C# Autocomplete, how to disable custom text?

Question

Goal:

I have a working autocomplete set for a text box. Currently, data source is SQL server.

If I type any letter within the text box, some data will suggest and append to text box.

But, how can I prevent the user to use custom text? But only use data what is suggested in the Auto Complete?

Code:

customer.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
customer.AutoCompleteSource = AutoCompleteSource.CustomSource;
customer.AutoCompleteCustomSource = autotext;

Answer 1

From the Microsoft docs: https://docs.microsoft.com/en-us/dotnet/api/system.windows.forms.textbox.autocompletemode?view=netcore-3.1

It looks like AutoCompleteMode is the ticket. If you set the mode to "Suggest" it "Displays the auxiliary drop-down list associated with the edit control. This drop-down is populated with one or more suggested completion strings."

There is even an example on the same webpage.