Manages all Binding objects that are bound to the same data source and data member. This class is abstract.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
The enables the synchronization of data-bound controls on a Windows Form that are bound to the same data source. (For more information about simple binding a control to a data source, see the Binding class.) For example, suppose that a form contains two TextBox controls that are bound to the same data source but to different columns. The data source might be a DataTable that contains customer names, while the columns might contain the first and last names. The two controls must be synchronized in order to display the correct first and last names together for the same customer. The CurrencyManager, which inherits from the class, accomplishes this synchronization by maintaining a pointer to the current item in the data source. The TextBox controls are bound to the current item so they display the information for the same row. When the current item changes, the CurrencyManager notifies all the bound controls so that they can refresh their data. Furthermore, you can set the Position property to specify the row in the DataTable that the controls point to. To determine how many rows exist in the data source, use the Count property.
The CurrencyManager is necessary because data sources do not necessarily maintain a current-item pointer. For instance, arrays and ArrayList objects can be data sources, but they do not have a property that returns the current item. To get the current item, use the Current property.
The PropertyManager also inherits from the , and it is used to maintain the current property of an object, rather than the property of a current object in a data source. For this reason, trying to set the Position or Count property for a PropertyManager has no effect.
Solutions programmers are encouraged to bind controls directly to a BindingSource component, which acts as both a data source and data connector to the actual target data source. BindingSource greatly simplifies both simple and complex data binding, including managing currency between the control and its target.Notes to Inheritors:
When you inherit from , you must override the following abstract members: AddNew, Count, CancelCurrentEdit, Current, EndCurrentEdit, GetItemProperties, OnCurrentChanged, Position, RemoveAt, ResumeBinding, SuspendBinding, and UpdateIsBinding.
The following code example uses the BindingContext to return a for a specific data source. (The example assumes you have declared myBindingManagerBase in the Declarations section of the module.) The example then adds event delegates to the CurrentChanged and PositionChanged events. Lastly, the example contains four methods (MoveNext, MovePrevious, MoveFirst, and MoveLast) that increment or decrement the Position property, and set the Position to the first or last row in the list. The last row in the list is determined by using the Count property.
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.