Using TableLayout in ToolStrip in the Designer

The following sample creates an extender provider for toolstrip which adds the properties/methods that make LayoutStyle.Table designable.

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.ComponentModel;

namespace Microsoft.Samples {
[ProvideProperty("ColumnSpan", typeof(ToolStripItem))]
[ProvideProperty("RowSpan", typeof(ToolStripItem))]
[ProvideProperty("Anchor", typeof(ToolStripItem))]
[ProvideProperty("Dock", typeof(ToolStripItem))]
class TableLayoutToolStrip : ToolStrip, IExtenderProvider {
public TableLayoutToolStrip() {
this.LayoutStyle = ToolStripLayoutStyle.Table;
RowCount = 3;
ColumnCount = 3;

        }

        private TableLayoutSettings TableLayoutSettings {
get {
return LayoutSettings as TableLayoutSettings;
}
}
[DefaultValue(3)]
public int RowCount {
get {
if (TableLayoutSettings != null) {
return TableLayoutSettings.RowCount;
}
return -1;
}
set {
if (TableLayoutSettings != null) {
TableLayoutSettings.RowCount = value;
}
}
}

        [DefaultValue(3)]
public int ColumnCount {
get {
if (TableLayoutSettings != null) {
return TableLayoutSettings.ColumnCount;
}
return -1;
}
set {
if (TableLayoutSettings != null) {
TableLayoutSettings.ColumnCount = value;
}

}
}

        public override System.Drawing.Size GetPreferredSize(System.Drawing.Size proposedSize) {
// be friendly if there's no items left to
// pin the control open.

if (Items.Count == 0) {
return this.DefaultSize;
}

return base.GetPreferredSize(proposedSize);
}
[DefaultValue(1)]
[DisplayName("ColumnSpan")]
public int GetColumnSpan(object target) {
return TableLayoutSettings.GetColumnSpan(target);
}

        public void SetColumnSpan(object target, int value) {
TableLayoutSettings.SetColumnSpan(target, value);
}

        [DefaultValue(1)]
[DisplayName("RowSpan")]
public int GetRowSpan(object target) {
if (TableLayoutSettings != null) {
return TableLayoutSettings.GetRowSpan(target);
}
return 1;
}
public void SetRowSpan(object target, int value) {
if (TableLayoutSettings != null) {
TableLayoutSettings.SetRowSpan(target, value);
}
}

        [Editor(typeof(System.ComponentModel.Design.CollectionEditor), typeof(System.Drawing.Design.UITypeEditor))]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public TableLayoutColumnStyleCollection ColumnStyles {
get {
if (TableLayoutSettings != null) {
return TableLayoutSettings.ColumnStyles;
}
return null;
}
}

        [Editor(typeof(System.ComponentModel.Design.CollectionEditor), typeof(System.Drawing.Design.UITypeEditor))]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public TableLayoutRowStyleCollection RowStyles {
get {
if (TableLayoutSettings != null) {
return TableLayoutSettings.RowStyles;
}
return null;
}
}

        [DisplayName("Anchor")]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public AnchorStyles GetAnchor(object target) {
ToolStripItem tsi = target as ToolStripItem;
return (tsi != null) ? tsi.Anchor : AnchorStyles.None;

        }

        public void SetAnchor(object target, AnchorStyles value) {
ToolStripItem tsi = target as ToolStripItem;
if (tsi != null) {
tsi.Anchor = value;
}
}

        [DisplayName("Dock")]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public DockStyle GetDock(object target) {
ToolStripItem tsi = target as ToolStripItem;
return (tsi != null) ? tsi.Dock : DockStyle.None;

        }

        public void SetDock(object target, DockStyle value) {
ToolStripItem tsi = target as ToolStripItem;
if (tsi != null) {
tsi.Dock = value;
}
}
#region IExtenderProvider Members

        bool IExtenderProvider.CanExtend(object extendee) {
ToolStripItem tsi = extendee as ToolStripItem;
return tsi != null && tsi.Owner == this;
}

        #endregion
}
}