // this will be printed in the Output window
progressBarStatus.Value = 0; // progressBarStatus value is at the maximum, restart it (or Exception will be thrown)
//bw.CancelAsync(); // used to stop the thread when e.ProgressPercentage is equal to progressBarMaximum, but in our
// example, we just make the code keep running.
// We should cancel bgWorker now because the work is completed and e.ProgressPercentage will
// be greater then the value of the progressBarStatus.Maximum, but if you really want
// you can do something like this to make the thread keep reporting without any errors (until numbers reach the limit)...
somethingTerrible++;
}
else
{
progressBarStatus.Value++; // increasing progressBarStatus.Value, until we get to the maximum.
}
}
void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
MessageBox.Show("Worker completed"); // worker finished the task...
}
// Buttons are added to the Form manually as well
private void runBgTask_Click(object sender, EventArgs e) // button on the Form to start the thread
{
bgWorker.RunWorkerAsync(); // start the background worker (call DoWork)
}
private void stopBgTask_Click(object sender, EventArgs e) // button on the Form to stop the thread
{
bgWorker.CancelAsync(); // tell the background worker to stop (will NOT stop the thread immediately); the DoWork will be
// called once again, but with CancelationPending token set to true, so the if statement
// in the DoWork will be true and the thread will stop.
}
}
}
答案 1 :(得分：2)
我想你应该看看专门为此目的而制作的BackgroundWorker。完成工作后，您将获得Event RunWorkerCompleted。我给你一个工作的例子，你要复制很多文件。
BackgroundWorker bgWorker = new BackgroundWorker();
bgWorker.DoWork += BackgroundWorkerDoWork;
bgWorker.ProgressChanged += BackgroundWorkerProgressChanged;
bgWorker.RunWorkerCompleted += new BackgroundWorkerCompletedEventHandler
(bgWorker_RunWorkerCompleted);
void StartWork()
{
// Start BackGround Worker Thread
bgWorker.RunWorkerAsync();
}
void BackgroundWorkerDoWork(object sender, DoWorkEventArgs e)
{
//NOTE : DONT play with the UI thread here...
// Do Whatever work you are doing and for which you need to show progress bar
CopyLotsOfFiles() // This is the function which is being run in the background
e.Result = true;// Tell that you are done
}
void CopyLotsOfFiles()
{
Int32 counter = 0;
List<String> filestobeCopiedList = ...; // get List of files to be copied
foreach (var file in filestobeCopiedList)
{
counter++;
// Calculate percentage for Progress Bar
Int32 percentage = (counter * 100) / filesCount;
bgWorker.ReportProgress(percentage);
// Files copy code goes here
}
bgWorker.ReportProgress(100);
}
void BackgroundWorkerProgressChanged(object sender, ProgressChangedEventArgs e)
{
// Access Main UI Thread here
progressBar1.Value = e.ProgressPercentage;
}
private void BackgroundWorkerCompletedEventHandler(object sender, RunWorkerCompletedEventArgs e)
{
//Always check e.Cancelled and e.Error before checking e.Result!
//even though I'm skipping that here
var operationSuccessFul = Convert.ToBoolean(e.Result);
if(operationSuccessFul)
MessageBox.Show("I am Done");
}
完成后，您将在BackgroundWorkerCompletedEventHandler函数中进行调用。您应该在BackgroundWorkerProgressChanged事件处理程序
中显示进度条答案 2 :(得分：1)
你应该反思：创建一个中心＆＃34; Progress类＆＃34;。本课程负责：
或者换句话说：它不是进度条的响应性......除了显示进度之外还做其他事情。