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>
        /// 堆代码 duidaima.com
        /// 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：