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How to: Write Object Data to an XML File in Visual Basic 

This example writes the object from a class to an XML file using the XmlSerializer class.


This code example defines a class named Book, creates an instance of the class, and uses XML serialization to write the instance to an XML file.

Code similar to this is available as an IntelliSense code snippet. In the code snippet picker, it is located in XML. For more information, see How to: Insert Snippets Into Your Code (Visual Basic).

Public Class Book
    Public Title As String
    Public Sub New()
    End Sub
End Class

Public Sub WriteXML()
    Dim introToVB As New Book
    introToVB.Title = "Intro to Visual Basic"
    Dim writer As New System.Xml.Serialization.XmlSerializer(GetType(Book))
    Dim file As New System.IO.StreamWriter("c:\IntroToVB.xml")
    writer.Serialize(file, introToVB)
End Sub

Compiling the Code

The class must have a public constructor without parameters.

Robust Programming

The following conditions may cause an exception:

  • The class being serialized does not have a public, parameterless constructor.

  • The file exists and is read-only (IOException).

  • The path is too long (PathTooLongException).

  • The disk is full (IOException).


This example creates a new file, if the file does not already exist. If an application needs to create a file, that application needs Create access for the folder. If the file already exists, the application needs only Write access, a lesser privilege. Where possible, it is more secure to create the file during deployment, and only grant Read access to a single file, rather than Create access for a folder.

See Also