Windows forms combobox запретить ввод

I have a form in C# that uses a ComboBox.
How do I prevent a user from manually inputting text in the ComboBox in C#?

this.comboBoxType.Font = new System.Drawing.Font("Arial", 15.75F);
this.comboBoxType.FormattingEnabled = true;
this.comboBoxType.Items.AddRange(new object[] {
            "a",
            "b",
            "c"});
this.comboBoxType.Location = new System.Drawing.Point(742, 364);
this.comboBoxType.Name = "comboBoxType";
this.comboBoxType.Size = new System.Drawing.Size(89, 32);
this.comboBoxType.TabIndex = 57;   

I want A B C to be the only options.

I believe you want to set the DropDownStyle to DropDownList.

this.comboBoxType.DropDownStyle = 
    System.Windows.Forms.ComboBoxStyle.DropDownList;

Alternatively, you can do this from the WinForms designer by selecting the control, going to the Properties Window, and changing the «DropDownStyle» property to «DropDownList».

I like to keep the ability to manually insert stuff, but limit the selected items to what’s in the list.
I’d add this event to the ComboBox. As long as you get the SelectedItem and not the Text, you get the correct predefined items; a, b and c.

private void cbx_LostFocus(object sender, EventArgs e)
{
  if (!(sender is ComboBox cbx)) return;
  int i;
  cbx.SelectedIndex = (i = cbx.FindString(cbx.Text)) >= 0 ? i : 0;
}

answered Jul 17, 2018 at 12:40

Why use ComboBox then?

C# has a control called Listbox. Technically a ComboBox’s difference on a Listbox is that a ComboBox can receive input, so if it’s not the control you need then i suggest you use ListBox

Listbox Consumption guide here: C# ListBox

answered Mar 9, 2015 at 2:16

I have a form in C# that uses a ComboBox.
How do I prevent a user from manually inputting text in the ComboBox in C#?

this.comboBoxType.Font = new System.Drawing.Font("Arial", 15.75F);
this.comboBoxType.FormattingEnabled = true;
this.comboBoxType.Items.AddRange(new object[] {
            "a",
            "b",
            "c"});
this.comboBoxType.Location = new System.Drawing.Point(742, 364);
this.comboBoxType.Name = "comboBoxType";
this.comboBoxType.Size = new System.Drawing.Size(89, 32);
this.comboBoxType.TabIndex = 57;   

I want A B C to be the only options.

I believe you want to set the DropDownStyle to DropDownList.

this.comboBoxType.DropDownStyle = 
    System.Windows.Forms.ComboBoxStyle.DropDownList;

Alternatively, you can do this from the WinForms designer by selecting the control, going to the Properties Window, and changing the «DropDownStyle» property to «DropDownList».

I like to keep the ability to manually insert stuff, but limit the selected items to what’s in the list.
I’d add this event to the ComboBox. As long as you get the SelectedItem and not the Text, you get the correct predefined items; a, b and c.

private void cbx_LostFocus(object sender, EventArgs e)
{
  if (!(sender is ComboBox cbx)) return;
  int i;
  cbx.SelectedIndex = (i = cbx.FindString(cbx.Text)) >= 0 ? i : 0;
}

answered Jul 17, 2018 at 12:40

Why use ComboBox then?

C# has a control called Listbox. Technically a ComboBox’s difference on a Listbox is that a ComboBox can receive input, so if it’s not the control you need then i suggest you use ListBox

Listbox Consumption guide here: C# ListBox

answered Mar 9, 2015 at 2:16

asked Sep 17, 2008 at 17:37

To add a Visual Studio GUI reference, you can find the DropDownStyle options under the Properties of the selected ComboBox:

Which will automatically add the line mentioned in the first answer to the Form.Designer.cs InitializeComponent(), like so:

this.comboBoxBatch.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;

answered Sep 23, 2014 at 21:44

Before

Method1

Method2

cmb_type.DropDownStyle=ComboBoxStyle.DropDownList

After

answered Mar 19, 2022 at 15:32

COMBOBOXID.DropDownStyle = ComboBoxStyle.DropDownList;

answered Jan 13, 2021 at 9:11