ListView の列幅を自動的に調整する Behavior

AutoAdjustColumnWidthBehavior.cs

using System;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Interactivity;

namespace BehaviorSample.Views.Behaviors
{
    /// <summary>
    /// ListViewの列幅を自動的に調整する
    /// </summary>
    public class AutoAdjustColumnWidthBehavior : Behavior<ListView>
    {
        #region DependencyProperties

        #region IsAdjustOnTargetUpdated

        /// <summary>
        /// TargetUpdated時に列幅を自動調整する。
        /// BindingでNotifyOnTargetUpdatedをtrueにする必要がある。
        /// </summary>
        public bool IsAdjustOnTargetUpdated
        {
            get { return (bool)GetValue(IsAdjustOnTargetUpdatedProperty); }
            set { SetValue(IsAdjustOnTargetUpdatedProperty, value); }
        }
        /// <summary>
        /// TargetUpdated時に列幅を自動調整する。
        /// BindingでNotifyOnTargetUpdatedをtrueにする必要がある。
        /// </summary>
        public static readonly DependencyProperty IsAdjustOnTargetUpdatedProperty =
            DependencyProperty.Register(nameof(IsAdjustOnTargetUpdated), typeof(bool), typeof(AutoAdjustColumnWidthBehavior), new PropertyMetadata(true));

        #endregion

        #region IsAdjustOnMouseLeftButtonUp

        /// <summary>
        /// MouseLeftButtonUp時に列幅を自動調整する。
        /// </summary>
        public bool IsAdjustOnMouseLeftButtonUp
        {
            get { return (bool)GetValue(IsAdjustOnMouseLeftButtonUpProperty); }
            set { SetValue(IsAdjustOnMouseLeftButtonUpProperty, value); }
        }
        /// <summary>
        /// MouseLeftButtonUp時に列幅を自動調整する。
        /// </summary>
        public static readonly DependencyProperty IsAdjustOnMouseLeftButtonUpProperty =
            DependencyProperty.Register(nameof(IsAdjustOnMouseLeftButtonUp), typeof(bool), typeof(AutoAdjustColumnWidthBehavior), new PropertyMetadata(true));

        #endregion

        #region IsAdjustOnMouseWheel

        /// <summary>
        /// MouseWheel時に列幅を自動調整する。
        /// </summary>
        public bool IsAdjustOnMouseWheel
        {
            get { return (bool)GetValue(IsAdjustOnMouseWheelProperty); }
            set { SetValue(IsAdjustOnMouseWheelProperty, value); }
        }
        /// <summary>
        /// MouseWheel時に列幅を自動調整する。
        /// </summary>
        public static readonly DependencyProperty IsAdjustOnMouseWheelProperty =
            DependencyProperty.Register(nameof(IsAdjustOnMouseWheel), typeof(bool), typeof(AutoAdjustColumnWidthBehavior), new PropertyMetadata(true));

        #endregion

        #region IsAdjustOnKeyUp

        /// <summary>
        /// KeyUp時に列幅を自動調整する。
        /// </summary>
        public bool IsAdjustOnKeyUp
        {
            get { return (bool)GetValue(IsAdjustOnKeyUpProperty); }
            set { SetValue(IsAdjustOnKeyUpProperty, value); }
        }
        /// <summary>
        /// KeyUp時に列幅を自動調整する。
        /// </summary>
        public static readonly DependencyProperty IsAdjustOnKeyUpProperty =
            DependencyProperty.Register(nameof(IsAdjustOnKeyUp), typeof(bool), typeof(AutoAdjustColumnWidthBehavior), new PropertyMetadata(true));

        #endregion

        #region IsAdjustOnTouchUp

        /// <summary>
        /// TouchUp時に列幅を自動調整する。
        /// </summary>
        public bool IsAdjustOnTouchUp
        {
            get { return (bool)GetValue(IsAdjustOnTouchUpProperty); }
            set { SetValue(IsAdjustOnTouchUpProperty, value); }
        }
        /// <summary>
        /// TouchUp時に列幅を自動調整する。
        /// </summary>
        public static readonly DependencyProperty IsAdjustOnTouchUpProperty =
            DependencyProperty.Register(nameof(IsAdjustOnTouchUp), typeof(bool), typeof(AutoAdjustColumnWidthBehavior), new PropertyMetadata(true));

