I have a class and I need to iterate tru each property reading the attribute name to map to my data Source the value, in the cases where I have a ICollection that property will have multiple attributes to map the correct value.
I'm using Expression trees to set the values efficiently to each property but I'm having issues to set the values to the Collection.
I think this is because I need to create an instance of that Collection but I don't know. I'm a bit lost on that one here's what I got:
[AttributeUsage(AttributeTargets.Property, AllowMultiple = true)]
public class MapToAttribute : Attribute
{
public MapToAttribute(string field)
{
Field = field;
}
public string Field { get; private set; }
}
public class MyDataClass
{
[MapTo("one")]
public int propOne { get; set; }
[MapTo("two")]
public string propTwo { get; set; }
[MapTo("item1")]
[MapTo("item2")]
[MapTo("item3")]
public ICollection<int> collection { get; set; }
}
class Program
{
static void Main(string[] args)
{
var setter = SetValues<MyDataClass>();
}
private static IEnumerable<T> SetValues<T>()
where T : new()
{
var properties = GetClassProperties<T>();
var results = new List<T>();
for (int x = 1; x<=100; x++)
{
var row = new T();
//Simulated Datasource
var dataSource = new Dictionary<string, object>();
dataSource.Add("one", x);
dataSource.Add("two", x.ToString());
dataSource.Add("item1", x);
dataSource.Add("item2", x+x);
dataSource.Add("item3", x*x);
foreach (var property in properties)
{
//this line executes the Action
property.Value(row, dataSource[property.Key]);
}
results.Add(row);
}
return results;
}
private static Dictionary<string, Action<T, object>> GetClassProperties<T>()
{
var setters = new Dictionary<string, Action<T, object>>();
var instance = Expression.Parameter(typeof(T));
var argument = Expression.Parameter(typeof(object));
foreach (var property in typeof(T).GetProperties())
{
var names = property.GetCustomAttributes(typeof(MapToAttribute), true)
.Select(p => ((MapToAttribute)p).Field);
var setter = Expression.Lambda<Action<T, object>>(
Expression.Call(
instance,
property.GetSetMethod(),
Expression.Convert(argument, property.PropertyType)
), instance, argument
).Compile();
// Due to the types I cannot just assign a value to a ICollection,
// that's why I tried to create HERE a different setter
// when the property Type is ICollection, I commented out the code failing.
//var getCollection = Expression.Lambda<Func<T, object>>(
// Expression.Call(
// instance,
// prop.GetGetMethod()
// ), instance
// ).Compile();
//Action<T, object> setter = (classInstance, value) =>
// getCollection(classInstance).Add(value);
foreach (var name in names)
{
setters.Add(name, setter);
}
}
return setters;
}
}
First of all to make life easier you will need to initialize collection:
public ICollection<int> collection { get; set; } = new List<int>();
Second try this:
private static Dictionary<string, Action<T, object>> GetClassProperties<T>()
{
var setters = new Dictionary<string, Action<T, object>>();
var instance = Expression.Parameter(typeof(T));
var argument = Expression.Parameter(typeof(object));
foreach (var property in typeof(T).GetProperties())
{
var names = property.GetCustomAttributes(typeof(MapToAttribute), true)
.Select(p => ((MapToAttribute)p).Field)
.ToList();
if (property.PropertyType.IsGenericType) // start checking that prop implements ICollection
{
// get ICollection generic parameter type
var genericParam = property.PropertyType.GetGenericArguments().First();
// construct concrete ICollection type
var propColType = typeof(ICollection<>).MakeGenericType(genericParam);
if (propColType.IsAssignableFrom(property.PropertyType)) // check if is ICollection of genericParam
{
var getCollection = Expression.Call(instance, property.GetGetMethod());
var addMethod = propColType.GetMethod("Add");
var colAddSetter = Expression.Lambda<Action<T, object>>(
Expression.Call(getCollection, addMethod, Expression.Convert(argument, genericParam)),
instance, argument)
.Compile();
foreach (var name in names)
{
setters.Add(name, colAddSetter);
}
continue; // process next property
}
}
// process "ordinary" property
var setter = Expression.Lambda<Action<T, object>>(
Expression.Call(
instance,
property.GetSetMethod(),
Expression.Convert(argument, property.PropertyType)
), instance, argument
).Compile();
setters.Add(names.Single(), setter); // todo throw normal exception instead of Single
}
return setters;
}
I want to get a list of each object from my List<T> (except strings, ints etc). And then Invoke (generic, recursive method with reflection). The problem is I am iterating on the property names, and have no idea how to select.
