枫芸志

【WPF】C#跨线程操作窗体控件

为防止任务处理对界面操作的阻塞，用多线程进行处理是自然对用到的方法，不过也引入了跨线程操作的问题。今天碰到的问题是任务线程需要获取和设置窗体控件的属性，解决还是蛮容易的，引入delegate即可解决。

写了一个实例程序，效果是文本框txtOutput中实时显示文本框txtUsername和密码框txtPassword的内容，代码如下：





using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Threading;

namespace WPF
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        /// <summary>
        /// 监控线程
        /// </summary>
        private Thread mThread = null;

        /// <summary>
        /// 获取控件文本内容的线程代理
        /// </summary>
        /// <param name="control">Control</param>
        /// <returns>string</returns>
        private delegate string GetTextHandle(Control control);

        /// <summary>
        /// 获取控件文本内容
        /// </summary>
        /// <param name="control">Control</param>
        /// <returns>string</returns>
        private string GetText(Control control)
        {
            if (this.Dispatcher.Thread != System.Threading.Thread.CurrentThread)
            {
                return (string)this.Dispatcher.Invoke(new GetTextHandle(this.GetText), control);
            }
            else
            {
                if (control.GetType() == typeof(TextBox))
                {
                    return ((TextBox)control).Text;
                }
                else if (control.GetType() == typeof(PasswordBox))
                {
                    return ((PasswordBox)control).Password;
                }
                else
                {
                    return string.Empty;
                }
            }
        }

        /// <summary>
        /// 显示文本的线程代理
        /// </summary>
        /// <param name="text">string</param>
        private delegate void ShowTextHandle(string text);

        /// <summary>
        /// 显示文本
        /// </summary>
        /// <param name="text">string</param>
        private void ShowText(string text)
        {
            if (this.Dispatcher.Thread != System.Threading.Thread.CurrentThread)
            {
                this.Dispatcher.Invoke(new ShowTextHandle(this.ShowText), text);
            }
            else
            {
                this.txtOutput.Text = text;
            }
        }

        /// <summary>
        /// 监控输入并实时显示
        /// </summary>
        private void MonitorInput()
        {
            while (true)
            {
                string username = this.GetText(txtUsername);
                string password = this.GetText(txtPassword);
                string output = String.Format("Username:{0}, Password:{1}", username, password);
                this.ShowText(output);
            }
        }

        /// <summary>
        /// 窗口内容渲染好时启动监控线程
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Window_ContentRendered(object sender, EventArgs e)
        {
            mThread = new Thread(MonitorInput);
            mThread.Start();
        }

        /// <summary>
        /// 窗口关闭时结束线程
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Window_Closed(object sender, EventArgs e)
        {
            mThread.Abort();
        }
    }
}

列几个C#多线程相关的参考资料：

1. 正确使用异步操作
2. 第一期总结之三：Thread的问题
3. .Net多线程总结(一) 
4. .Net多线程总结(二)-BackgroundWorker
5. .Net线程问题解答



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标签： CSharp
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