WinForm实现Loading等待界面

https://blog.csdn.net/qq_36240878/article/details/84024369?spm=1001.2014.3001.5506

1、LoaderForm窗体中添加PictureBox，然后添加Loading图片

2、窗体内属性设置

StartPosition :CenterScreen在屏幕中心显示

TopMost:True置顶显示

ShowInTaskbar:False不在任务栏显示

FormBorderStyle:None不显示窗体边框和标题栏

TransparencyKey:Control颜色为Control的部分透明

BackColor:Control窗体背景颜色设为Control

3、调用：

LoadingHelper.ShowLoadingScreen();//显示
LoadingHelper.CloseForm();//关闭

4、代码部分：

LoaderForm:

using System.Drawing;
using System.Windows.Forms;

namespace LaserScanMicrometer
{
    public partial class LoadingForm : Form
    {
        public LoadingForm()
        {
            InitializeComponent();
            StartPosition   = FormStartPosition.CenterScreen;
            TopMost         = true;
            ShowInTaskbar   = false;
            FormBorderStyle = FormBorderStyle.None;
            BackColor       = Color.White;
            TransparencyKey = Color.White;
        }

        /// <summary>
        /// 关闭命令
        /// </summary>
        public void closeOrder()
        {
            if (InvokeRequired)
            {
                //这里利用委托进行窗体的操作，避免跨线程调用时抛异常，后面给出具体定义
                CONSTANTDEFINE.SetUISomeInfo UIinfo = () =>
                {
                    while (!IsHandleCreated)
                    {
                        ;
                    }

                    if (IsDisposed)
                    {
                        return;
                    }

                    if (!IsDisposed)
                    {
                        Dispose();
                    }
                };
                Invoke(UIinfo);
            }
            else
            {
                if (IsDisposed)
                {
                    return;
                }

                if (!IsDisposed)
                {
                    Dispose();
                }
            }
        }

        private void LoadingForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (!IsDisposed)
            {
                Dispose(true);
            }
        }
    }

    internal class CONSTANTDEFINE
    {
        public delegate void SetUISomeInfo();
    }
}

LoadingHelper：

using System.Threading;

namespace LaserScanMicrometer
{
    public class LoadingHelper
    {
        /// <summary>
        /// 显示loading框
        /// </summary>
        public static void ShowLoadingScreen()
        {
            // Make sure it is only launched once.
            if (loadingForm != null)
            {
                return;
            }

            var thread = new Thread(ShowForm);
            thread.IsBackground = true;
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
        }

        /// <summary>
        /// 显示窗口
        /// </summary>
        private static void ShowForm()
        {
            if (loadingForm != null)
            {
                loadingForm.closeOrder();
                loadingForm = null;
            }

            loadingForm         = new LoadingForm();
            loadingForm.TopMost = true;
            loadingForm.ShowDialog();
        }

        /// <summary>
        /// 关闭窗口
        /// </summary>
        public static void CloseForm()
        {
            Thread.Sleep(50); //可能到这里线程还未起来，所以进行延时，可以确保线程起来，彻底关闭窗口
            if (loadingForm != null)
            {
                lock (syncLock)
                {
                    Thread.Sleep(50);
                    if (loadingForm != null)
                    {
                        Thread.Sleep(50); //通过三次延时，确保可以彻底关闭窗口
                        loadingForm.Invoke(new CloseDelegate(CloseFormInternal));
                    }
                }
            }
        }

        /// <summary>
        /// 关闭窗口，委托中使用
        /// </summary>
        private static void CloseFormInternal()
        {
            loadingForm.closeOrder();
            loadingForm = null;
        }

        #region 相关变量定义

        /// <summary>
        /// 定义委托进行窗口关闭
        /// </summary>
        private delegate void CloseDelegate();

        private static          LoadingForm loadingForm;
        private static readonly object      syncLock = new object(); //加锁使用

        #endregion
    }
}