huadongmocaceshiyi/AlarmScrollingText.cs

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Threading;

namespace PLCDataMonitor
{
    /// <summary>
    /// 滚动报警控件（跑马灯效果）
    /// </summary>
    public class AlarmScrollingText : ContentControl
    {
        private TextBlock _textBlock;
        private Border _clipBorder;
        private Storyboard _scrollStoryboard;

        public static readonly DependencyProperty TextProperty =
            DependencyProperty.Register("Text", typeof(string), typeof(AlarmScrollingText),
                new FrameworkPropertyMetadata(string.Empty, OnTextChanged));

        public string Text
        {
            get { return (string)GetValue(TextProperty); }
            set { SetValue(TextProperty, value); }
        }

        private static void OnTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var control = d as AlarmScrollingText;
            string newText = e.NewValue as string ?? string.Empty;
            control?.OnTextChanged(newText);
        }

        public AlarmScrollingText()
        {
            DefaultStyleKey = typeof(AlarmScrollingText);

            // 添加一个简单的默认样式，以防找不到模板
            this.Loaded += OnLoaded;
        }

        private void OnLoaded(object sender, RoutedEventArgs e)
        {
            // 确保获取到模板中的元素
            ApplyTemplate();

            _textBlock = GetTemplateChild("PART_TextBlock") as TextBlock;
            _clipBorder = GetTemplateChild("PART_ClipBorder") as Border;

            if (_textBlock != null && _clipBorder != null)
            {
                _textBlock.SizeChanged += (s, args) => CheckAndStartScrolling();
                _clipBorder.SizeChanged += (s, args) => CheckAndStartScrolling();

                // 初始化滚动动画
                InitializeScrollAnimation();

                // 检查是否需要滚动
                Dispatcher.BeginInvoke(DispatcherPriority.Loaded, new Action(CheckAndStartScrolling));
            }
            else
            {
                // 如果找不到模板元素，添加一个简单的 TextBlock 作为后备
                CreateFallbackUI();
            }
        }

        private void CreateFallbackUI()
        {
            var border = new Border
            {
                Background = this.Background,
                CornerRadius = new CornerRadius(4),
                ClipToBounds = true
            };

            _textBlock = new TextBlock
            {
                Text = this.Text,
                FontSize = 14,
                FontWeight = FontWeights.Bold,
                Foreground = Brushes.Red,
                TextWrapping = TextWrapping.NoWrap,
                VerticalAlignment = VerticalAlignment.Center
            };

            border.Child = _textBlock;
            this.Content = border;
            _clipBorder = border;

            _textBlock.SizeChanged += (s, args) => CheckAndStartScrolling();
            _clipBorder.SizeChanged += (s, args) => CheckAndStartScrolling();

            InitializeScrollAnimation();
            Dispatcher.BeginInvoke(DispatcherPriority.Loaded, new Action(CheckAndStartScrolling));
        }

        private void InitializeScrollAnimation()
        {
            if (_textBlock == null) return;

            _scrollStoryboard = new Storyboard();
            var doubleAnimation = new DoubleAnimation
            {
                From = 0,
                To = -500, // 初始值，稍后在 CheckAndStartScrolling 中动态更新
                Duration = TimeSpan.FromSeconds(5),
                RepeatBehavior = RepeatBehavior.Forever
            };
            Storyboard.SetTarget(doubleAnimation, _textBlock);
            Storyboard.SetTargetProperty(doubleAnimation, new PropertyPath("(UIElement.RenderTransform).(TranslateTransform.X)"));
            _scrollStoryboard.Children.Add(doubleAnimation);
        }


        private void OnTextChanged(string newText)
        {
            if (_textBlock != null)
            {
                _textBlock.Text = newText;
                // 延迟一下，等待布局更新后再检查
                Dispatcher.BeginInvoke(DispatcherPriority.Loaded, new Action(CheckAndStartScrolling));
            }
        }

        private void CheckAndStartScrolling()
        {
            if (_textBlock == null || _clipBorder == null || _scrollStoryboard == null)
                return;

            // 停止当前动画
            _scrollStoryboard.Stop(_textBlock);
            _textBlock.RenderTransform = null;

            // 如果没有报警或报警文本为"无报警"，不启动滚动
            if (string.IsNullOrWhiteSpace(Text) || Text == "无报警")
            {
                return;
            }

            // 强制更新布局以获取准确宽度
            _textBlock.UpdateLayout();
            _clipBorder.UpdateLayout();

            double textWidth = _textBlock.ActualWidth;
            double containerWidth = _clipBorder.ActualWidth;

            // 如果文本宽度小于等于容器宽度，不需要滚动
            if (textWidth <= containerWidth)
            {
                return;
            }

            // 计算滚动目标位置
            double targetOffset = -textWidth; // 滚动到文本的左边界

            // 更新动画参数
            var animation = _scrollStoryboard.Children[0] as DoubleAnimation;
            if (animation != null)
            {
                animation.From = containerWidth; // 从容器右边开始
                animation.To = targetOffset;    // 滚动到文本的左边界
                                                // 根据文本长度计算滚动速度
                double speed = Math.Max(3, Math.Abs(textWidth + containerWidth) / 50.0);
                animation.Duration = TimeSpan.FromSeconds(speed);
            }

            // 设置初始变换
            _textBlock.RenderTransform = new TranslateTransform();

            // 开始滚动动画
            _scrollStoryboard.Begin(_textBlock, true);
        }

    }
}