Occurs when the property of a control is bound to a data value.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
The event is raised when data is pushed from the data source into the control. You can handle the event to convert unformatted data from the data source into formatted data for display. When data is pulled from the control into the data source, the Parse event is raised to unformat the displayed value, then the event occurs to reformat the data for display. This ensures that the bound control displays correctly formatted data regardless of whether the user enters formatted or unformatted data in the control.
The and Parse events allow you to create custom formats for displaying data. For example, if the data in a table is of type Decimal, you can display the data in the local currency format by setting the Value property of the ConvertEventArgs to the formatted value in the event. You must consequently unformat the displayed value in the Parse event.
The first time the property is bound.
Any time the Position changes.
Whenever the data-bound list is sorted or filtered, which is accomplished when a DataView supplies the list.
The event also occurs after the Parse event. For example, when a control loses focus, its contents are parsed. Immediately afterward, as new data is pushed into the control, the event occurs allowing the new contents to be formatted.
For more information about handling events, see Consuming Events.
The following code example creates a Binding, adds a ConvertEventHandler delegate to both the Parse and events, and adds the Binding to the BindingsCollection of a TextBox control through the DataBindings property. The DecimalToCurrencyString event delegate, added to the event, formats the bound value (a Decimal type) as currency using the ToString method. The CurrencyStringToDecimal event delegate, added to the Parse event, converts the value displayed by the control back to the Decimal type.
This example assumes the presence of a DataSet named ds.
Private Sub DecimalToCurrencyString(sender As Object, cevent As _ ConvertEventArgs) ' The method converts only to string type. Test this using the DesiredType. If cevent.DesiredType IsNot GetType(String) Then Exit Sub End If ' Use the ToString method to format the value as currency ("c"). cevent.Value = CType(cevent.Value, Decimal).ToString("c") End Sub Private Sub CurrencyStringToDecimal(sender As Object, cevent As _ ConvertEventArgs) ' The method converts back to decimal type only. If cevent.DesiredType IsNot GetType(Decimal) Then Exit Sub End If ' Converts the string back to decimal using the static ToDecimal method. cevent.Value = Decimal.Parse(cevent.Value.ToString, _ NumberStyles.Currency, nothing) End Sub Private Sub BindControl ' Creates the binding first. The OrderAmount is a Decimal type. Dim b As Binding = New Binding _ ("Text", ds, "customers.custToOrders.OrderAmount") ' Add the delegates to the event AddHandler b.Format, AddressOf DecimalToCurrencyString AddHandler b.Parse, AddressOf CurrencyStringToDecimal text1.DataBindings.Add(b) End Sub
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.