ComboBox Control: -

When we take ListBox is TextBox controls both have their own advantages and Disadvantages

TextBox: -

Advantage: - User can enter the data at Runtime

Disadvantage: - It’s not possible to display group of items to the user

ListBox: -

Advantage: - We can display group of items to user

Disadvantage: - User can’t enter any data at runtime

ComboBox is the combination of both TextBox & ListBox controls     In ComboBox control, user can enter the data at run time and also we can display group of items to the user

Properties and Methods with ComboBox Class

SNO	Property and options	Type	Description
01	Items (Collection)	Object Collection Class	Stores all the elements in the form of collection and each element is identified using index value
02	DropDownStyle         Simple         DropDown            (Default)        DropDownList	enum	Simple: ComboBox looks like TextBox and ListBox, user can enter any data at runtime and also can select any item in the list DropDown: ComboBox appearance does not change, user can enter any data at runtime and also can select any item in the list DropDownList: ComboBox appearance does not change, user cannot enter any data at runtime but can select any item in the list
03	MaxDropDownItems	int	Used set a value that how many items should be displayed to the user in drop down list
04	Sorted         True         False(Default)	bool	True: Items are arranged in the alphabetical order False: Items are not arranged in the alphabetical order

Properties at Run Time: -

SNO	Property and options	Type	Description
01	SelectedItem	object	Sets or gets the item value selected
02	SelectedIndex	object	Sets or gets index value of the item selected