Syncfusion Winforms Multiselect Combobox

Implementing MultiSelectionComboBox

The MultiSelectionComboBox is a WinForms ComboBox control that supports multiple item selection and auto-suggestion. Selected items can be displayed as removable tag chips (VisualItem mode), comma-separated text (Delimiter mode), or single-value (Normal mode). It supports data binding via DataSource/DisplayMember/ValueMember, Office-style visual themes, grouping, and a rich event model.

When to Use This Skill

• Adding a multi-select dropdown to a Windows Forms application
• Displaying selected values as tag chips with close buttons
• Binding the combo box to a DataTable, DataView, or ArrayList
• Configuring auto-suggestion behavior (AutoSuggestMode)
• Grouping dropdown items by initial character
• Styling the drop-down list or visual item tags
• Handling selection change and visual item collection events

Documentation and Navigation Guide

Getting Started

📄 Read: references/getting-started.md

• Assembly references and NuGet package setup
• Adding the control via Designer or code-behind
• Namespace imports (C# and VB.NET)
• Basic instantiation with ButtonStyle, UseVisualStyle, and Size
• Minimal working example

Display Modes & Visual Item Input

📄 Read: references/display-modes-and-visual-items.md

• DisplayMode.VisualItem — tag chips with remove buttons
• DisplayMode.DelimiterMode — comma-separated text
• DisplayMode.NormalMode — single-value selection
• AutoSizeMode: Vertical, Horizontal, None
• VisualItemInputMode: DisplayMemberMode, ValueMemberMode, VisualItemMode
• Delimiter character customization

Data Binding

📄 Read: references/data-binding.md

• Binding to ArrayList, DataView, and DataTable
• DataSource, DisplayMember, ValueMember properties
• Complete external data source binding example
• DataSourceChanged event handling

Styling & Customization

📄 Read: references/styling-and-customization.md

• Visual styles: Default, Office2016Colorful, Office2016White, Office2016Black, Office2016DarkGray
• Drop-down styling: ShowCheckBox, group header colors, item/drop-down dimensions
• Visual item tag colors: BackColor, ForeColor, SelectionColor, BorderColor
• Grouping: ShowGroups, runtime enable/disable
• Auto-suggestion modes: Begin, Match, Disabled

Events & Advanced Features

📄 Read: references/events-and-advanced-features.md

• SelectedItemCollectionChanged — when the selected items change
• VisualItemCollectionChanged — when visual item tags are added/removed
• AutoSizeModeChanged, DataSourceChanged, DropDown events
• Detecting VisualItemCollection modifications at runtime

Quick Start

using Syncfusion.Windows.Forms.Tools;
using Syncfusion.Windows.Forms;

// Create and configure the control
var combo = new MultiSelectionComboBox();
combo.ButtonStyle = ButtonAppearance.Metro;
combo.UseVisualStyle = true;
combo.Size = new System.Drawing.Size(250, 30);
combo.DisplayMode = DisplayMode.VisualItem;

// Add items manually
combo.Items.AddRange(new object[] { "Apple", "Banana", "Cherry", "Date", "Elderberry" });

this.Controls.Add(combo);

Imports Syncfusion.Windows.Forms.Tools
Imports Syncfusion.Windows.Forms

Dim combo As New MultiSelectionComboBox()
combo.ButtonStyle = ButtonAppearance.Metro
combo.UseVisualStyle = True
combo.Size = New System.Drawing.Size(250, 30)
combo.DisplayMode = DisplayMode.VisualItem
combo.Items.AddRange(New Object() {"Apple", "Banana", "Cherry"})
Me.Controls.Add(combo)

Common Patterns

Bind to a DataTable and display as tag chips

DataTable dt = new DataTable();
dt.Columns.Add("ID");
dt.Columns.Add("Name");
dt.Rows.Add("1", "Alice");
dt.Rows.Add("2", "Bob");
dt.Rows.Add("3", "Carol");

combo.DataSource = dt;
combo.DisplayMember = "Name";
combo.ValueMember = "ID";
combo.DisplayMode = DisplayMode.VisualItem;

React to selection changes

combo.SelectedItemCollectionChanged += (sender, e) =>
{
    if (e.Action == Actions.Added)
        Console.WriteLine("Added: " + e.SelectedItems[0]);
    else
        Console.WriteLine("Removed: " + e.SelectedItems[0]);
};

Apply Office 2016 Colorful theme

combo.Style = MultiSelectionComboBoxStyle.Office2016Colorful;

Key Properties