C# 多線程窗體的創建

　　從目前已經在項目中工作將近一個月來的情況來看，凡是費時的操作，基本上都要用到多線程的等待窗體、進度提示窗體等實時顯示動態的進度信息。而如果直接在主線程的窗體上實時更新信息，就會造成更新太快或者太慢而出現的進程假死現象。為了緩解這些情況，本文就參考一些文章，把他們的智慧總結於此。希望對大家有所幫助。

一、多線程中創建等待窗體

 　　在winform程序開發中，計算機經常會執行一些比較耗時的任務，如大量數據的查詢操作、較為復雜的業務處理等，這些任務往往需要耗時幾秒到幾十秒鍾的時間，在這些任務執行期間winform程序窗體不再響應任何鼠標和鍵盤事件，出現假死狀態，用戶體驗很差。

　　一個比較好的解決辦法是，在這些任務執行期間在界面前端顯示一個等待窗體，告訴用戶任務正在執行中。

1.1 開發等待窗體

窗體中有一個PictureBox控件和兩個Lable控件，PictureBox控件的Image屬性為一張動態圖片。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using NavManager.Common;

namespace NavManager.Utils
{
    public partial class WaitForm : Form
    {
        public WaitForm()
        {            
            InitializeComponent();
            SetText("");
        }

        private delegate void SetTextHandler(string text);
        public void SetText(string text)
        {
            if (this.label2.InvokeRequired)
            {
                this.Invoke(new SetTextHandler(SetText), text);
            }
            else
            {
                this.label2.Text = text;
            }
        }
    }
}

 

1.2 提供訪問等待窗體的接口

編寫類WaitFormService

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;
using System.Windows.Forms;

namespace NavManager.Utils
{
    /// <summary>
    /// Using Singleton Design Pattern
    /// </summary>
    public class WaitFormService
    {
        public static void CreateWaitForm()
        {
            WaitFormService.Instance.CreateForm();
        }

        public static void CloseWaitForm()
        {
            WaitFormService.Instance.CloseForm();
        }

        public static void SetWaitFormCaption(string text)
        {
            WaitFormService.Instance.SetFormCaption(text);
        }

        private static WaitFormService _instance;
        private static readonly Object syncLock = new Object();

        public static WaitFormService Instance
        {
            get 
            {
                if (WaitFormService._instance == null)
                {
                    lock (syncLock)
                    {
                        if (WaitFormService._instance == null)
                        {
                            WaitFormService._instance = new WaitFormService();
                        }
                    }
                }
                return WaitFormService._instance;
            }
        }

        private WaitFormService()
        {
        }

        private Thread waitThread;
        private WaitForm waitForm;

        public void CreateForm()
        {
            if (waitThread != null)
            {
                try
                {
                    waitThread.Abort();
                }
                catch (Exception)
                {
                }
            }

            waitThread = new Thread(new ThreadStart(delegate()
            {
                waitForm = new WaitForm();
                Application.Run(waitForm);
            }));
            waitThread.Start();
        }

        public void CloseForm()
        {
            if (waitThread != null)
            {
                try
                {
                    waitThread.Abort();
                }
                catch (Exception)
                {
                }
            }
        }

        public void SetFormCaption(string text)
        {
            if (waitForm != null)
            {
                try
                {
                    waitForm.SetText(text);
                }
                catch (Exception)
                {
                }
            }
        }

    }
}

 

1.3 使用WaitFormService提供的接口

 try
    {
        WaitFormService.CreateWaitForm();
        Assembly asmb = Assembly.GetExecutingAssembly();
        Object obj = asmb.CreateInstance(className);
        Form frm = obj as Form;
        this.ShowMenu(frm);
        WaitFormService.CloseWaitForm();
    }
    catch (Exception ex)
    {
        WaitFormService.CloseWaitForm();
    }

 

 

 

參考文章

1. 飄落紙飛機，C# winform 多線程中創建等待窗體，2011。