ExceptionMessageBox.Text Property
Gets or sets the text of the top-level message to display in the exception message box
Namespace: Microsoft.SqlServer.MessageBox
Assembly: Microsoft.ExceptionMessageBox (in Microsoft.ExceptionMessageBox.dll)
The default value is an empty string.
An alternate method for setting the top-level message and other user information is to create an instance of and set the desired properties of an Exception object, including Message, and assign it to the Message property of the ExceptionMessageBox object.