在设计应用程序过程中，有时候加载对象需时较长，我们可以显示一个Loading等待页面，对用户来说就比较友好了。
这个还是涉及到多线程，下面是步骤。
一、创建好Loading窗体：
一个Panel用于显示转圈动画（仿Win10的Loading），一个Loading文本标签。动画的代码来自网络。
public partial class Fm20Loading : Form { public Fm20Loading() { InitializeComponent(); //LblMessage.Text = MultiLang.Surface(null, "OnLoading", "目标对象正在加载中, 请您稍等..."); SetStyle( ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer, true); //初始化绘图timer _tmrGraphics = new UITimer { Interval = 1 }; //Invalidate()强制重绘,绘图操作在OnPaint中实现 _tmrGraphics.Tick += (sender, e) => PnlImage.Invalidate(false); _dotSize = PnlImage.Width / 10f; //初始化"点" _dots = new LoadingDot[5]; Color = Color.CadetBlue; } /// <summary> /// 构造器 /// </summary> /// <param></param> public Fm20Loading(string message) { InitializeComponent(); //双缓冲，禁擦背景 SetStyle( ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer, true); //初始化绘图timer _tmrGraphics = new UITimer { Interval = 1 }; //Invalidate()强制重绘,绘图操作在OnPaint中实现 _tmrGraphics.Tick += (sender, e) => PnlImage.Invalidate(false); _dotSize = PnlImage.Width / 10f; //初始化"点" _dots = new LoadingDot[5]; Color = Color.CadetBlue; Message = message; } private void Fm20Loading_Load(object sender, EventArgs e) { LblMessage.ForeColor = Color; if (Owner != null) { StartPosition = FormStartPosition.Manual; Location = new Point(Owner.Left, Owner.Top); Width = Owner.Width; Height = Owner.Height; } else { var screenRect = Screen.PrimaryScreen.WorkingArea; Location = new Point((screenRect.Width - Width) / 2, (screenRect.Height - Height) / 2); } Start(); } private void Fm20Loading_Shown(object sender, EventArgs e) { if (_workAction != null) { _workThread = new Thread(ExecWorkAction) { IsBackground = true }; _workThread.Start(); } } #region 属性 [Description("消息")] public string Message { get { return LblMessage.Text; } set { LblMessage.Text = value; } } [Browsable(false), Description("圆心")] public PointF CircleCenter => new PointF(PnlImage.Width / 2f, PnlImage.Height / 2f); [Browsable(false), Description("半径")] public float CircleRadius => PnlImage.Width / 2f - _dotSize; [Browsable(true), Category("Appearance"), Description("设置\"点\"的前景色")] public Color Color { get; set; } #endregion 属性 #region 字段 [Description("工作是否完成")] public bool IsWorkCompleted; [Description("工作动作")] private ParameterizedThreadStart _workAction; [Description("工作动作参数")] private object _workActionArg; [Description("工作线程")] private Thread _workThread; [Description("工作异常")] public Exception WorkException { get; private set; } [Description("点数组")] private readonly LoadingDot[] _dots; [Description("UITimer")] private readonly UITimer _tmrGraphics; [Description("ThreadingTimer")] private ThreadingTimer _tmrAction; [Description("点大小")] private float _dotSize; [Description("是否活动")] private bool _isActived; [Description("是否绘制：用于状态重置时挂起与恢复绘图")] private bool _isDrawing = true; [Description("Timer计数：用于延迟启动每个点 ")] private int _timerCount; #endregion 字段 #region 常量 [Description("动作间隔(Timer)")] private const int ActionInterval = 30; [Description("计数基数：用于计算每个点启动延迟：index * timerCountRadix")] private const int TimerCountRadix = 45; #endregion 常量 #region 方法 /// <summary> /// 设置工作动作 /// </summary> /// <param></param> /// <param></param> public void SetWorkAction(ParameterizedThreadStart workAction, object arg) { _workAction = workAction; _workActionArg = arg; } /// <summary> /// 执行工作动作 /// </summary> private void ExecWorkAction() { try { var workTask = new Task(arg => { _workAction(arg); }, _workActionArg); workTask.Start(); Task.WaitAll(workTask); } catch (Exception exception) { WorkException = exception; } finally { IsWorkCompleted = true; } } /// <summary> /// 检查是否重置 /// </summary> /// <returns></returns> private bool CheckToReset() { return _dots.Count(d => d.Opacity > 0) == 0; } /// <summary> /// 初始化点元素 /// </summary> private void CreateLoadingDots() { for (var i = 0; i < _dots.Length; ++i) _dots[i] = new LoadingDot(CircleCenter, CircleRadius); } /// <summary> /// 开始 /// </summary> public void Start() { CreateLoadingDots(); _timerCount = 0; foreach (var dot in _dots) { dot.Reset(); } _tmrGraphics.Start(); //初始化动作timer _tmrAction = new ThreadingTimer( state => { //动画动作 for (var i = 0; i < _dots.Length; i++) { if (_timerCount++ > i * TimerCountRadix) { _dots[i].LoadingDotAction(); } } //是否重置 if (CheckToReset()) { //重置前暂停绘图 _isDrawing = false; _timerCount = 0; foreach (var dot in _dots) { dot.Reset(); } //恢复绘图 _isDrawing = true; } _tmrAction.Change(ActionInterval, Timeout.Infinite); }, null, ActionInterval, Timeout.Infinite); _isActived = true; } /// <summary> /// 停止 /// </summary> public void Stop() { _tmrGraphics.Stop(); _tmrAction.Dispose(); _isActived = false; } #endregion 方法 #region 重写 protected override void OnPaint(PaintEventArgs e) { if (IsWorkCompleted) { Stop(); Close(); } } private void PnlImage_Paint(object sender, PaintEventArgs e) { if (_isActived && _isDrawing) { //抗锯齿 e.Graphics.SmoothingMode = SmoothingMode.HighQuality; using (var bitmap = new Bitmap(200, 200)) { //缓冲绘制 using (var bufferGraphics = Graphics.FromImage(bitmap)) { //抗锯齿 bufferGraphics.SmoothingMode = SmoothingMode.HighQuality; foreach (var dot in _dots) { var rectangleF = new RectangleF( new PointF(dot.Location.X - _dotSize / 2, dot.Location.Y - _dotSize / 2), new SizeF(_dotSize, _dotSize)); bufferGraphics.FillEllipse(new SolidBrush(Color.FromArgb(dot.Opacity, Color)), rectangleF); } } //贴图 e.Graphics.DrawImage(bitmap, new PointF(0, 0)); } //bmp disposed } base.OnPaint(e); } private void PnlImage_Resize(object sender, EventArgs e) { PnlImage.Height = PnlImage.Width; _dotSize = PnlImage.Width / 12f; OnResize(e); } #endregion 重写 private void LblMessage_DoubleClick(object sender, EventArgs e) { this.Close(); } }