ConvertEventArgs Class
Collapse the table of content
Expand the table of content

ConvertEventArgs Class


Provides data for the Format and Parse events.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public class ConvertEventArgs : EventArgs

System_CAPS_pubmethodConvertEventArgs(Object, Type)

Initializes a new instance of the ConvertEventArgs class.


Gets the data type of the desired value.


Gets or sets the value of the ConvertEventArgs.


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)


Serves as the default hash function. (Inherited from Object.)


Gets the Type of the current instance.(Inherited from Object.)


Creates a shallow copy of the current Object.(Inherited from Object.)


Returns a string that represents the current object.(Inherited from Object.)

The ConvertEventArgs is used to format and unformat values displayed by a Windows Forms control that is bound to data through a Binding object. The Format event occurs whenever a control property is bound to a value and the Parse event occurs whenever the bound value changes.

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 specify that the data should be displayed 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.

For more information about handling events, see Handling and Raising Events.

Legacy Code Example

The following code example creates a Binding, adds a ConvertEventHandler delegate to both the Parse and Format events, and uses the DataBindings property to add the Binding to the BindingsCollection of a TextBox control. The DecimalToCurrencyString event delegate, which is added to the Format event, uses the ToString method to format the bound value (a Decimal type) as currency. The CurrencyStringToDecimal event delegate, which is 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 != 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");
   // Adds the delegates to the events.
   b.Format += new ConvertEventHandler(DecimalToCurrencyString);
   b.Parse += new ConvertEventHandler(CurrencyStringToDecimal);

.NET Framework
Available since 1.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Return to top
© 2015 Microsoft