        #endregion

        #endregion

        /// <summary>
        /// 列幅リサイズRoutedEventハンドラ
        /// </summary>
        private readonly RoutedEventHandler ResizeColumnsEventHandler;

        /// <summary>
        /// コンストラクタ
        /// </summary>
        public AutoAdjustColumnWidthBehavior()
        {
            this.ResizeColumnsEventHandler = new RoutedEventHandler(this.ResizeColumns_OnRoutedEvent);
        }

        protected override void OnAttached()
        {
            base.OnAttached();
            this.AssociatedObject.TargetUpdated += AddItemsSourceUpdatedHandler;
            this.AssociatedObject.TargetUpdated += ResizeColumns_OnTargetUpdated;
            this.AssociatedObject.AddHandler(UIElement.MouseLeftButtonUpEvent, ResizeColumnsEventHandler, true);
            this.AssociatedObject.AddHandler(UIElement.MouseWheelEvent, ResizeColumnsEventHandler, true);
            this.AssociatedObject.AddHandler(UIElement.KeyUpEvent, ResizeColumnsEventHandler, true);
            this.AssociatedObject.AddHandler(UIElement.TouchUpEvent, ResizeColumnsEventHandler, true);
        }
        protected override void OnDetaching()
        {
            base.OnDetaching();
            this.AssociatedObject.TargetUpdated -= AddItemsSourceUpdatedHandler;
            this.AssociatedObject.TargetUpdated -= ResizeColumns_OnTargetUpdated;
            this.AssociatedObject.RemoveHandler(UIElement.MouseLeftButtonUpEvent, ResizeColumnsEventHandler);
            this.AssociatedObject.RemoveHandler(UIElement.MouseWheelEvent, ResizeColumnsEventHandler);
            this.AssociatedObject.RemoveHandler(UIElement.KeyUpEvent, ResizeColumnsEventHandler);
            this.AssociatedObject.RemoveHandler(UIElement.TouchUpEvent, ResizeColumnsEventHandler);
        }

        #region ResizeHandlers

        /// <summary>
        /// ItemsSource更新時に各列幅をリサイズする
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void AddItemsSourceUpdatedHandler(object sender, EventArgs e)
        {
            var src = this.AssociatedObject.ItemsSource;
            if (src is INotifyPropertyChanged pSrc)
            {
                WeakEventManager<INotifyPropertyChanged, PropertyChangedEventArgs>.AddHandler(
                    pSrc,
                    "PropertyChanged",
                    ResizeColumns_OnTargetUpdated);
            }
            if (src is INotifyCollectionChanged cSrc)
            {
                WeakEventManager<INotifyCollectionChanged, NotifyCollectionChangedEventArgs>.AddHandler(
                    cSrc,
                    "CollectionChanged",
                    ResizeColumns_OnTargetUpdated);
            }
        }

        /// <summary>
        /// TargetedUpdate時に各列幅をリサイズする
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ResizeColumns_OnTargetUpdated(object sender, EventArgs e)
        {
            if (IsAdjustOnTargetUpdated)
                ResizeColumns();
        }

        /// <summary>
        /// 指定のRoutedEvent時に各列幅をリサイズする
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ResizeColumns_OnRoutedEvent(object sender, RoutedEventArgs e)
        {
            if (e.RoutedEvent == UIElement.MouseLeftButtonUpEvent && !IsAdjustOnMouseLeftButtonUp)
                return;
            if (e.RoutedEvent == UIElement.MouseWheelEvent && !IsAdjustOnMouseWheel)
                return;
            if (e.RoutedEvent == UIElement.KeyUpEvent && !IsAdjustOnKeyUp)
                return;
            if (e.RoutedEvent == UIElement.TouchUpEvent && !IsAdjustOnTouchUp)
                return;

            ResizeColumns();
        }

        /// <summary>
        /// 各列幅をリサイズする
        /// </summary>
        private void ResizeColumns()
        {
            if (!(this.AssociatedObject is ListView lv))
                return;

            if (!(lv.View is GridView gv))
                return;
            foreach (var c in gv.Columns)
            {
                c.Width = 0;    //新たにNaNが設定された場合のみ調整されるため一旦0を入れる
                c.Width = double.NaN;
            }
        }

        #endregion

    }
}