Question

I have a ComboBox with the following code:

private void comboBox1_TextChanged(object sender, EventArgs e)
{
    using (var service = WebServiceHelper.GetCoreService())
    {
        string physicianXml = service.SearchPhysicians(SessionInfo.Current.ClientCode, SessionInfo.Current.MachineName,
                                    SessionInfo.Current.Username, comboBox1.Text);

        var physicians = PhysicianItemList.FromXml(physicianXml);

        AutoCompleteStringCollection autoCompleteStringCollection = new AutoCompleteStringCollection();
        foreach (var physician in physicians.Items)
        {
            autoCompleteStringCollection.Add(physician.LastName + ", " + physician.FirstName);
        }

        comboBox1.AutoCompleteCustomSource = autoCompleteStringCollection;
        comboBox1.Select(comboBox1.Text.Length, 0);
    }
}

Basically, a user types the first few characters of a physician’s name and it should populate the auto-complete list with the top 100 matching records. It works great, but I need to associate it back to a key (either the PK from the table, or the Physician’s NPI number). It seems the AutoCompleteStringCollection doesn’t support keys. Can anyone suggest a way of doing this? There are approximately 7 million records in the table, so I don’t want to prepopulate the ComboBox.

Thanks

Answer 1

When you build your AutoCompleteStringCollection, build a Dictionary<String, int> for the name, id pairs as well. Then use some event (textbox validation or user submit/save click) to lookup and set the id. You could store the dictionary on the textbox Tag.

Edit

For some reason I thought you were working with a textbox control. Forget about the AutoCompleteStringCollection and just build a Dictionary<String, int>. For the combobox set your autocompletesource to ListItems, set the combobox display name and value and set the datasource to the dictionary.

combobox.DisplayMember = "key";
combobox.ValueMember = "value";
combobox.AutocompleteSource = AutocompleteSource.ListItems;
combobox.DataSource = myDictionary;

However you should only populate the datasource and autocomplete once when the user enters n characters in the combobox, otherwise it gets buggy. I tried to use this for a dynamic autocomplete once (eg the list clears if the user clear the text and retypes), but I had to forget about the combobox and use a hybrid textbox listbox approach much like this user