Create WinForms ComboBox with non-selectable items

Question

How to create combobox control with non-selectable items? For example, such groupnames or categorynames which visually divide items in dropdownlist into some groups or categories.

Answer 1

You could derive a new ComboBox class and handle the selection yourself.

Answer 2

Instead of adding strings to your combobox you could add a special class and use selected item to determine whether the item is selected or not.

public partial class Form1 : Form
{
    private class ComboBoxItem
    {
        public int Value { get; set; }
        public string Text { get; set; }
        public bool Selectable { get; set; }
    }

    public Form1() {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e) {
        this.comboBox1.ValueMember = "Value";
        this.comboBox1.DisplayMember = "Text";
        this.comboBox1.Items.AddRange(new[] {
            new ComboBoxItem() { Selectable = false, Text="Unselectable", Value=0},
            new ComboBoxItem() { Selectable = true, Text="Selectable1", Value=1},
            new ComboBoxItem() { Selectable = true, Text="Selectable2", Value=2},
            new ComboBoxItem() { Selectable = false, Text="Unselectable", Value=3},
            new ComboBoxItem() { Selectable = true, Text="Selectable3", Value=4},
            new ComboBoxItem() { Selectable = true, Text="Selectable4", Value=5},
        });

        this.comboBox1.SelectedIndexChanged += (cbSender, cbe) => {
            var cb = cbSender as ComboBox;

            if (cb.SelectedItem != null && cb.SelectedItem is ComboBoxItem && ((ComboBoxItem) cb.SelectedItem).Selectable == false) {
                // deselect item
                cb.SelectedIndex = -1;
            }
        };
    }
}

Answer 3

Have a look here on CodeProject for a readonly Combo Box, here's another article to make the readonly combo box 'decent' looking... Here's another that shows how to override the basic standard combo box to make it readonly as Sani suggested.

Hope this helps, Best regards, Tom.

Answer 4

Hi Dear

We unable to use below coding successfully.

Errors - Selectable , Text , Value

Plz help. Eagerly awaiting a reply.

new ComboBoxItem() { Selectable = false, Text="Unselectable", Value=0},