Error CS0021 Cannot apply indexing with [] to an expression of type 'T'
Code:
public static void My method<T>(IEnumerable<T> query)
{
var t = typeof(T);
var Headings = t.GetProperties();
for (int i = iteratorStart; i < Headings.Count(); i++)
{
if (IsValue(Headings[i].PropertyType.FullName))
{
}
else
{
Type type = Type.GetType(Headings[i].PropertyType.FullName);
var mi = typeof(ExcelExtension);
var met = mi.GetMethod("ListToExcel");
var genMet = met.MakeGenericMethod(type);
var nested = query.Select(p => p[Headings[i].Name]);
object[] parametersArray = new object[] { pck, nested, i };
genMet.Invoke(null, parametersArray);
}
}
}
As far as I can see, this is what you want:
public static void Mymethod<T>(IEnumerable<T> query)
{
var t = typeof(T);
int pck = 1234;
var mi = typeof(ExcelExtension);
var met = mi.GetMethod("ListToExcel");
var Headings = t.GetProperties();
for(int i=0; i < Headings.Length; ++i)
{
var prop = Headings[i];
if (prop.PropertyType.IsClass)
{
var genMet = met.MakeGenericMethod(prop.PropertyType);
var nested = query.Select(p => prop.GetValue(p));
object[] parametersArray = new object[] { pck, nested, i };
genMet.Invoke(null, parametersArray);
}
}
}
class ExcelExtension
{
public void ListToExcel<T>(int pck, IEnumerable<object> nested, int i)
{
}
}
Assuming you are using c# 6.0 or higher. You can use generic type parameters like;
public static void MyMethod<T>(IEnumerable<T> query) where T : IList
{
//Your code here
}
This way, you ensure that T is List of something and reaching indexing won't be a problem.
UPDATE
I misunderstood the question earlier. Here is the updated solution.
public static void MyMethod<T>(IEnumerable<T> query)
{
var t = typeof(T);
var Headings = t.GetProperties();
for (int i = iteratorStart; i < Headings.Count(); i++)
{
if (false == IsValue(Headings[i].PropertyType.FullName))
{
Type type = Type.GetType(Headings[i].PropertyType.FullName);
var mi = typeof(ExcelExtension);
var met = mi.GetMethod("ListToExcel");
var genMet = met.MakeGenericMethod(type);
//Assuming you want to get property value here. IF not You can use like Headings[i].GetName
var nested = query.Select(p =>Convert.ChangeType( Headings[i].GetValue(p),Headings[i].GetType()));
object[] parametersArray = new object[] { pck, nested, i };
genMet.Invoke(null, parametersArray);
}
}
}
Error Explanation:
The problem is in the Select(p => p[something here]) part. Since p is not the property list or array but a type of object, it doesn't contain any indexer. You should use reflection like above example.
I have a generic list of objects in C#, and wish to clone the list. The items within the list are cloneable, but there doesn't seem to be an option to do list.Clone().
Is there an easy way around this?
If your elements are value types, then you can just do:
List<YourType> newList = new List<YourType>(oldList);
However, if they are reference types and you want a deep copy (assuming your elements properly implement ICloneable), you could do something like this:
List<ICloneable> oldList = new List<ICloneable>();
List<ICloneable> newList = new List<ICloneable>(oldList.Count);
oldList.ForEach((item) =>
{
newList.Add((ICloneable)item.Clone());
});
Obviously, replace ICloneable in the above generics and cast with whatever your element type is that implements ICloneable.
