HandyControl/src/Shared/HandyControl_Shared/Controls/StepBar/StepBar.cs

using System;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Input;
using System.Windows.Media;
using HandyControl.Data;
using HandyControl.Interactivity;
using HandyControl.Tools;

namespace HandyControl.Controls
{
    [StyleTypedProperty(Property = "ItemContainerStyle", StyleTargetType = typeof(StepBarItem))]
    [DefaultEvent("StepChanged")]
    [TemplatePart(Name = ElementProgressBarBack, Type = typeof(ProgressBar))]
    public class StepBar : ItemsControl
    {
        private ProgressBar _progressBarBack;

        private int _oriStepIndex = -1;

        #region Constants

        private const string ElementProgressBarBack = "PART_ProgressBarBack";

        #endregion Constants

        public StepBar()
        {
            CommandBindings.Add(new CommandBinding(ControlCommands.Next, (s, e) => Next()));
            CommandBindings.Add(new CommandBinding(ControlCommands.Prev, (s, e) => Prev()));
            ItemContainerGenerator.StatusChanged += ItemContainerGenerator_StatusChanged;
        }

        private void ItemContainerGenerator_StatusChanged(object sender, EventArgs e)
        {
            if (ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
            {
                var count = Items.Count;
                if (count <= 0) return;

                for (var i = 0; i < count; i++)
                {
                    if (ItemContainerGenerator.ContainerFromIndex(i) is StepBarItem stepBarItem)
                    {
                        stepBarItem.Index = i + 1;
                    }
                }

                if (_oriStepIndex > 0)
                {
                    StepIndex = _oriStepIndex;
                    _oriStepIndex = -1;
                }
                else
                {
                    OnStepIndexChanged(StepIndex);
                }
            }
        }

        protected override bool IsItemItsOwnContainerOverride(object item) => item is StepBarItem;

        protected override DependencyObject GetContainerForItemOverride() => new StepBarItem();

        /// <summary>
        ///     步骤改变事件
        /// </summary>
        public static readonly RoutedEvent StepChangedEvent =
            EventManager.RegisterRoutedEvent("StepChanged", RoutingStrategy.Bubble,
                typeof(EventHandler<FunctionEventArgs<int>>), typeof(StepBar));

        /// <summary>
        ///     步骤改变事件
        /// </summary>
        [Category("Behavior")]
        public event EventHandler<FunctionEventArgs<int>> StepChanged
        {
            add => AddHandler(StepChangedEvent, value);
            remove => RemoveHandler(StepChangedEvent, value);
        }

        public static readonly DependencyProperty StepIndexProperty = DependencyProperty.Register(
            "StepIndex", typeof(int), typeof(StepBar), new FrameworkPropertyMetadata(ValueBoxes.Int0Box, 
                FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, OnStepIndexChanged, CoerceStepIndex));

        private static object CoerceStepIndex(DependencyObject d, object basevalue)
        {
            var ctl = (StepBar)d;
            var stepIndex = (int) basevalue;
            if (ctl.Items.Count == 0 && stepIndex > 0)
            {
                ctl._oriStepIndex = stepIndex;
                return ValueBoxes.Int0Box;
            }

            return stepIndex < 0
                ? ValueBoxes.Int0Box
                : stepIndex >= ctl.Items.Count
                    ? ctl.Items.Count == 0 ? 0 : ctl.Items.Count - 1
                    : basevalue;
        }

        private static void OnStepIndexChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var ctl = (StepBar) d;
            ctl.OnStepIndexChanged((int)e.NewValue);
        }

        private void OnStepIndexChanged(int stepIndex)
        {
            for (var i = 0; i < stepIndex; i++)
            {
                if (ItemContainerGenerator.ContainerFromIndex(i) is StepBarItem stepItemFinished)
                {
                    stepItemFinished.Status = StepStatus.Complete;
                }
            }

            for (var i = stepIndex + 1; i < Items.Count; i++)
            {
                if (ItemContainerGenerator.ContainerFromIndex(i) is StepBarItem stepItemFinished)
                {
                    stepItemFinished.Status = StepStatus.Waiting;
                }
            }

            if (ItemContainerGenerator.ContainerFromIndex(stepIndex) is StepBarItem stepItemSelected)
                stepItemSelected.Status = StepStatus.UnderWay;
            _progressBarBack?.BeginAnimation(RangeBase.ValueProperty, AnimationHelper.CreateAnimation(stepIndex));
            
            RaiseEvent(new FunctionEventArgs<int>(StepChangedEvent, this)
            {
                Info = stepIndex
            });
        }

        public int StepIndex
        {
            get => (int)GetValue(StepIndexProperty); 
            set => SetValue(StepIndexProperty, value);
        }

        public static readonly DependencyProperty DockProperty = DependencyProperty.Register(
            "Dock", typeof(Dock), typeof(StepBar), new PropertyMetadata(Dock.Top));

        public Dock Dock
        {
            get => (Dock)GetValue(DockProperty);
            set => SetValue(DockProperty, value);
        }

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            _progressBarBack = GetTemplateChild(ElementProgressBarBack) as ProgressBar;
        }

        protected override void OnRender(DrawingContext drawingContext)
        {
            base.OnRender(drawingContext);

            var colCount = Items.Count;
            if (_progressBarBack == null || colCount <= 0) return;
            _progressBarBack.Maximum = colCount - 1;
            _progressBarBack.Value = StepIndex;

            if (Dock == Dock.Top || Dock == Dock.Bottom)
            {
                _progressBarBack.Width = (colCount - 1) * (ActualWidth / colCount);
            }
            else
            {
                _progressBarBack.Height = (colCount - 1) * (ActualHeight / colCount);
            }
        }

        public void Next() => StepIndex++;

        public void Prev() => StepIndex--;
    }
}