Occurs when the user attempts to modify protected text in the control.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
You can create an event handler for this event in your applications to determine when the user has attempted to modify text that has been marked as protected in the control. The event handler can be used to notify the user that the text the user is attempting to modify is protected or to display a dialog box that enables the user to make appropriate changes to the text. For example, if the protected area is a date, you can display a dialog box that enables the user to choose a date which can then be applied to the text of the control.
For more information about handling events, see Consuming Events.
The following code example demonstrates the use of this member. In the example, an event handler reports on the occurrence of the event. This report helps you to learn when the event occurs and can assist you in debugging. To report on multiple events or on events that occur frequently, consider replacing MessageBox.Show with Console.WriteLine or appending the message to a multiline TextBox.
To run the example code, paste it into a project that contains an instance of type RichTextBox named RichTextBox1. Then ensure that the event handler is associated with the event.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.