bbwy/BBWY.Controls/BTextBoxAnimation.cs

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

namespace BBWY.Controls
{
    [StyleTypedProperty(Property = "Style", StyleTargetType = typeof(BTextBoxAnimation))]
    public class BTextBoxAnimation : BTextBox
    {
        public static readonly DependencyProperty WaterRemarkTopStateColorProperty = DependencyProperty.Register("WaterRemarkTopStateColor", typeof(Brush), typeof(BTextBoxAnimation));
        public static readonly DependencyProperty WaterRemarkStateProperty = DependencyProperty.Register("WaterRemarkState", typeof(WaterRemarkState), typeof(BTextBoxAnimation), new PropertyMetadata(WaterRemarkState.Normal, new PropertyChangedCallback((d, e) =>
        {
            if (e.OldValue != e.NewValue)
            {
                (d as BTextBoxAnimation).PlayWaterRemarkAnimation();
            }
        })));

        private TextBlock txtRemark;
        private TimeSpan animationTimeSpan = new TimeSpan(0, 0, 0, 0, 200);
        private IEasingFunction animationEasingFunction = new PowerEase() { EasingMode = EasingMode.EaseInOut };


        public Brush WaterRemarkTopStateColor
        {
            get { return GetValue(WaterRemarkTopStateColorProperty) as Brush; }
            set { SetValue(WaterRemarkTopStateColorProperty, value); }
        }

        public WaterRemarkState WaterRemarkState
        {
            get { return (WaterRemarkState)Convert.ToInt32(GetValue(WaterRemarkStateProperty)); }
            set { SetValue(WaterRemarkStateProperty, value); }
        }


        static BTextBoxAnimation()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(BTextBoxAnimation), new FrameworkPropertyMetadata(typeof(BTextBoxAnimation)));
        }
        public BTextBoxAnimation()
        {
            this.Loaded += QLTextBoxAnimation_Loaded;
        }

        public override void OnApplyTemplate()
        {
            txtRemark = GetTemplateChild("txtRemark") as TextBlock;
            base.OnApplyTemplate();
        }

        private void QLTextBoxAnimation_Loaded(object sender, RoutedEventArgs e)
        {
            if (!string.IsNullOrEmpty(Text))
                WaterRemarkState = WaterRemarkState.Top;
        }

        protected override void OnTextChanged(TextChangedEventArgs e)
        {
            base.OnTextChanged(e);
            if (!this.IsLoaded)
                return;
            if (string.IsNullOrEmpty(Text))
                WaterRemarkState = WaterRemarkState.Normal;
            else
                WaterRemarkState = WaterRemarkState.Top;
        }

        protected override void OnGotFocus(RoutedEventArgs e)
        {
            base.OnGotFocus(e);
            WaterRemarkState = WaterRemarkState.Top;
        }

        protected override void OnLostFocus(RoutedEventArgs e)
        {
            base.OnLostFocus(e);
            if (string.IsNullOrEmpty(Text))
                WaterRemarkState = WaterRemarkState.Normal;
        }

        private void PlayWaterRemarkAnimation()
        {
            var fontsize = WaterRemarkState == WaterRemarkState.Normal ? FontSize : 10.5;
            var row = WaterRemarkState == WaterRemarkState.Normal ? 1 : 0;

            var storyboard = new Storyboard();
            var daukf_Remark_FontSize = new DoubleAnimationUsingKeyFrames();
            daukf_Remark_FontSize.KeyFrames.Add(new EasingDoubleKeyFrame(fontsize, animationTimeSpan, animationEasingFunction));
            Storyboard.SetTargetProperty(daukf_Remark_FontSize, new PropertyPath("(TextBlock.FontSize)"));
            Storyboard.SetTarget(daukf_Remark_FontSize, txtRemark);
            storyboard.Children.Add(daukf_Remark_FontSize);

            var i32aukf_Remark_Row = new Int32AnimationUsingKeyFrames();
            i32aukf_Remark_Row.KeyFrames.Add(new EasingInt32KeyFrame(row, animationTimeSpan, animationEasingFunction));
            Storyboard.SetTargetProperty(i32aukf_Remark_Row, new PropertyPath("(Grid.Row)"));
            Storyboard.SetTarget(i32aukf_Remark_Row, txtRemark);
            storyboard.Children.Add(i32aukf_Remark_Row);
            storyboard.Begin();
        }
    }

    public enum WaterRemarkState
    {
        Normal, Top
    }
}