ListViewEx.cs

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace csharp_File_Shredder
{
    // ORIGINAL CREDIT TO - I MAY HAVE MODIFIED IT ?
    /// <summary>
    /// Zusammenfassung für ListViewEx.
    /// </summary>

    public class ListViewEx : ListView
    {
        #region Interop-Defines

        [DllImport("user32.dll")]
        private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wPar, IntPtr lPar);

        // ListView messages
        private const int LVM_FIRST = 0x1000;
        private const int LVM_GETCOLUMNORDERARRAY = (LVM_FIRST + 59);

        #endregion

        private struct EmbeddedControl : IEquatable<EmbeddedControl>
        {
            public Control Control;
            public int Column;
            public int Row;
            public DockStyle Dock;
            public ListViewItem Item;

            public bool Equals(EmbeddedControl obj) => (obj is EmbeddedControl embededControl) && embededControl.Control == Control;
        }

        private ArrayList _embeddedControls = new ArrayList();

        protected int[] GetColumnOrder()
        {
            IntPtr lPar = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * Columns.Count);

            IntPtr res = SendMessage(Handle, LVM_GETCOLUMNORDERARRAY, new IntPtr(Columns.Count), lPar);
            if (res.ToInt32() == 0)	// Something went wrong
            {
                Marshal.FreeHGlobal(lPar);
                return null;
            }

            int[] order = new int[Columns.Count];
            Marshal.Copy(lPar, order, 0, Columns.Count);

            Marshal.FreeHGlobal(lPar);

            return order;
        }

        protected Rectangle GetSubItemBounds(ListViewItem Item, int SubItem)
        {
            Rectangle subItemRect = Rectangle.Empty;

            if (Item == null) {
                throw new ArgumentNullException("Item");
            }

            int[] order = GetColumnOrder();
            if (order == null) {
                return subItemRect;
            }

            if (SubItem >= order.Length) {
                throw new ArgumentOutOfRangeException("SubItem " + SubItem + " out of range");
            }

            // Retrieve the bounds of the entire ListViewItem (all subitems)
            Rectangle lviBounds = Item.GetBounds(ItemBoundsPortion.Entire);
            int subItemX = lviBounds.Left;

            // Calculate the X position of the SubItem.
            // Because the columns can be reordered we have to use Columns[order[i]] instead of Columns[i] !
            ColumnHeader col;
            int i;
            for (i = 0; i < order.Length; i++) {
                col = this.Columns[order[i]];
                if (col.Index == SubItem) {
                    break;
                }

                subItemX += col.Width;
            }

            subItemRect = new Rectangle(subItemX, lviBounds.Top, this.Columns[order[i]].Width, lviBounds.Height);

            return subItemRect;
        }

        public void AddEmbeddedControl(Control c, int col, int row)
        {
            AddEmbeddedControl(c, col, row, DockStyle.Fill);
        }

        public void AddEmbeddedControl(Control c, int col, int row, DockStyle dock)
        {
            if (c == null) {
                throw new ArgumentNullException();
            }

            if (col >= Columns.Count || row >= Items.Count) {
                throw new ArgumentOutOfRangeException();
            }

            EmbeddedControl ec;
            ec.Control = c;
            ec.Column = col;
            ec.Row = row;
            ec.Dock = dock;
            ec.Item = Items[row];

            _embeddedControls.Add(ec);

            this.Controls.Add(c);
        }

        public void RemoveFirst()
        {
            RemoveItem(0);
        }

        public void RemoveItem(int index)
        {
            EmbeddedControl ec = (EmbeddedControl)_embeddedControls[index];

            if (ec.Control == null || ec.Item == null) {
                throw new ArgumentNullException();
            }

            this.Controls.Remove(ec.Control);
            _embeddedControls.Remove((object)ec);
            ec.Item.Remove();
        }

        public void RemoveAllControls()
        {
            foreach (EmbeddedControl ec in _embeddedControls) {
                this.Controls.Remove(ec.Control);
                ec.Item.Remove();
            }
            _embeddedControls.RemoveRange(0, _embeddedControls.Count);
        }

        public Control GetEmbeddedControl(int col, int row)
        {
            foreach (EmbeddedControl ec in _embeddedControls) {
                if (ec.Row == row && ec.Column == col) {
                    return ec.Control;
                }
            }
            return null;
        }

        [DefaultValue(View.LargeIcon)]
        public new View View
        {
            get {
                return base.View;
            }
            set {
                // Embedded controls are rendered only when we're in Details mode
                foreach (EmbeddedControl ec in _embeddedControls) {
                    ec.Control.Visible = (value == View.Details);
                }

                base.View = value;
            }
        }

        protected override void WndProc(ref Message m)
        {
            const int WM_PAINT = 0x000F;
            if (m.Msg == WM_PAINT) {
                if (View != View.Details) {
                    return;
                }

                // Calculate the position of all embedded controls
                foreach (EmbeddedControl ec in _embeddedControls) {
                    Rectangle rc = this.GetSubItemBounds(ec.Item, ec.Column);

                    if ((this.HeaderStyle != ColumnHeaderStyle.None) &&
                        (rc.Top < this.Font.Height)) // Control overlaps ColumnHeader
                    {
                        ec.Control.Visible = false;
                        continue;
                    } else {
                        ec.Control.Visible = true;
                    }

                    switch (ec.Dock) {
                        case DockStyle.Top:
                        rc.Height = ec.Control.Height;
                        break;
                        case DockStyle.Left:
                        rc.Width = ec.Control.Width;
                        break;
                        case DockStyle.Bottom:
                        rc.Offset(0, rc.Height - ec.Control.Height);
                        rc.Height = ec.Control.Height;
                        break;
                        case DockStyle.Right:
                        rc.Offset(rc.Width - ec.Control.Width, 0);
                        rc.Width = ec.Control.Width;
                        break;
                        case DockStyle.None:
                        rc.Size = ec.Control.Size;
                        break;
                    }

                    // Set embedded control's bounds
                    ec.Control.Bounds = rc;
                }
            }
            base.WndProc(ref m);
        }
    }
}