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ComboBoxProperties.AllowNull Property

Gets or sets a value that specifies whether the combo box allows null values to be entered.

Namespace: DevExpress.Web

Assembly: DevExpress.Web.v23.2.dll

NuGet Package: DevExpress.Web


public bool AllowNull { get; set; }

Property Value

Type Default Description
Boolean false

true, if null values can be entered into the editor, otherwise, false.


If the AllowNull property is set to true, end-users can enter null values into the editor by clearing its text or clicking the ‘Clear’ button. In this case, the editor’s ASPxComboBox.Value property is equal to null.


If the AllowNull property is set to false, the ‘Clear’ button isn’t displayed, and the editor doesn’t accept null values. However, if the ClearButton.DisplayMode property has Always or OnHover values, the ‘Clear’ button will be displayed and an editor’s value can be cleared.

The AllowNull property is not in effect if when the SetValue method is called.

See Also