I have a XML file, with a structure like
<items>
<item>
<someDetail>
A value here
</someDetail>
</item>
<item>
<someDetail>
Another value here
</someDetail>
</item>
</items>
With multiple items in it.
I want to deserialize the XML on session start ideally, to turn the XML data to objects based on a class (c# asp.net 4)
I have tried several ways with either no success, or a solution which seems clunky and inelegant.
What would people suggest?
I have tried using the xsd.exe tool, and have tried with the xml reader class, as well as usin XElement class to loop through the xml and then create new someObject(props).
These maybe the best and/or only way, but with it being so easy for database sources using the entities framework, I wondered if there was a similar way to do the same but from a xml source.
The best way to deserialize XML it to create a class that corresponds to the XML structure into which the XML data will deserialize.
The latest serialization technology uses Data Contracts and the DataContractSerializer.
You decorate the class I mentioned above with DataMember and DataItem attributes and user the serializer to deserialize.
I'd use directly the .NET XML serialization - classes declarations:
public class Item {
[XmlElement("someDetail")]
public string SomeDetail;
} // class Item
[XmlRoot("items")]
public class MyData {
[XmlElement("item")]
public List<Item> Items;
public static MyData Deserialize(Stream source)
{
XmlSerializer serializer = new XmlSerializer(typeof(MyData));
return serializer.Deserialize(source) as MyData;
} // Deserialize
} // class MyData
and then to read the XML:
using (FileStream fs = new FileStream(#"c:\temp\items.xml", FileMode.Open, FileAccess.Read)) {
MyData myData = MyData.Deserialize(fs);
}
I've concluded is there is not simple unified mechanism (probably due to the inherent complexities involved with non trivial cases - this question always crops up in the context of simple scenarios like your example xml).
Xml serialization is pretty easy to use. For your example, you would just have to create a class to contain a items and another class for the actual item. You might have to apply some attributes to get everything to work correctly, but the coding will not be much. Then it's as easy as -
var serializer = new XmlSerializer(typeof(ItemsContainer));
var items = serializer.Deserialize(...) as ItemsContainer;
Datasets are sometimes considered "yesterday tech" but I use them when they solve the problem well, and you can leverage the designer. The generated code is not pretty but the bottom line is you can persist to a database via the auto generated adapters and to XML using a method right on the data set. You can read it in this way as well.
XSD.exe isn't that bad once you get used to it. I printed the help to a text file and included it in my solutions for a while. When you use the /c option to create classes, you get clean code that can be used with the XmlSerialzier.
Visual Studio 2010 (maybe other versions too) has an XML menu which appears when you have an Xml file open and from that you can also generate an XSD from sample Xml. So in a couple of steps you could take your example xml and generate the XSD, then run it through XSD.exe and use the generated classes with a couple of lines XmlSerializer code... it feels like a lot of machinations but you get used to it.
Related
I've been scouring the web at MSDN and Google, for an answer to the following question.
How do I serialize a collection that is named as follows in c#?
<foocollection>
<fooitem1></fooitem1>
<fooitem2></fooitem2>
...
</foocollection>
I saw that you can do this in DataContract:
[CollectionDataContract(Name="foocollection", ItemName = "fooitem")]
public class FooCollection<T> : List<T> {
public FooCollection(){}
public FooCollection(T[] items){
foreach(var i in items){
Add(i);
}
}
}
The serializer is the default XML serializer from ASP.NET Web API. This code assumes that the XML posted above is coming from the client.
I have successfully serialized the above as dynamic, but dynamic isn't going to be an acceptable solution.
How would I accomplish serialization successfully using any of the below namespaces, or others, with the caveat that I can serialize to the above class? I'm willing to add extra classes as necessary to make the above work just as long as I don't have to make a class for every item in the collection.
System.ComponentModel.DataAnnotations
System.Xml.Serialization
Thank you very much in advance.
Since You didn't mention what method of xml serialization you're using, it's hard to tell, but you probably should be using DataContractSerializer in order to enable DataContract attributes. To utilize CollectionDataContractAttribute you also should have collection class that you put said attribute to, like in this example
I am looking for suggestions on how to best attack my problem.
I have a web application that will utilize a database and XML file as its data source.
Updating the DB is no issue, dealing with the XML file is.
First understand the web app is a bypass to a current(and bad performing production system). So there is no flexibility there.
So in case of the XML file the following steps will need to be performed if a user adds/update/delete a field.
Pull XML file from linux server
Parse XML file into POCOs for the UI
Recreate the XML file from the POCOs with the modifications
Push XML file to the linux server
The only good thing in my favor is that I won't have very many users using this app at a given time.
