public void AddFontSizeSelector(IEnumerable <int> fontSizes) { if (fontSizes.Min() < 1 || fontSizes.Max() > 7) { throw new ArgumentException("Allowable font sizes are 1 through 7"); } var fontSizeBox = new ToolStripComboBox(); fontSizeBox.Items.AddRange(fontSizes.Select(f => f.ToString()).ToArray()); fontSizeBox.Name = "fontSizeSelector"; fontSizeBox.Size = new System.Drawing.Size(25, 25); fontSizeBox.SelectedIndexChanged += (sender, o) => { var size = ((ToolStripComboBox)sender).SelectedItem; _doc.ExecCommand("FontSize", false, size); }; fontSizeBox.DropDownStyle = ComboBoxStyle.DropDownList; this.AddToolbarItem(fontSizeBox); }