• 【转】稍改进过的ListView,很好用哈


    using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Windows.Forms;
    using System.Drawing;
    using System.ComponentModel;
    using System.Collections;
    
    namespace Emao_ListView
    {
        public class MyListView : System.Windows.Forms.ListView
        {
            #region Private Members
    
            private ListViewItem m_previousItem;
            private bool m_allowReorder;
            private Color m_lineColor;
    
            #endregion
    
            #region Public Properties
    
            [Category("Behavior")]
            public bool AllowReorder
            {
                get { return m_allowReorder; }
                set { m_allowReorder = value; }
            }
    
            [Category("Appearance")]
            public Color LineColor
            {
                get { return m_lineColor; }
                set { m_lineColor = value; }
            }
    
            #endregion
    
            #region Protected and Public Methods
    
            public MyListView()
                : base()
            {
                this.FullRowSelect = true;
                this.GridLines = true;
                this.View = View.Details;
                m_allowReorder = true;
                m_lineColor = Color.Red;
                SetStyle(System.Windows.Forms.ControlStyles.DoubleBuffer |
                                  System.Windows.Forms.ControlStyles.OptimizedDoubleBuffer |
                                  System.Windows.Forms.ControlStyles.AllPaintingInWmPaint,
                                  true);
                UpdateStyles();
            }
            protected override void OnDragDrop(DragEventArgs drgevent)
            {
                if (!m_allowReorder)
                {
                    base.OnDragDrop(drgevent);
                    return;
                }
    
                // get the currently hovered row that the items will be dragged to
                Point clientPoint = base.PointToClient(new Point(drgevent.X, drgevent.Y));
                ListViewItem hoverItem = base.GetItemAt(clientPoint.X, clientPoint.Y);
    
                if (!drgevent.Data.GetDataPresent(typeof(DragItemData).ToString()) || ((DragItemData)drgevent.Data.GetData(typeof(DragItemData).ToString())).ListView == null || ((DragItemData)drgevent.Data.GetData(typeof(DragItemData).ToString())).DragItems.Count == 0)
                    return;
    
                // retrieve the drag item data
                DragItemData data = (DragItemData)drgevent.Data.GetData(typeof(DragItemData).ToString());
    
                if (hoverItem == null)
                {
                    // the user does not wish to re-order the items, just append to the end
                    for (int i = 0; i < data.DragItems.Count; i++)
                    {
                        ListViewItem newItem = (ListViewItem)data.DragItems[i];
                        base.Items.Add(newItem);
                    }
                }
                else
                {
                    // the user wishes to re-order the items
    
                    // get the index of the hover item
                    int hoverIndex = hoverItem.Index;
    
                    // determine if the items to be dropped are from
                    // this list view. If they are, perform a hack
                    // to increment the hover index so that the items
                    // get moved properly.
                    if (this == data.ListView)
                    {
                        if (hoverIndex > base.SelectedItems[0].Index)
                            hoverIndex++;
                    }
    
                    // insert the new items into the list view
                    // by inserting the items reversely from the array list
                    for (int i = data.DragItems.Count - 1; i >= 0; i--)
                    {
                        ListViewItem newItem = (ListViewItem)data.DragItems[i];
                        base.Items.Insert(hoverIndex, newItem);
                    }
                }
    
                // remove all the selected items from the previous list view
                // if the list view was found
                if (data.ListView != null)
                {
                    foreach (ListViewItem itemToRemove in data.ListView.SelectedItems)
                    {
                        data.ListView.Items.Remove(itemToRemove);
                    }
                }
    
                // set the back color of the previous item, then nullify it
                if (m_previousItem != null)
                {
                    m_previousItem = null;
                }
    
                this.Invalidate();
    
                // call the base on drag drop to raise the event
                base.OnDragDrop(drgevent);
            }
    
            protected override void OnDragOver(DragEventArgs drgevent)
            {
                if (!m_allowReorder)
                {
                    base.OnDragOver(drgevent);
                    return;
                }
    
                if (!drgevent.Data.GetDataPresent(typeof(DragItemData).ToString()))
                {
                    // the item(s) being dragged do not have any data associated
                    drgevent.Effect = DragDropEffects.None;
                    return;
                }
    
                if (base.Items.Count > 0)
                {
                    // get the currently hovered row that the items will be dragged to
                    Point clientPoint = base.PointToClient(new Point(drgevent.X, drgevent.Y));
                    ListViewItem hoverItem = base.GetItemAt(clientPoint.X, clientPoint.Y);
    