If your element type doesn't support ICloneable but does have a copy-constructor, you could do this instead:
List<YourType> oldList = new List<YourType>();
List<YourType> newList = new List<YourType>(oldList.Count);
oldList.ForEach((item)=>
{
newList.Add(new YourType(item));
});
Personally, I would avoid ICloneable because of the need to guarantee a deep copy of all members. Instead, I'd suggest the copy-constructor or a factory method like YourType.CopyFrom(YourType itemToCopy) that returns a new instance of YourType.
Any of these options could be wrapped by a method (extension or otherwise).
You can use an extension method.
static class Extensions
{
public static IList<T> Clone<T>(this IList<T> listToClone) where T: ICloneable
{
return listToClone.Select(item => (T)item.Clone()).ToList();
}
}
For a shallow copy, you can instead use the GetRange method of the generic List class.
List<int> oldList = new List<int>( );
// Populate oldList...
List<int> newList = oldList.GetRange(0, oldList.Count);
Quoted from: Generics Recipes
public static object DeepClone(object obj)
{
object objResult = null;
using (var ms = new MemoryStream())
{
var bf = new BinaryFormatter();
bf.Serialize(ms, obj);
ms.Position = 0;
objResult = bf.Deserialize(ms);
}
return objResult;
}
This is one way to do it with C# and .NET 2.0. Your object requires to be [Serializable()]. The goal is to lose all references and build new ones.
To clone a list just call .ToList(). This creates a shallow copy.
Microsoft (R) Roslyn C# Compiler version 2.3.2.62116
Loading context from 'CSharpInteractive.rsp'.
Type "#help" for more information.
> var x = new List<int>() { 3, 4 };
> var y = x.ToList();
> x.Add(5)
> x
List<int>(3) { 3, 4, 5 }
> y
List<int>(2) { 3, 4 }
>
After a slight modification you can also clone:
public static T DeepClone<T>(T obj)
{
T objResult;
using (MemoryStream ms = new MemoryStream())
{
BinaryFormatter bf = new BinaryFormatter();
bf.Serialize(ms, obj);
ms.Position = 0;
objResult = (T)bf.Deserialize(ms);
}
return objResult;
}
Unless you need an actual clone of every single object inside your List<T>, the best way to clone a list is to create a new list with the old list as the collection parameter.
List<T> myList = ...;
List<T> cloneOfMyList = new List<T>(myList);
Changes to myList such as insert or remove will not affect cloneOfMyList and vice versa.
The actual objects the two Lists contain are still the same however.
Use AutoMapper (or whatever mapping lib you prefer) to clone is simple and a lot maintainable.
Define your mapping:
Mapper.CreateMap<YourType, YourType>();
Do the magic:
YourTypeList.ConvertAll(Mapper.Map<YourType, YourType>);
If you only care about value types...
And you know the type:
List<int> newList = new List<int>(oldList);
If you don't know the type before, you'll need a helper function:
List<T> Clone<T>(IEnumerable<T> oldList)
{
return newList = new List<T>(oldList);
}
The just:
List<string> myNewList = Clone(myOldList);
If you have already referenced Newtonsoft.Json in your project and your objects are serializeable you could always use:
List<T> newList = JsonConvert.DeserializeObject<T>(JsonConvert.SerializeObject(listToCopy))
Possibly not the most efficient way to do it, but unless you're doing it 100s of 1000s of times you may not even notice the speed difference.
For a deep copy, ICloneable is the correct solution, but here's a similar approach to ICloneable using the constructor instead of the ICloneable interface.
public class Student
{
public Student(Student student)
{
FirstName = student.FirstName;
LastName = student.LastName;
}
public string FirstName { get; set; }
public string LastName { get; set; }
}
// wherever you have the list
List<Student> students;
// and then where you want to make a copy
List<Student> copy = students.Select(s => new Student(s)).ToList();
you'll need the following library where you make the copy
using System.Linq
you could also use a for loop instead of System.Linq, but Linq makes it concise and clean. Likewise you could do as other answers have suggested and make extension methods, etc., but none of that is necessary.
