uncheckable items in CheckedListBox?

Question

In .NET framework, is it possible to set some of the items in the CheckedListBox as "uncheckable" ? I don't want to allow user to check the same items again and add them to a another existing list.

I hope I am clear. Thanks in advance.

Answer 1

I would set those items as "Indeterminate" in code, and then overwrite the "NewValue" property from the ItemCheck event when the user attempts to check/uncheck them:

public Form1()
{
    InitializeComponent();
    checkedListBox1.Items.Add("Can't check me", CheckState.Indeterminate);
}

private void checkedListBox1_ItemCheck(object sender, ItemCheckEventArgs e)
{
    if (e.CurrentValue == CheckState.Indeterminate)
    {
        e.NewValue = CheckState.Indeterminate;
    }
}

The "Can't check me" item in the CheckedListBox can't be modified, because every time the user tries to check/uncheck it, the event handler changes it back. You don't even see the UI update accordingly.

Answer 2

Matt's code is good.

Yet, why have an item in the checkedlistbox and not let it be selected?
I mean why have that item in the list.