                    Graphics g = this.CreateGraphics();
    
                    if (hoverItem == null)
                    {
                        //MessageBox.Show(base.GetChildAtPoint(new Point(clientPoint.X, clientPoint.Y)).GetType().ToString());
    
                        // no item was found, so no drop should take place
                        drgevent.Effect = DragDropEffects.Move;
    
                        if (m_previousItem != null)
                        {
                            m_previousItem = null;
                            Invalidate();
                        }
    
                        hoverItem = base.Items[base.Items.Count - 1];
    
                        if (this.View == View.Details || this.View == View.List)
                        {
                            g.DrawLine(new Pen(m_lineColor, 2), new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y + hoverItem.Bounds.Height), new Point(hoverItem.Bounds.X + this.Bounds.Width, hoverItem.Bounds.Y + hoverItem.Bounds.Height));
                            g.FillPolygon(new SolidBrush(m_lineColor), new Point[] { new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y + hoverItem.Bounds.Height - 5), new Point(hoverItem.Bounds.X + 5, hoverItem.Bounds.Y + hoverItem.Bounds.Height), new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y + hoverItem.Bounds.Height + 5) });
                            g.FillPolygon(new SolidBrush(m_lineColor), new Point[] { new Point(this.Bounds.Width - 4, hoverItem.Bounds.Y + hoverItem.Bounds.Height - 5), new Point(this.Bounds.Width - 9, hoverItem.Bounds.Y + hoverItem.Bounds.Height), new Point(this.Bounds.Width - 4, hoverItem.Bounds.Y + hoverItem.Bounds.Height + 5) });
                        }
                        else
                        {
                            g.DrawLine(new Pen(m_lineColor, 2), new Point(hoverItem.Bounds.X + hoverItem.Bounds.Width, hoverItem.Bounds.Y), new Point(hoverItem.Bounds.X + hoverItem.Bounds.Width, hoverItem.Bounds.Y + hoverItem.Bounds.Height));
                            g.FillPolygon(new SolidBrush(m_lineColor), new Point[] { new Point(hoverItem.Bounds.X + hoverItem.Bounds.Width - 5, hoverItem.Bounds.Y), new Point(hoverItem.Bounds.X + hoverItem.Bounds.Width + 5, hoverItem.Bounds.Y), new Point(hoverItem.Bounds.X + hoverItem.Bounds.Width, hoverItem.Bounds.Y + 5) });
                            g.FillPolygon(new SolidBrush(m_lineColor), new Point[] { new Point(hoverItem.Bounds.X + hoverItem.Bounds.Width - 5, hoverItem.Bounds.Y + hoverItem.Bounds.Height), new Point(hoverItem.Bounds.X + hoverItem.Bounds.Width + 5, hoverItem.Bounds.Y + hoverItem.Bounds.Height), new Point(hoverItem.Bounds.X + hoverItem.Bounds.Width, hoverItem.Bounds.Y + hoverItem.Bounds.Height - 5) });
                        }
    
                        // call the base OnDragOver event
                        base.OnDragOver(drgevent);
    
                        return;
                    }
    
                    // determine if the user is currently hovering over a new
                    // item. If so, set the previous item's back color back
                    // to the default color.
                    if ((m_previousItem != null && m_previousItem != hoverItem) || m_previousItem == null)
                    {
                        this.Invalidate();
                    }
    
                    // set the background color of the item being hovered
                    // and assign the previous item to the item being hovered
                    //hoverItem.BackColor = Color.Beige;
                    m_previousItem = hoverItem;
    
                    if (this.View == View.Details || this.View == View.List)
                    {
                        g.DrawLine(new Pen(m_lineColor, 2), new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y), new Point(hoverItem.Bounds.X + this.Bounds.Width, hoverItem.Bounds.Y));
                        g.FillPolygon(new SolidBrush(m_lineColor), new Point[] { new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y - 5), new Point(hoverItem.Bounds.X + 5, hoverItem.Bounds.Y), new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y + 5) });
                        g.FillPolygon(new SolidBrush(m_lineColor), new Point[] { new Point(this.Bounds.Width - 4, hoverItem.Bounds.Y - 5), new Point(this.Bounds.Width - 9, hoverItem.Bounds.Y), new Point(this.Bounds.Width - 4, hoverItem.Bounds.Y + 5) });
                    }
                    else
                    {
                        g.DrawLine(new Pen(m_lineColor, 2), new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y), new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y + hoverItem.Bounds.Height));
                        g.FillPolygon(new SolidBrush(m_lineColor), new Point[] { new Point(hoverItem.Bounds.X - 5, hoverItem.Bounds.Y), new Point(hoverItem.Bounds.X + 5, hoverItem.Bounds.Y), new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y + 5) });
                        g.FillPolygon(new SolidBrush(m_lineColor), new Point[] { new Point(hoverItem.Bounds.X - 5, hoverItem.Bounds.Y + hoverItem.Bounds.Height), new Point(hoverItem.Bounds.X + 5, hoverItem.Bounds.Y + hoverItem.Bounds.Height), new Point(hoverItem.Bounds.X, hoverItem.Bounds.Y + hoverItem.Bounds.Height - 5) });
                    }
    
