C# WinForms app:

I want to prevent the user from changing the checked state of a list item in a CheckedListBox. I tried this:

private void lstRights_ItemCheck(object sender, ItemCheckEventArgs e)
{
    if (lstRights.SelectedIndices.Count > 0)
    {
        lstRights.SetItemCheckState(lstRights.SelectedIndices[0], e.CurrentValue);
    }
}

But it has not effect. The item is changed anyhow.

Anyone know how to do this?