12312321

TransparentTabControl.cs

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+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Windows.Forms;
+
+namespace WindowsFormsApp
+{
+    public class TransparentTabControl : TabControl
+    {
+        private List<Panel> pages = new List<Panel>();
+
+        public void MakeTransparent()
+        {
+            if (TabCount == 0) throw new InvalidOperationException();
+            var height = GetTabRect(0).Bottom;
+            // Move controls to panels
+            for (int tab = 0; tab < TabCount; ++tab)
+            {
+                var page = new Panel
+                {
+                    Left = this.Left,
+                    Top = this.Top + height,
+                    Width = this.Width,
+                    Height = this.Height - height,
+                    BackColor = Color.Transparent,
+                    Visible = tab == this.SelectedIndex
+                };
+                for (int ix = TabPages[tab].Controls.Count - 1; ix >= 0; --ix)
+                {
+                    TabPages[tab].Controls[ix].Parent = page;
+                }
+                pages.Add(page);
+                this.Parent.Controls.Add(page);
+            }
+            this.Height = height /* + 1 */;
+        }
+
+        protected override void OnSelectedIndexChanged(EventArgs e)
+        {
+            base.OnSelectedIndexChanged(e);
+            for (int tab = 0; tab < pages.Count; ++tab)
+            {
+                pages[tab].Visible = tab == SelectedIndex;
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing) foreach (var page in pages) page.Dispose();
+            base.Dispose(disposing);
+        }
+        protected override CreateParams CreateParams
+        {
+            get
+            {
+                var parms = base.CreateParams;
+                parms.Style &= ~0x02000000;  // Turn off WS_CLIPCHILDREN
+                return parms;
+            }
+        }
+    }
+}