                    // go through each of the selected items, and if any of the
                    // selected items have the same index as the item being
                    // hovered, disable dropping.
                    foreach (ListViewItem itemToMove in base.SelectedItems)
                    {
                        if (itemToMove.Index == hoverItem.Index)
                        {
                            drgevent.Effect = DragDropEffects.None;
                            hoverItem.EnsureVisible();
                            return;
                        }
                    }
    
                    // ensure that the hover item is visible
                    hoverItem.EnsureVisible();
                }
    
                // everything is fine, allow the user to move the items
                drgevent.Effect = DragDropEffects.Move;
    
                // call the base OnDragOver event
                base.OnDragOver(drgevent);
            }
    
            protected override void OnDragEnter(DragEventArgs drgevent)
            {
                if (!m_allowReorder)
                {
                    base.OnDragEnter(drgevent);
                    return;
                }
    
                if (!drgevent.Data.GetDataPresent(typeof(DragItemData).ToString()))
                {
                    // the item(s) being dragged do not have any data associated
                    drgevent.Effect = DragDropEffects.None;
                    return;
                }
    
                // everything is fine, allow the user to move the items
                drgevent.Effect = DragDropEffects.Move;
    
                // call the base OnDragEnter event
                base.OnDragEnter(drgevent);
            }
    
            protected override void OnItemDrag(ItemDragEventArgs e)
            {
                if (!m_allowReorder)
                {
                    base.OnItemDrag(e);
                    return;
                }
    
                // call the DoDragDrop method
                base.DoDragDrop(GetDataForDragDrop(), DragDropEffects.Move);
    
                // call the base OnItemDrag event
                base.OnItemDrag(e);
            }
    
            protected override void OnLostFocus(EventArgs e)
            {
                // reset the selected items background and remove the previous item
                ResetOutOfRange();
    
                Invalidate();
    
                // call the OnLostFocus event
                base.OnLostFocus(e);
            }
    
            protected override void OnDragLeave(EventArgs e)
            {
                // reset the selected items background and remove the previous item
                ResetOutOfRange();
    
                Invalidate();
    
                // call the base OnDragLeave event
                base.OnDragLeave(e);
            }
    
            #endregion
            #region Private Methods
    
            private DragItemData GetDataForDragDrop()
            {
                // create a drag item data object that will be used to pass along with the drag and drop
                DragItemData data = new DragItemData(this);
    
                // go through each of the selected items and 
                // add them to the drag items collection
                // by creating a clone of the list item
                foreach (ListViewItem item in this.SelectedItems)
                {
                    data.DragItems.Add(item.Clone());
                }
    
                return data;
            }
    
            private void ResetOutOfRange()
            {
                // determine if the previous item exists,
                // if it does, reset the background and release 
                // the previous item
                if (m_previousItem != null)
                {
                    m_previousItem = null;
                }
    
            }
    
            #endregion
    
            #region DragItemData Class
    
            private class DragItemData
            {
                #region Private Members
    
                private MyListView m_listView;
                private ArrayList m_dragItems;
    
                #endregion
    
                #region Public Properties
    
                public MyListView ListView
                {
                    get { return m_listView; }
                }
    
                public ArrayList DragItems
                {
                    get { return m_dragItems; }
                }
    
                #endregion
    
                #region Public Methods and Implementation
    
                public DragItemData(MyListView listView)
                {
                    m_listView = listView;
                    m_dragItems = new ArrayList();
                }
    
                #endregion
            }
    
            #endregion
        }
    }


     改进了一点点的ListView,数据多不会闪。可以拖动行来进行排序了。 
    以前主要是自己用。就这样了 
    要启用拖放行,设置一下  AllowRecoder为true即可。另外多行选择=false

    原文:http://www.oschina.net/code/snippet_191468_13278

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  • 原文地址:https://www.cnblogs.com/anduinlothar/p/3523401.html
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