CODEWITHSUNDEEP
c#winformscombobox
mathgenius
mathgenius

Reputation: 513

Prevent ComboBox dropdown and its AutoComplete dropdown appearance conflict

I have a ComboBox whose DropDownStyle is DropDown, allowing the user to type into it and its AutoCompleteMode is Suggest. The problem is that if the ComboBox is currently open and the user starts typing into it the auxiliary drop-down list appears but clicking on an item from it actually selects the item from the ComboBox's original drop-down list residing under the mouse at the time of click.

I would prefer if while the ComboBox's drop-down list is open the user could not type into it and would like to know if there is a more elegant solution than:

  1. Setting the AutoCompleteMode to None when the ComboBox is open
  2. Possibly changing the DropDownStyle to DropDownList on the OnClick event (haven't tried, but the theory is sound)
  3. Manipulating (or restricting) the entered text while the list is open
  4. Similar

Upvotes: 5

Views: 3973

Answers (1)

Reza Aghaei
Reza Aghaei

Reputation: 125277

As an option you can handle KeyPress event of the ComboBox and close the dropdown. It keeps the autocomplete menu open, but closes dropdown:

private void comboBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    this.comboBox1.DroppedDown = false;
}

As another option, you can handle DropDown and DropDownClosed events of the ComboBox and disable autocomplete in DropDown and enable it again in DropDownClosed event:

private void comboBox1_DropDown(object sender, EventArgs e)
{
    this.comboBox1.AutoCompleteMode = AutoCompleteMode.None;
}
private void comboBox1_DropDownClosed(object sender, EventArgs e)
{
    this.comboBox1.AutoCompleteMode = AutoCompleteMode.Suggest;
}

You can create a new class deriving from ComboBox and override corresponding OnXXXX methods and put the logic there. This way you encapsulate the fix in the control class instead of handling events in your form and will have a reusable bug-free control and a more clean code.

Upvotes: 9

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