Question

is there any tool to validate configuration file?

Answer 1

Well, basically your app is the validator – if the config file is not valid, you’ll get an exception when starting up. Other than that, I’m not aware of any out-of-the-box validation support for app.config files.

In your directory C:\Program Files\Microsoft Visual Studio 9.0\Xml\Schemas, you’ll find some files called DotNetConfig.xsd / DotNetConfig20.xsd – those are Microsoft-supplied XML schema files, which you could easily use to validate any other config files you might have for validity.

The basic structure for programmatically validating your configs would be something like this:

using(StreamReader xsdReader = new StreamReader(xsdFileName))
{
    XmlSchema Schema = new XmlSchema();
    Schema = XmlSchema.Read(xsdReader, new ValidationEventHandler(XSDValidationEventHandler));

    XmlReaderSettings ReaderSettings = new XmlReaderSettings();    
    ReaderSettings.ValidationType = ValidationType.Schema;                
    ReaderSettings.Schemas.Add(Schema);   

    ReaderSettings.ValidationEventHandler += new ValidationEventHandler(XMLValidationEventHandler);

    using(XmlTextReader xmlReader = new XmlTextReader(xmlFileName))
    {
        XmlReader objXmlReader = XmlReader.Create(xmlReader, ReaderSettings);

        while (objXmlReader.Read())
        {   }
    }
}
Console.WriteLine("Successful validation completed!");

What you need to do now is supply event handlers for those event that get raised when something in the validation goes wrong – that’s about it! 🙂