I would highly recommend looking at the DataContractSerializer for your serialization needs. Your objects would have to follow the same format as the XML, but there is no reason that you can't make those objects your model. Here is an example of marking up a POCO to serialize automatically to and from XML:
[DataContract]
public class Account
{
[DataMember, XmlAttribute]
public string Name { get; set; }
[DataMember]
public double Balance { get; set; }
}
And then you use the serialization code like this:
string serializedAccount = null;
XmlSerializer serializer = new XmlSerializer(typeof(Account));
using(StringWriter writer = new StringWriter())
{
serializer.Serialize(writer, myAccountObject);
serializedAccount = writer.ToString();
}
// serializedAccount should look something like this:
//
// <Account Name="MyName">
// <Balance>100</Balance>
// </Account>
//
// Each of the DataMember and DataContract attributes allow you to override
// names so that you can make them lower case, or provide a more meaningful
// name in your POCO.
Account deserializedAccount = null;
using(StringReader reader = new StringReader(serializedAccount))
{
deserializedAccount = serializer.DeSerialize(reader) as Account;
}
A couple things to keep in mind:
DataContract is an opt in policy. Members are ignored unless you explicitly mark them as ignored.
If you want to explicitly mark a field or property as ignored, use the [IgnoreDataMember] attribute. It can be handy even just for documentation purposes.
Nothing in the serializer prevents you from implementing INotifyPropertyChanged so all your properties can be bindable (handy for WPF)
If your XML format is not what you want to use as a model for your UI, you still may need to map properties in one object to properties in another object. This is still orders of magnitude easier than hand writing the XML reading/writing code yourself.
NOTE: if your server implements a proper SOAP web API, then WCF can take the WSDL and generate the bindings to the API and the objects that need to be serialized. There's a bit more work involved if it's a REST API, but that's also supported.
I have few XML files which I would be using in my C# code.
So far I have been using XPATH for accessing the XML node / attributes
Question is what advantage would I get if i convert the XML to Class file (XSD.EXE) and use it in terms of maintainability and code readability.
In both the cases I know if I add or remove some nodes, code needs to be changed
In my case the DLL goes into GAC.
I am just trying to get your views
Cheers,
Karthik
The beauty of converting your XML to XSD and then to a C# class is the ease in which you can grab yet another file. Your code would be something like:
XmlSerializer ser = new XmlSerializer(typeof(MyClass));
FileStream fstm = new FileStream(#"C:\mysample.xml", FileMode.Open, FileAccess.Read);
MyClass result = ser.Deserialize(fstm) as MyClass;
if(result != null)
{
// do whatever you want with your new class instance!
}
With these few lines, you now have an object that represent exactly what your XML contained, and you can access its properties as properties on the object instance - much easier than doing lots of complicated XPath queries into your XML, in my opinion.
Also, thanks to the fact you now have a XSD, you can also easily validate incoming XML files to make sure they actually do correspond to the contract defined - which causes less constant error-checking in your code (you don't have to check after each XPath to see whether there's any node(s) that actually match that expression etc.).
I've got an XSD schema which I've generated a class for using xsd.exe, and I'm trying to use XmlSerializer.Deserialize to create an instance of that class from an XML file that is supposed to conform to the XSD schema. Unfortunately the XML file has some extra elements that the schema is not expecting, which causes a System.InvalidOperationException to be thrown from Deserialize.
I've tried adding <xs:any> elements to my schema but this doesn't seem to make any difference.
My question is: is there any way to get XmlSerializer.Deserialize to ignore these extra elements?
I usually add extra properties or fields to all entity classes to pick up extra elements and attributes, looking something like the code below:
[XmlAnyAttribute]
public XmlAttribute[] AnyAttributes;
[XmlAnyElement]
public XmlElement[] AnyElements;
Depending on the complexity of your generated code, you may not find hand-inserting this code on every entity appealing. Perhaps only-slightly-less-tedious is defining these attributes in a base class and ensuring all entities inherit the base.
To give fair attribution, I was first introduced to this pattern when reading the source code for DasBlog.
I don't think there is an option to do this. You either have to fix the schema or manually modify the code generated by xsd.exe to allow the XML to be deserialized. You can also try to open the XML document + schema in Visual Studio or any other XML editor with schema support to either fix the schema or the XML document.
OK, I generated C# classes from my huge XSD file. Now I have a set of C# classes, XSD schema and actual XML data. Is there an automatic or semi-automatic way to fill these class instances with XML data that I have?
Thank you.
If you have used xsd.exe to generate the classes, then XmlSerializer should do the job...
XmlSerializer ser = new XmlSerializer(typeof(RootType));
RootType type = (RootType) ser.Deserialize(source)
You use the xml serialization/deserialization to export/import data to xml. Take a look at the XmlSerializer class. An example is on the msdn page.