WinForm实现Loading等待界面

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，显示效果如下：

5，LoaderForm和LoadingHelper部分代码如下，ref:https://www.cnblogs.com/morewindows0/p/7107599.html

LoaderForm:

 public partial class LoaderForm : Form
    {
        public LoaderForm()
        {
            InitializeComponent();
        }
 
        /// <summary>
        /// 关闭命令
        /// </summary>
        public void closeOrder()
        {
            if (this.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 = new CONSTANTDEFINE.SetUISomeInfo(new Action(() =>
                {
                    while (!this.IsHandleCreated)
                    {
                        ;
                    }
                    if (this.IsDisposed)
                        return;
                    if (!this.IsDisposed)
                    {
                        this.Dispose();
                    }
 
                }));
                this.Invoke(UIinfo);
            }
            else
            {
                if (this.IsDisposed)
                    return;
                if (!this.IsDisposed)
                {
                    this.Dispose();
                }
            }
        }
 
        private void LoaderForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (!this.IsDisposed)
            {
                this.Dispose(true);
            }
 
        }
    }
    class CONSTANTDEFINE
    {
        public delegate void SetUISomeInfo();
    }

LoadingHelper:

  public class LoadingHelper
    {
         #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 LoaderForm loadingForm;
       private static readonly Object syncLock = new Object();  //加锁使用
 
        #endregion
 
        //private LoadingHelper()
        //{
 
        //}
 
        /// <summary>
        /// 显示loading框
        /// </summary>
        public static void ShowLoadingScreen()
        {
            // Make sure it is only launched once.
            if (loadingForm != null)
                return;
            Thread thread = new Thread(new ThreadStart(LoadingHelper.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 LoaderForm();
            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(LoadingHelper.CloseFormInternal));
                    }
                }
            }
        }
 
        /// <summary>
        /// 关闭窗口，委托中使用
        /// </summary>
        private static void CloseFormInternal()
        {
 
            loadingForm.closeOrder();
            loadingForm = null;
 
        }
 
    }

对LoaderForm窗体相关说明：

1.public delegate void SetUISomeInfo(); //定义一个委托，处理UI相关信息问题。

2.LoaderForm窗体上放置了一个label，将其AutoSize属性设置为false，并将LoaderForm的TransparencyKey属性设置为Transparent（这样设置避免在加载loading框时出现背景，loading.gif最好选择透明背景的图片）。

转： https://blog.csdn.net/qq_36240878/article/details/84024369

https://www.cnblogs.com/developer_chan/p/7107599.html