Binding.Parse Event
Occurs when the value of a data-bound control changes.
[Visual Basic] Public Event Parse As ConvertEventHandler [C#] public event ConvertEventHandler Parse; [C++] public: __event ConvertEventHandler* Parse;
[JScript] In JScript, you can handle the events defined by a class, but you cannot define your own.
Event Data
The event handler receives an argument of type ConvertEventArgs containing data related to this event. The following ConvertEventArgs properties provide information specific to this event.
| Property | Description |
|---|---|
| DesiredType | Gets the data type of the desired value. |
| Value | Gets or sets the value of the ConvertEventArgs object. |
Remarks
The Format 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 object to the formatted value in the Format event. You must consequently unformat the displayed value in the Parse event.
The Parse event occurs under the following conditions:
- after the Validated event of the Control object occurs.
- when the EndCurrentEdit method of the BindingManagerBase is called.
- when the Current object of the BindingManagerBase changes (in other words, when the Position changes).
For more information about handling events, see Consuming Events.
Example
The following example creates a Binding, adds a ConvertEventHandler delegate to both the Parse and Format events, and adds the Binding to the BindingsCollection of a TextBox control through the DataBindings property. The DecimalToCurrencyString event delegate, added to the Format 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.
[Visual Basic] Private Sub DecimalToCurrencyString(sender As Object, cevent As ConvertEventArgs) ' The method converts only to string type. Test this using the DesiredType. If Not cevent.DesiredType Is 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 Not cevent.DesiredType Is GetType(Decimal) Then Exit Sub End If ' Convert the string back to decimal using the shared Parse method. cevent.Value = Decimal.Parse(cevent.Value.ToString, _ NumberStyles.Currency, nothing) End Sub Private Sub BindControl ' Create the binding first. The OrderAmount is typed as Decimal. 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 [C#] private void DecimalToCurrencyString(object sender, ConvertEventArgs cevent) { // The method converts only to string type. Test this using the DesiredType. if(cevent.DesiredType != typeof(string)) return; // Use the ToString method to format the value as currency ("c"). cevent.Value = ((decimal) cevent.Value).ToString("c"); } private void CurrencyStringToDecimal(object sender, ConvertEventArgs cevent) { // The method converts back to decimal type only. if(cevent.DesiredType != typeof(decimal)) return; // Converts the string back to decimal using the static Parse method. cevent.Value = Decimal.Parse(cevent.Value.ToString(), NumberStyles.Currency, null); } private void BindControl() { // Creates the binding first. The OrderAmount is typed as Decimal. Binding b = new Binding ("Text", ds, "customers.custToOrders.OrderAmount"); // Add the delegates to the event. b.Format += new ConvertEventHandler(DecimalToCurrencyString); b.Parse += new ConvertEventHandler(CurrencyStringToDecimal); text1.DataBindings.Add(b); } [C++] private: void DecimalToCurrencyString(Object* /*sender*/, ConvertEventArgs* cevent) { // The method converts only to string type. Test this using the DesiredType. if(cevent->DesiredType != __typeof(String)) return; // Use the ToString method to format the value as currency ("c"). cevent->Value = (*__try_cast<Decimal*>(cevent->Value)).ToString(S"c"); } void CurrencyStringToDecimal(Object* /*sender*/, ConvertEventArgs* cevent) { // The method converts back to decimal type only. if(cevent->DesiredType != __typeof(Decimal)) return; // Converts the string back to decimal using the static Parse method. cevent->Value = __box(Decimal::Parse(cevent->Value->ToString(), NumberStyles::Currency, 0)); } void BindControl() { // Creates the binding first. The OrderAmount is typed as Decimal. Binding* b = new Binding (S"Text", ds, S"customers.custToOrders.OrderAmount"); // Add the delegates to the event. b->Format += new ConvertEventHandler(this, &Form1::DecimalToCurrencyString); b->Parse += new ConvertEventHandler(this, &Form1::CurrencyStringToDecimal); text1->DataBindings->Add(b); } [JScript] private function DecimalToCurrencyString(sender, cevent : ConvertEventArgs) { // The method converts only to string type. Test this using the DesiredType. if(cevent.DesiredType != String.GetType()) return; cevent.Value = (Decimal(cevent.Value)).ToString("c"); } private function CurrencyStringToDecimal(sender, cevent : ConvertEventArgs) { // The method converts back to decimal type only. if(cevent.DesiredType != Decimal.GetType()) return; // Converts the string back to decimal using the static Parse method. cevent.Value = Decimal.Parse(cevent.Value.ToString(), NumberStyles.Currency, null); } private function BindControl() { // Creates the binding first. The OrderAmount is a Decimal type. var b : Binding = new Binding ("Text", ds, "Suppliers.CompanyName"); // Add the delegates to the event. b.add_Format(DecimalToCurrencyString); b.add_Parse(CurrencyStringToDecimal); text1.DataBindings.Add(b); }
Requirements
Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family
See Also
Binding Class | Binding Members | System.Windows.Forms Namespace | Format | OnParse | PositionChanged | CurrentChanged