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Throughout this chapter, we have shown little error handling for brevity. In your production applications, you might want to include error handling for a variety of situations. For example, if you're working with files, you might want to trap errors indicating the file was not found.
There might also be a case where the input document could not be parsed. Some instances might be where XML data was dynamically generated and did not generate well- formed XML data.
For example, the following XML document, badxml.xml , is not well formed because it has multiple root elements:
<?xml version="1.0" encoding="utf-8" ?> <multiple> </multiple> <multiple> </multiple>
The following code would trap the parse error after successfully loading the file:
<%@ Page language="vb" Debug="true"%> <%@ Import Namespace="System.Xml"%> <script language="vb" runat="server"> Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load Dim doc As XmlDocument = New XmlDocument() Try doc.Load(Server.MapPath("badxml.xml")) Catch parseError As System.Xml.XmlException Response.write(parseError.ToString()) End Try End Sub </script>
Remember that stream-based resources, such as XmlReader and XmlWriter , support a Close method so that you can ensure that resources are appropriately closed. Always include a test in your error handlers to ensure that you properly closed all resources.
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