docs-desktop/dotnet-desktop-guide/framework/winforms/controls/how-to-customize-item-addition-with-the-windows-forms-bindingsource.md

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title	ms.date	dev_langs	helpviewer_keywords	ms.assetid
Customize Item Addition with BindingSource component	03/30/2017	csharp vb cpp	controls [Windows Forms], creating new items BindingSource component [Windows Forms], customizing item addition with examples [Windows Forms], BindingSource component BindingSource component [Windows Forms], examples	1aae11fc-6fb2-4cb9-b3d0-e0638fe77ef0

How to: Customize Item Addition with the Windows Forms BindingSource

When you use a xref:System.Windows.Forms.BindingSource component to bind a Windows Forms control to a data source, you may find it necessary to customize the creation of new items. The xref:System.Windows.Forms.BindingSource component makes this straightforward by providing the xref:System.Windows.Forms.BindingSource.AddingNew event, which is typically raised when the bound control needs to create a new item. Your event handler can provide whatever custom behavior is required (for example, calling a method on a Web service or getting a new object from a class factory).

Note

When an item is added by handling the xref:System.Windows.Forms.BindingSource.AddingNew event, the addition cannot be canceled.

Example

The following example demonstrates how to bind a xref:System.Windows.Forms.DataGridView control to a class factory by using a xref:System.Windows.Forms.BindingSource component. When the user clicks the xref:System.Windows.Forms.DataGridView control's new row, the xref:System.Windows.Forms.BindingSource.AddingNew event is raised. The event handler creates a new DemoCustomer object, which is assigned to the xref:System.ComponentModel.AddingNewEventArgs.NewObject%2A?displayProperty=nameWithType property. This causes the new DemoCustomer object to be added to the xref:System.Windows.Forms.BindingSource component's list and to be displayed in the new row of the xref:System.Windows.Forms.DataGridView control.

[!code-cppSystem.Windows.Forms.DataConnector.AddingNew#1] [!code-csharpSystem.Windows.Forms.DataConnector.AddingNew#1] [!code-vbSystem.Windows.Forms.DataConnector.AddingNew#1]

Compiling the Code

This example requires:

• References to the System, System.Data, System.Drawing and System.Windows.Forms assemblies.

See also

• xref:System.Windows.Forms.BindingNavigator
• xref:System.Windows.Forms.DataGridView
• xref:System.Windows.Forms.BindingSource
• BindingSource Component
• How to: Bind a Windows Forms Control to a Type