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 name="message"></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 name="workAction"></param>
/// <param name="arg"></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();
}
}
Loading窗体代码
internal sealed class LoadingDot
{
#region 字段/属性
[Description("圆心")] private readonly PointF _circleCenter;
[Description("半径")] private readonly float _circleRadius;
/// <summary>
/// 当前帧绘图坐标，在每次DoAction()时重新计算
/// </summary>
public PointF Location;
[Description("点相对于圆心的角度，用于计算点的绘图坐标")] private int _angle;
[Description("透明度")] private int _opacity;
[Description("动画进度")] private int _progress;
[Description("速度")] private int _speed;
[Description("透明度")]
public int Opacity => _opacity < MinOpacity ? MinOpacity : (_opacity > MaxOpacity ? MaxOpacity : _opacity);
#endregion
#region 常量
[Description("最小速度")] private const int MinSpeed = 2;
[Description("最大速度")] private const int MaxSpeed = 11;
[Description("出现区的相对角度")] private const int AppearAngle = 90;
[Description("减速区的相对角度")] private const int SlowAngle = 225;
[Description("加速区的相对角度")] private const int QuickAngle = 315;
[Description("最小角度")] private const int MinAngle = 0;
[Description("最大角度")] private const int MaxAngle = 360;
[Description("淡出速度")] private const int AlphaSub = 25;
[Description("最小透明度")] private const int MinOpacity = 0;
[Description("最大透明度")] private const int MaxOpacity = 255;
#endregion 常量
#region 构造器
public LoadingDot(PointF circleCenter, float circleRadius)
{
Reset();
_circleCenter = circleCenter;
_circleRadius = circleRadius;
}
#endregion 构造器
#region 方法
/// <summary>
/// 重新计算当前帧绘图坐标
/// </summary>
private void ReCalcLocation()
{
Location = GetDotLocationByAngle(_circleCenter, _circleRadius, _angle);
}
/// <summary>
/// 点动作
/// </summary>
public void LoadingDotAction()
{
switch (_progress)
{
case 0:
{
_opacity = MaxOpacity;
AddSpeed();
if (_angle + _speed >= SlowAngle && _angle + _speed < QuickAngle)
{
_progress = 1;
_angle = SlowAngle - _speed;
}
}
break;
case 1:
{
SubSpeed();
if (_angle + _speed >= QuickAngle || _angle + _speed < SlowAngle)
{
_progress = 2;
_angle = QuickAngle - _speed;
}
}
break;
case 2:
{
AddSpeed();
if (_angle + _speed >= SlowAngle && _angle + _speed < QuickAngle)
{
_progress = 3;
_angle = SlowAngle - _speed;
}
}
break;
case 3:
{
SubSpeed();
if (_angle + _speed >= QuickAngle && _angle + _speed < MaxAngle)
{
_progress = 4;
_angle = QuickAngle - _speed;
}
}
break;
case 4:
{
SubSpeed();
if (_angle + _speed >= MinAngle && _angle + _speed < AppearAngle)
{
_progress = 5;
_angle = MinAngle;
}
}
break;
case 5:
{
AddSpeed();
FadeOut();
}
break;
}
//移动
_angle = _angle >= (MaxAngle - _speed) ? MinAngle : _angle + _speed;
//重新计算坐标
ReCalcLocation();
}
/// <summary>
/// 淡出
/// </summary>
private void FadeOut()
{
if ((_opacity -= AlphaSub) <= 0)
_angle = AppearAngle;
}
/// <summary>
/// 重置状态
/// </summary>
public void Reset()
{
_angle = AppearAngle;
_speed = MinSpeed;
_progress = 0;
_opacity = 1;
}
/// <summary>
/// 加速
/// </summary>
private void AddSpeed()
{
if (++_speed >= MaxSpeed) _speed = MaxSpeed;
}
/// <summary>
/// 减速
/// </summary>
private void SubSpeed()
{
if (--_speed <= MinSpeed) _speed = MinSpeed;
}
#endregion 方法
/// <summary>
/// 根据半径、角度求圆上坐标
/// </summary>
/// <param name="center">圆心</param>
/// <param name="radius">半径</param>
/// <param name="angle">角度</param>
/// <returns>坐标</returns>
public static PointF GetDotLocationByAngle(PointF center, float radius, int angle)
{
var x = (float)(center.X + radius * Math.Cos(angle * Math.PI / 180));
var y = (float)(center.Y + radius * Math.Sin(angle * Math.PI / 180));
return new PointF(x, y);
}
}
绘制圆点动画的LoadingDot代码
二、窗体和动画有了，怎么使用呢？
private void ShowLoadingForm()
{
if (Debugger.IsAttached)
{
return;
}
Fm20Loading fm20Loading = new Fm20Loading
{
Name = "Fm20Loading" + DateTime.Now.Ticks
};
Thread.Sleep(100);
fm20Loading.ShowDialog();
return ;
}
private void CloseLoadingForm()
{
if (Debugger.IsAttached) return;
for (int i = (Application.OpenForms.Count-1); i >=0; i--)
{
Form tForm = Application.OpenForms[i];
string fmName = tForm.GetType().Name;
if (OString.Left(fmName,11) == "Fm20Loading")
{
tForm.Close();
}
}
}
创建和关闭页面代码
三、调用创建和关闭代码的代码（有点绕了）
try
{
Form child = ActiveChildForm(dllFormNameWithNameSpace);
if (child != null) return child;
Action handler = new Action(ShowLoadingForm);
handler.BeginInvoke(null, null); //在另外一个线程打开，否则会阻塞
Form form = OpenPluginFormInMainDomain(dllFileSimpleName, dllFormNameWithNameSpace, initParam);
if (form != null && form is Form)
{
child = form as Form;
((Fm11Base)child).RightsList = rightsList.ToLower();
((Fm11Base)child).OnLoadParams = onLoadParams;
child.Text = tagTitle;
child.MdiParent = (Form)this;
child.FormClosed += Child_FormClosed;
child.Show();
child.WindowState = FormWindowState.Maximized;
this.ActivateMdiChild(child);
if (child.HasChildren)
{
child.Controls[0].Focus();
}
CloseLoadingForm();
return child;
}
else
{
CloseLoadingForm();
return null;
throw new Exception("未找到窗体文件或加载了未知的窗体类型!");
}
}
catch (Exception ex)
{
CloseLoadingForm();
MyMsg.Information("窗体实例化出错,请重试.", ex.Message);
return null;
}
这部分可以改成你喜欢的使用环境。
如此，一个友好的加载等待页面就完成了。它和耗时后台任务提示窗口两种界面结合，可以解决大部分的友好提示界面需求。
原文地址：https://www.cnblogs.com/imes/p/9779331.html
时间： 2024-08-11 02:52:52