我有一个继承自 Queue 类的自定义 Queue 类。它有一个事件 ItemAdded。在此事件的事件处理程序中,我正在执行一个方法。但它正在主线程之外运行,尽管我希望它在主线程中。我不知道该怎么做。有什么建议吗?
//My custom class
using System;
using System.Collections; //Required to inherit non-generic Queue class.
namespace QueueWithEvent
{
public class SmartQueue:Queue
{
public delegate void ItemAddedEventHandler(object sender, EventArgs e);
public event ItemAddedEventHandler ItemAdded;
protected virtual void OnItemAdded(EventArgs e)
{
if (ItemAdded != null)
{
ItemAdded(this, e);
}
}
public override void Enqueue(object Item)
{
base.Enqueue(Item);
OnItemAdded(EventArgs.Empty);
}
}
}
//Winform application
using System;
using System.ComponentModel;
using System.Windows.Forms;
using QueueWithEvent;
namespace TestApp
{
public partial class Form1 : Form
{
SmartQueue qTest = new SmartQueue();
public Form1()
{
InitializeComponent();
qTest.ItemAdded += new SmartQueue.ItemAddedEventHandler(this.QChanged);
}
private void btnStartBgw_Click(object sender, EventArgs e)
{
DisplayThreadName();
bgwTest.RunWorkerAsync();
}
private void bgwTest_DoWork(object sender, DoWorkEventArgs e)
{
try
{
for (int i = 0; i < 11; i++)
{
string valueTExt = i.ToString();
qTest.Enqueue(valueTExt);
System.Threading.Thread.Sleep(5000);
}
}
catch (Exception Ex)
{
MessageBox.Show(Ex.Message);
}
}
private void DisplayThreadName()
{
string tName = System.Threading.Thread.CurrentThread.ManagedThreadId.ToString();
txtThreadName.Text = tName;
}
private void QChanged(object sender, EventArgs e)
{
//#########I want this method to run on main thread #############
DisplayThreadName();
}
}
}
提前致谢。
SK保罗.
您正在后台线程上对项目进行排队(DoWork 事件处理程序在后台线程上运行),因此您的事件也在后台线程中引发。
Use InvokeRequired
方法来验证您是否在 UI 线程上。如果没有,则使用Invoke
在 UI 线程上运行代码:
private void QChanged(object sender, EventArgs e)
{
if (InvokeRequired)
{
Invoke((MethodInvoker)delegate { QChanged(sender, e); });
return;
}
// this code will run on main (UI) thread
DisplayThreadName();
}
您的另一个选择 - 使用ProgressChanged
将项目排队的事件(不要忘记设置WorkerReportsProgress
为真)。该事件处理程序在 UI 线程上运行:
private void bgwTest_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = (BackgroundWorker)sender;
for (int i = 0; i < 11; i++)
{
// use user state for passing data
// which is not reflecting progress percentage
worker.ReportProgress(0, i);
System.Threading.Thread.Sleep(5000);
}
}
private void bgwTest_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
string valueTExt = e.UserState.ToString();
qTest.Enqueue(valueTExt);
}
本文内容由网友自发贡献,版权归原作者所有,本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容,请联系:hwhale#tublm.com(使用前将#替换为@)