第一种：使用BackgroundWorker进行进度条控制
BackgroundWorker对象有三个主要的事件：
DoWork - 当BackgroundWorker对象的多线程操作被执行时触发。
RunWokerCompleted - 当BackgroundWoker对象的多线程操作完成时触发。
ProgressChanged - 当BackgroundWorker对象的多线程操作状态改变时触发。
WorkerReportsProgress - 如果想让BackgroundWorker对象以异步的方式报告线程实时进度，必须将该属性的值设为true。
BackgroundWorker对象的ReportProgress方法用于向主线程返回后台线程执行的实时进度。

实例代码一，控制主窗体中的进度条显示

public partial class Form1 : Form
{
/// <summary>
/// 后台线程
/// </summary>
private BackgroundWorker bkWorker = new BackgroundWorker();

/// <summary>
/// 步进值
/// </summary>
private int percentValue = http://www.mamicode.com/0;

public Form1()
{
InitializeComponent();

bkWorker.WorkerReportsProgress = true;
bkWorker.WorkerSupportsCancellation = true;
bkWorker.DoWork += new DoWorkEventHandler(DoWork);
bkWorker.ProgressChanged += new ProgressChangedEventHandler(ProgessChanged);
bkWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(CompleteWork);
}

private void btnStart_Click(object sender, EventArgs e)
{
percentValue = http://www.mamicode.com/10;
this.progressBar1.Maximum = 1000;
// 执行后台操作
bkWorker.RunWorkerAsync();
}

public void DoWork(object sender, DoWorkEventArgs e)
{
// 事件处理，指定处理函数
e.Result = ProcessProgress(bkWorker, e);
}

public void ProgessChanged(object sender, ProgressChangedEventArgs e)
{
// bkWorker.ReportProgress 会调用到这里，此处可以进行自定义报告方式
this.progressBar1.Value = http://www.mamicode.com/e.ProgressPercentage;
int percent = (int)(e.ProgressPercentage / percentValue);
this.label1.Text = "处理进度:" + Convert.ToString(percent) + "%";
}

public void CompleteWork(object sender, RunWorkerCompletedEventArgs e)
{
this.label1.Text = "处理完毕!";
}

private int ProcessProgress(object sender, DoWorkEventArgs e)
{
for (int i = 0; i <= 1000; i++)
{
if (bkWorker.CancellationPending)
{
e.Cancel = true;
return -1;
}
else
{
// 状态报告
bkWorker.ReportProgress(i);

// 等待，用于UI刷新界面，很重要
System.Threading.Thread.Sleep(1);
}
}

return -1;
}
}

实例代码二，控制弹出窗体中的进度条显示
主窗体代码：

public partial class Form1 : Form
{
private BackgroundWorker bkWorker = new BackgroundWorker();
private Form2 notifyForm = new Form2();

public Form1()
{
InitializeComponent();

// 使用BackgroundWorker时不能在工作线程中访问UI线程部分，
// 即你不能在BackgroundWorker的事件和方法中操作UI，否则会抛跨线程操作无效的异常
// 添加下列语句可以避免异常。
CheckForIllegalCrossThreadCalls = false;

bkWorker.WorkerReportsProgress = true;
bkWorker.WorkerSupportsCancellation = true;
bkWorker.DoWork += new DoWorkEventHandler(DoWork);
bkWorker.ProgressChanged += new ProgressChangedEventHandler(ProgessChanged);
bkWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(CompleteWork);
}

private void btnStart_Click(object sender, EventArgs e)
{
notifyForm.StartPosition = FormStartPosition.CenterParent;

bkWorker.RunWorkerAsync();
notifyForm.ShowDialog();
}

public void DoWork(object sender, DoWorkEventArgs e)
{
// 事件处理，指定处理函数
e.Result = ProcessProgress(bkWorker, e);
}

public void ProgessChanged(object sender, ProgressChangedEventArgs e)
{
// bkWorker.ReportProgress 会调用到这里，此处可以进行自定义报告方式
notifyForm.SetNotifyInfo(e.ProgressPercentage, "处理进度:" + Convert.ToString(e.ProgressPercentage) + "%");
}

public void CompleteWork(object sender, RunWorkerCompletedEventArgs e)
{
notifyForm.Close();

MessageBox.Show("处理完毕!");
}

private int ProcessProgress(object sender, DoWorkEventArgs e)
{
for (int i = 0; i <= 1000; i++)
{
if (bkWorker.CancellationPending)
{
e.Cancel = true;
return -1;
}
else
{
// 状态报告
bkWorker.ReportProgress(i / 10);

// 等待，用于UI刷新界面，很重要
System.Threading.Thread.Sleep(1);
}
}

return -1;
}
}

子窗体代码:

public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}

public void SetNotifyInfo(int percent, string message)
{
this.label1.Text = message;
this.progressBar1.Value = http://www.mamicode.com/percent;
}
}

第二种，使用Thread来实现
使用Thread实现，虽然步骤上比较麻烦，但是调用流程比较简单，也是一种可以参考的方法
使用时，首先要定义代理以及函数，然后实现线程函数，在线程函数中调用代理，最后启动线程，传入线程函数。
下面是实例代码：

public partial class Form1 : Form
{
private Form2 progressForm = new Form2();
// 代理定义，可以在Invoke时传入相应的参数
private delegate void funHandle(int nValue);
private funHandle myHandle = null;

public Form1()
{
InitializeComponent();
}

private void btnStart_Click(object sender, EventArgs e)
{
// 启动线程
System.Threading.Thread thread = new System.Threading.Thread(new System.Threading.ThreadStart(ThreadFun));
thread.Start();
}

/// <summary>
/// 线程函数中调用的函数
/// </summary>
private void ShowProgressBar()
{
myHandle = new funHandle(progressForm.SetProgressValue);
progressForm.ShowDialog();
}

/// <summary>
/// 线程函数，用于处理调用
/// </summary>
private void ThreadFun()
{
MethodInvoker mi = new MethodInvoker(ShowProgressBar);
this.BeginInvoke(mi);

System.Threading.Thread.Sleep(1000); // sleep to show window

for (int i = 0; i < 1000; ++i)
{
System.Threading.Thread.Sleep(5);
// 这里直接调用代理
this.Invoke(this.myHandle, new object[] { (i / 10) });
}
}
}

子窗体代码

public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}

public void SetProgressValue(int value)
{
this.progressBar1.Value = http://www.mamicode.com/value;
this.label1.Text = "Progress :" + value.ToString() + "%";

// 这里关闭，比较好，呵呵！
if (value =http://www.mamicode.com/= this.progressBar1.Maximum - 1) this.Close();
}
}

C#调用耗时函数时显示进度条浅探