Fastest way to read XML
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Hi! If I have a class with a certain number of properties, which I want to save to an XML file, where it is critical that the data can be read back into the variables as fast as possible. My idea is to create an XmlTextReader and then read the values as follows:
while (reader.Read()) { if (reader.NodeType == XmlNodeType.Element) { switch (reader.LocalName) { case "Prop1": m_Prop1 = reader.ReadString(); break; case "Prop2": m_Prop2 = reader.ReadString(); break; case "Prop3": m_Prop3 = reader.ReadString(); break; case "Prop4": m_Prop4 = reader.ReadString(); break; case "Prop5": m_Prop5 = reader.ReadString(); break; case "Prop6": m_Prop6 = reader.ReadString(); break; default: break; } } }I just want to make sure that I am in fact using the fastes possible way. So can anyone think of anything faster? Thanks already in advance! -
Hi! If I have a class with a certain number of properties, which I want to save to an XML file, where it is critical that the data can be read back into the variables as fast as possible. My idea is to create an XmlTextReader and then read the values as follows:
while (reader.Read()) { if (reader.NodeType == XmlNodeType.Element) { switch (reader.LocalName) { case "Prop1": m_Prop1 = reader.ReadString(); break; case "Prop2": m_Prop2 = reader.ReadString(); break; case "Prop3": m_Prop3 = reader.ReadString(); break; case "Prop4": m_Prop4 = reader.ReadString(); break; case "Prop5": m_Prop5 = reader.ReadString(); break; case "Prop6": m_Prop6 = reader.ReadString(); break; default: break; } } }I just want to make sure that I am in fact using the fastes possible way. So can anyone think of anything faster? Thanks already in advance!Why not just use XML serialization to write the instance to XML (assuming you're able to serialize everything you need to get using XML serialization)? Example (assuming you wanted to save the XML file to disk):
// Saves the class instance to disk. string path = @"C:\MyClassInstance.xml"; XmlSerializer serializer = new XmlSerializer(typeof(MyClass)); using(StreamWriter writer = new StreamWriter(path, false)) { serializer.Serialize(writer, myInstance); // assumes myInstance is an object of the type MyClass... writer.Close(); } // Loads the class instance XML file from disk and deserializes it MyClass instance = null; string path = @"C:\MyClassInstance.xml"; if(File.Exists(path)) { XmlSerializer serializer = new XmlSerializer(typeof(MyClass)); using(StreamReader reader = new StreamReader(path)) { info = serializer.Deserialize(reader) as MyClass; reader.Close(); } }
That should be pretty fast...The most exciting phrase to hear in science, the one that heralds the most discoveries, is not 'Eureka!' ('I found it!') but 'That's funny...’
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Why not just use XML serialization to write the instance to XML (assuming you're able to serialize everything you need to get using XML serialization)? Example (assuming you wanted to save the XML file to disk):
// Saves the class instance to disk. string path = @"C:\MyClassInstance.xml"; XmlSerializer serializer = new XmlSerializer(typeof(MyClass)); using(StreamWriter writer = new StreamWriter(path, false)) { serializer.Serialize(writer, myInstance); // assumes myInstance is an object of the type MyClass... writer.Close(); } // Loads the class instance XML file from disk and deserializes it MyClass instance = null; string path = @"C:\MyClassInstance.xml"; if(File.Exists(path)) { XmlSerializer serializer = new XmlSerializer(typeof(MyClass)); using(StreamReader reader = new StreamReader(path)) { info = serializer.Deserialize(reader) as MyClass; reader.Close(); } }
That should be pretty fast...The most exciting phrase to hear in science, the one that heralds the most discoveries, is not 'Eureka!' ('I found it!') but 'That's funny...’
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Normally that would be an idea, however I don't have to serialize all of my class' properties. Those that need not be serialized are actually created from the serialized ones. So XmlSerializer is unfortunately out of the question for me.
