Binding.Parse Event
Definition
Important
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Occurs when the value of a data-bound control changes.
public:
event System::Windows::Forms::ConvertEventHandler ^ Parse;public event System.Windows.Forms.ConvertEventHandler Parse;public event System.Windows.Forms.ConvertEventHandler? Parse;member this.Parse : System.Windows.Forms.ConvertEventHandler Public Custom Event Parse As ConvertEventHandler Event Type
Examples
The following code 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.
private:
void DecimalToCurrencyString( Object^ /*sender*/, ConvertEventArgs^ cevent )
{
// The method converts only to string type. Test this using the DesiredType.
if ( cevent->DesiredType != String::typeid )
{
return;
}
// Use the ToString method to format the value as currency ("c").
cevent->Value = ( (Decimal)(cevent->Value) ).ToString( "c" );
}
void CurrencyStringToDecimal( Object^ /*sender*/, ConvertEventArgs^ cevent )
{
// The method converts back to decimal type only.
if ( cevent->DesiredType != Decimal::typeid )
{
return;
}
// Converts the string back to decimal using the static Parse method.
cevent->Value = Decimal::Parse( cevent->Value->ToString(),
NumberStyles::Currency, nullptr );
}
void BindControl()
{
// Creates the binding first. The OrderAmount is typed as Decimal.
Binding^ b = gcnew Binding(
"Text", ds, "customers.custToOrders.OrderAmount" );
// Add the delegates to the event.
b->Format += gcnew ConvertEventHandler( this, &Form1::DecimalToCurrencyString );
b->Parse += gcnew ConvertEventHandler( this, &Form1::CurrencyStringToDecimal );
text1->DataBindings->Add( b );
}
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);
}
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
' 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
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 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:
When the EndCurrentEdit method of the BindingManagerBase is called.
When the Current of the BindingManagerBase changes (in other words, when the Position changes).
For more information about handling events, see Handling and Raising Events.
