AutoCompleteCustomSource and VSHOST crash…
When a crash occurs, check the autocompletesource to remove (or manage) all null values that may be displayed in the source…
Winforms Textbox Autocomplete in c# using Linq
xyzDataContext dc = new xyzDataContext(); AutoCompleteStringCollection namesCollection = new AutoCompleteStringCollection(); var query = from c in dc.Clients select c.Company; foreach (String comp in query) { namesCollection.Add(comp); } tBoxCompany.AutoCompleteSource = AutoCompleteSource.CustomSource; tBoxCompany.AutoCompleteMode = AutoCompleteMode.SuggestAppend; tBoxCompany.AutoCompleteCustomSource = namesCollection; Result => AutoCompleteMode accept thoose values : External link : AutoComplete TextBox In WinForms AutoComplete TextBox in C#