Why do you say that using XML serialization would be out of the question just because you have some properties you might not want to serialize? If you have properties you want to hide during serialization, then just mark them with the
XmlIgnoreAttribute. There are obvious advantages to using XML serialization besides the fact that it's probably faster than rolling your own solution. It's vastly more tolerant of changes to structure of the class being serialized, and almost impossible to accidentally create malformed XML. Here's an example - enjoy...:using System; using System.IO; using System.Xml.Serialization; namespace XmlSerializationExample { class Example { /// /// The main entry point for the application. /// [STAThread] static void Main(string[] args) { MyClass mc = new MyClass(); mc.Property1 = "a"; mc.Property2 = "b"; mc.Property3 = "c"; mc.PickANumber = 1234; mc.IgnoreThisProperty = "Blahblahblahblah."; mc.Save(@"c:\serialized_myclass.xml"); MyClass mc2 = MyClass.Load(@"c:\serialized_myclass.xml"); Console.WriteLine("Deserialized Property1: {0}", mc2.Property1); Console.WriteLine("Deserialized Property2: {0}", mc2.Property2); Console.WriteLine("Deserialized Property3: {0}", mc2.Property3); Console.WriteLine("Deserialized PickANumber: {0}", mc2.PickANumber); Console.WriteLine("Deserialized ComboProperty: {0}", mc2.ComboProperty); Console.WriteLine("Deserialized IgnoreThisProperty: {0}", mc2.IgnoreThisProperty); Console.ReadLine(); } } public class MyClass { #region Fields // These fields will not be directly serialized - they are private private string _field1; private string _field2; private string _field3; private string _ignoredField; // This field will be directly serialized, since it is public // (don't do this - bad practice) public int PickANumber; #endregion Fields #region Constructor public MyClass(){} #endregion Constructor #region Properties /// /// Property1 will be serialized because it is a public property with 'get' and 'set' accessors. /// public string Property1 { get{return _field1;} set{_field1 = value;} } /// /// Property2 will be serialized because it is a public property with 'get' and 'set' accessors. /// public string Property2 { get{return _field2;} -
Why do you say that using XML serialization would be out of the question just because you have some properties you might not want to serialize? If you have properties you want to hide during serialization, then just mark them with the
XmlIgnoreAttribute. There are obvious advantages to using XML serialization besides the fact that it's probably faster than rolling your own solution. It's vastly more tolerant of changes to structure of the class being serialized, and almost impossible to accidentally create malformed XML. Here's an example - enjoy...:using System; using System.IO; using System.Xml.Serialization; namespace XmlSerializationExample { class Example { /// /// The main entry point for the application. /// [STAThread] static void Main(string[] args) { MyClass mc = new MyClass(); mc.Property1 = "a"; mc.Property2 = "b"; mc.Property3 = "c"; mc.PickANumber = 1234; mc.IgnoreThisProperty = "Blahblahblahblah."; mc.Save(@"c:\serialized_myclass.xml"); MyClass mc2 = MyClass.Load(@"c:\serialized_myclass.xml"); Console.WriteLine("Deserialized Property1: {0}", mc2.Property1); Console.WriteLine("Deserialized Property2: {0}", mc2.Property2); Console.WriteLine("Deserialized Property3: {0}", mc2.Property3); Console.WriteLine("Deserialized PickANumber: {0}", mc2.PickANumber); Console.WriteLine("Deserialized ComboProperty: {0}", mc2.ComboProperty); Console.WriteLine("Deserialized IgnoreThisProperty: {0}", mc2.IgnoreThisProperty); Console.ReadLine(); } } public class MyClass { #region Fields // These fields will not be directly serialized - they are private private string _field1; private string _field2; private string _field3; private string _ignoredField; // This field will be directly serialized, since it is public // (don't do this - bad practice) public int PickANumber; #endregion Fields #region Constructor public MyClass(){} #endregion Constructor #region Properties /// /// Property1 will be serialized because it is a public property with 'get' and 'set' accessors. /// public string Property1 { get{return _field1;} set{_field1 = value;} } /// /// Property2 will be serialized because it is a public property with 'get' and 'set' accessors. /// public string Property2 { get{return _field2;} -
Thanks, I didn't think of the XmlIgnore attribute. Just out of interest, if I added a property, would XmlSerializer still be able to read files that did not have that property yet?
The deserialization should ignore missing property values in the XML, although you might get into some trouble if you changed the type of an existing property to something that can't be coerced from the previous type (e.g. changing a string to a decimal or something), then tried to load previously serialized versions of the type. Good luck.
The most exciting phrase to hear in science, the one that heralds the most discoveries, is not 'Eureka!' ('I found it!') but 'That's funny...’
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The deserialization should ignore missing property values in the XML, although you might get into some trouble if you changed the type of an existing property to something that can't be coerced from the previous type (e.g. changing a string to a decimal or something), then tried to load previously serialized versions of the type. Good luck.
The most exciting phrase to hear in science, the one that heralds the most discoveries, is not 'Eureka!' ('I found it!') but 'That's funny...’