ComboBox.AutoCompleteSource Property

Gets or sets a value specifying the source of complete strings used for automatic completion.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

[BrowsableAttribute(true)]
public AutoCompleteSource AutoCompleteSource { get; set; }

Property Value

Type: System.Windows.Forms.AutoCompleteSource
One of the values of AutoCompleteSource. The options are AllSystemSources, AllUrl, FileSystem, HistoryList, RecentlyUsedList, CustomSource, and None. The default is None.

ExceptionCondition
InvalidEnumArgumentException

The specified value is not one of the values of AutoCompleteSource.

Use the AutoCompleteCustomSource, AutoCompleteMode, and AutoCompleteSource properties to create a ComboBox that automatically completes input strings by comparing the prefix being entered to the prefixes of all strings in a maintained source. This is useful for ComboBox controls in which URLs, addresses, file names, or commands will be frequently entered.

The use of the AutoCompleteCustomSource property is optional, but you must set the AutoCompleteSource property to CustomSource in order to use AutoCompleteCustomSource.

You must use the AutoCompleteMode and AutoCompleteSource properties together.

With AutoCompleteMode set to SuggestAppend and AutoCompleteSource set to ListItems, the behavior is as follows:

  • If the list of strings is empty, pressing the BACKSPACE or DELETE key does nothing.

  • If the BACKSPACE key is pressed in less than one second, the previous item is selected, or nothing is selected if the list of string is empty.

  • If the BACKSPACE key is pressed in more than one second, the first item is selected.

  • If the DELETE key is pressed, the first item is selected.

NoteNote

The operating system might limit the number of custom strings that it can display at once. For strings that contain a forward slash (/) or backward slash (\), automatic completion appends all characters only up to and including the slash.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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