Overview in Windows Forms ComboBoxAutoComplete(Classic)
The ComboBoxAutoComplete control combines a combo box control with an AutoComplete control to provide autocompletion for that instance of the combo box.
The ComboBoxAutoComplete control can be used on a form to provide autocompletion for one or several edit controls (text box and combo box). However, when the requirement is that each combo box requires data from a different datasource, it is necessary to use one AutoComplete control for each combo box. In this case, it is more efficient for the combo box control itself to include the AutoComplete control to be used for its auto completion.
The ComboBoxAutoComplete control fulfills this need. It derives from the Windows Forms combo box control and holds its own AutoComplete control that provides autocompletion for the combo box.
Choose between different combobox controls
You can refer to the different combobox controls here.