Empty XML Docuement File error

David Smith

I get an error below when an xml file is blank or empty. What to do in this case????

Error Received: There is an error in XML Document (0,0)

XmlSerializer serializer = new XmlSerializer(typeof(Colors));
TextReader textReader = new StreamReader(colorName);
colorfile = (Colors)serializer.Deserialize(textReader); Error on this line of code, What to do for this case when the file is empty??? I want to to be able to still save data to the file.
textReader .Close();

When deserializing the object is the file is empty and I get a document error. I am assuming the because do not the xml document header attributes,

13 Replies

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Vulpes13y ago
The code I posted above is replacing the existing file with a serialized 'default' Colors object i.e. the object created by using its parameterless constructor.
David Smith13y ago
Vuples how would you replace it?
David Smith13y ago
How to replace it?
Vulpes13y ago
It's the exception which is thrown if there's any error during deserialization.

Its InnerException property gives more details.

For example, in the case of an empty document, it gives a message of:

'Root element is missing'.

You could use this to pin down the situation more tightly but the bottom line is that the file can't be deserialized as it stands and, unless there's a possibility of repairing it manually, then maybe the best strategy is to replace it anyway.
David Smith13y ago
Is that the exception for any document error
David Smith13y ago
I will try this in two or so
Vulpes13y ago
Because that's the type of exception which is actually thrown when you get an error message such as: 'There is an error in XML document (0, 0).'
David Smith13y ago
why did you use InvalidOperationException ?
Vulpes13y ago
OK, I understand what you're trying to do now.

What I'd suggest is that you catch the exception if the file is blank and then just serialize a basic object to the file so it will be a valid XML document. The code would be something like this:

XmlSerializer serializer = new XmlSerializer(typeof(Colors));
TextReader textReader = new StreamReader(colorName);

try
{
colorfile = (Colors)serializer.Deserialize(textReader);
textReader.Close();
}
catch(InvalidOperationException)
{
textReader.Close();
colorfile = new Colors(); // create a basic object
using (Stream s = File.OpenWrite(colorName))
{
serializer.Serialize(s, colorfile); // serialize it to the empty file
}
}
David Smith13y ago
Actually I did not create an empty file XML with xml serializer. I was trying to break my software as much as possible. So what I did was created a file an xml file with content.

Then I deleted all the content in the file to see what would happen and I got this error.

So I was thinking what if someone create a blank file and name the file with an .xml extension.

How to handle this situation. I was thinking the file is black we add the root elements somehow.
Vulpes13y ago
What's puzzling me is how you've been able to create an empty file using the XML serializer?

I assume you can't be creating a new file as there wouldn't then be any point in deserializing it.
David Smith13y ago
Colors is the object I am deserializing.
Sunny Sharma13y ago
Hi David, I think you missed to explain "Colors".