How to prevent manual input into a ComboBox in C#

Question

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.

Possible duplicate of [How to disable editing of elements in combobox for c#?](https://stackoverflow.com/questions/598447/how-to-disable-editing-of-elements-in-combobox-for-c) — sɐunıɔןɐqɐp, Oct 15 '19 at 09:57

score 173 · Accepted Answer · answered Mar 10 '12 at 17:10

173

Just set your combo as a DropDownList:

this.comboBoxType.DropDownStyle = ComboBoxStyle.DropDownList;

answered Mar 10 '12 at 17:10

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1

Doing this, does not allow me to put in default 'Select A Item' text? – Demodave Sep 13 '18 at 20:19
Just add `this.comboBoxType.SelectedIndex = 0;` to set the "default" to be the first item at the end of your code block above. – KeyszerS Sep 30 '21 at 08:22

score 21 · Answer 2 · edited Oct 16 '19 at 05:18

21

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".

edited Oct 16 '19 at 05:18

Cody Gray - on strike

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answered Mar 10 '12 at 17:09

Justin Pihony

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score 8 · Answer 3 · edited Oct 16 '19 at 05:19

8

You can suppress handling of the key press by adding e.Handled = true to the control's KeyPress event:

private void Combo1_KeyPress(object sender, KeyPressEventArgs e)
{
    e.Handled = true;
}

edited Oct 16 '19 at 05:19

Cody Gray - on strike

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answered Nov 26 '12 at 08:27

sherin_

352
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2

You can still right-click selected text in the combo box and hit Cut, voila, text disappeared – ajeh Aug 28 '17 at 15:45
1

Even you can able to delete the character. – Sushil Jadhav Jan 31 '19 at 06:29

score 2 · Answer 4 · answered Jul 17 '18 at 12:40

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;
}

score 1 · Answer 5 · answered Mar 09 '15 at 02:16

1

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 09 '15 at 02:16

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How to prevent manual input into a ComboBox in C#

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