WinForm中的等待窗口

如果在WinForm中执行一个长时间操作时，窗体就会被锁死，直到操作完成，对于操作者的体验就是死锁状态，那在.NET（.net 5以后）中，怎么实现一个并发，等待，且同步操作信息窗口呢？

第一步：首先定义一个等待窗体，为了有明确的提示，做一个等待的gif图，同步有提示信息。.

partial class LoadingForm    {        /// <summary>        /// Required designer variable.        /// </summary>        private System.ComponentModel.IContainer components = null;
        /// <summary>        /// Clean up any resources being used.        /// </summary>        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>        protected override void Dispose(bool disposing)        {            if (disposing && (components != null))            {                components.Dispose();            }            base.Dispose(disposing);        }        #region Windows Form Designer generated code        /// <summary>        /// Required method for Designer support - do not modify        /// the contents of this method with the code editor.        /// </summary>        private void InitializeComponent()        {            System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(LoadingForm));            pictureBox1 = new PictureBox();            messageLab = new Label();            ((System.ComponentModel.ISupportInitialize)pictureBox1).BeginInit();            SuspendLayout();            //             // pictureBox1            //             pictureBox1.BackColor = Color.White;            pictureBox1.Dock = DockStyle.Top;            pictureBox1.Image = (Image)resources.GetObject("pictureBox1.Image");            pictureBox1.Location = new Point(0, 0);            pictureBox1.Name = "pictureBox1";            pictureBox1.Size = new Size(647, 141);            pictureBox1.SizeMode = PictureBoxSizeMode.Zoom;            pictureBox1.TabIndex = 0;            pictureBox1.TabStop = false;            //             // messageLab            //             messageLab.BackColor = Color.Azure;            messageLab.Dock = DockStyle.Fill;            messageLab.Font = new Font("Microsoft YaHei UI", 12F, FontStyle.Bold, GraphicsUnit.Point);            messageLab.Location = new Point(0, 141);            messageLab.Name = "messageLab";            messageLab.Padding = new Padding(30, 40, 30, 5);            messageLab.Size = new Size(647, 153);            messageLab.TabIndex = 1;            messageLab.Text = "正在加载中，请等待……";            //             // LoadingForm            //             AutoScaleDimensions = new SizeF(7F, 17F);            AutoScaleMode = AutoScaleMode.Font;            ClientSize = new Size(647, 294);            Controls.Add(messageLab);            Controls.Add(pictureBox1);            Name = "LoadingForm";            ShowIcon = false;            ShowInTaskbar = false;            StartPosition = FormStartPosition.CenterScreen;            Text = "Loading";            TopMost = true;                       ((System.ComponentModel.ISupportInitialize)pictureBox1).EndInit();            ResumeLayout(false);        }        #endregion        private PictureBox pictureBox1;        private Label messageLab;    }

为了外部的实时更新提示信息，定义一个Message属性，来更新内容的提示信息控件，这里用的是this.Invoke，因为UI线程有可能与执行线程不相同。同理，当关闭窗体时，也需要处理一下。

 public partial class LoadingForm : Form {        public LoadingForm()        {            InitializeComponent();            this.FormBorderStyle = FormBorderStyle.None;        }        public string Message        {            set            {                this.Invoke(() =>                {                    messageLab.Text = value;                });            }        }        public void CloseAll()        {            this.Invoke(() =>            {                this.Close();                this.Dispose();            });        }}

第二步：定义一个等待窗体的管理类，主要有三个成员：1、Show()，是在一个线程中；2、Message属性，是设置窗体的属性，这里需要判断窗体是否存在，不存在就等待，其实可以定义重试次数，避免错误调用顺序，设置属性也是在一个线程中执行；3、Close()也是在线程中，也需要判断窗体是否存在。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace WaitForm{    public static class LoadingManage    {        static LoadingForm _loading;        public static void Show()        {            Task.Run(() =>            {                _loading = new LoadingForm();                _loading.ShowDialog();            });        }        public static void Close()        {            Task.Run(() =>            {                while (_loading == null || _loading.IsDisposed)                {                    Thread.Sleep(10);                }                _loading.CloseAll();            });        }        public static string Message        {            set            {                while (_loading == null||_loading.IsDisposed)                {                    Thread.Sleep(10);                }                Task.Run(() =>                {                    _loading.Message = value;                });            }        }    }}

封装后，调用就简单了，如下，首先Show()，然后执行密集服务，在执行过程中，可以更新Message属性，最后执行完就可以Close()了。

LoadingManage.Show();for (var i = 0; i < 3; i++){    LoadingManage.Message = $"正在执行第{i}条数据……";    Thread.Sleep(1000);}LoadingManage.Close();

下面是准备果图：

WinForm中的等待窗口

董川民