There is no need to flag classes as Serializable and in our tests using the Newtonsoft JsonSerializer even faster than using BinaryFormatter. With extension methods usable on every object.
attention: private members are not cloned
Standard .NET JavascriptSerializer option:
public static T DeepCopy<T>(this T value)
{
JavaScriptSerializer js = new JavaScriptSerializer();
string json = js.Serialize(value);
return js.Deserialize<T>(json);
}
Faster option using Newtonsoft JSON:
public static T DeepCopy<T>(this T value)
{
string json = JsonConvert.SerializeObject(value);
return JsonConvert.DeserializeObject<T>(json);
}
I'll be lucky if anybody ever reads this... but in order to not return a list of type object in my Clone methods, I created an interface:
public interface IMyCloneable<T>
{
T Clone();
}
Then I specified the extension:
public static List<T> Clone<T>(this List<T> listToClone) where T : IMyCloneable<T>
{
return listToClone.Select(item => (T)item.Clone()).ToList();
}
And here is an implementation of the interface in my A/V marking software. I wanted to have my Clone() method return a list of VidMark (while the ICloneable interface wanted my method to return a list of object):
public class VidMark : IMyCloneable<VidMark>
{
public long Beg { get; set; }
public long End { get; set; }
public string Desc { get; set; }
public int Rank { get; set; } = 0;
public VidMark Clone()
{
return (VidMark)this.MemberwiseClone();
}
}
And finally, the usage of the extension inside a class:
private List<VidMark> _VidMarks;
private List<VidMark> _UndoVidMarks;
//Other methods instantiate and fill the lists
private void SetUndoVidMarks()
{
_UndoVidMarks = _VidMarks.Clone();
}
Anybody like it? Any improvements?
public static Object CloneType(Object objtype)
{
Object lstfinal = new Object();
using (MemoryStream memStream = new MemoryStream())
{
BinaryFormatter binaryFormatter = new BinaryFormatter(null, new StreamingContext(StreamingContextStates.Clone));
binaryFormatter.Serialize(memStream, objtype); memStream.Seek(0, SeekOrigin.Begin);
lstfinal = binaryFormatter.Deserialize(memStream);
}
return lstfinal;
}
public class CloneableList<T> : List<T>, ICloneable where T : ICloneable
{
public object Clone()
{
var clone = new List<T>();
ForEach(item => clone.Add((T)item.Clone()));
return clone;
}
}
public List<TEntity> Clone<TEntity>(List<TEntity> o1List) where TEntity : class , new()
{
List<TEntity> retList = new List<TEntity>();
try
{
Type sourceType = typeof(TEntity);
foreach(var o1 in o1List)
{
TEntity o2 = new TEntity();
foreach (PropertyInfo propInfo in (sourceType.GetProperties()))
{
var val = propInfo.GetValue(o1, null);
propInfo.SetValue(o2, val);
}
retList.Add(o2);
}
return retList;
}
catch
{
return retList;
}
}
If you need a cloned list with the same capacity, you can try this:
public static List<T> Clone<T>(this List<T> oldList)
{
var newList = new List<T>(oldList.Capacity);
newList.AddRange(oldList);
return newList;
}
//try this
List<string> ListCopy= new List<string>(OldList);
//or try
List<T> ListCopy=OldList.ToList();
If I need deep copy of collection, I have favorite approach like this:
public static IEnumerable<T> DeepCopy<T>(this IEnumerable<T> collectionToDeepCopy)
{
var serializedCollection = JsonConvert.SerializeObject(collectionToDeepCopy);
return JsonConvert.DeserializeObject<IEnumerable<T>>(serializedCollection);
}
You can use extension method:
namespace extension
{
public class ext
{
public static List<double> clone(this List<double> t)
{
List<double> kop = new List<double>();
int x;
for (x = 0; x < t.Count; x++)
{
kop.Add(t[x]);
}
return kop;
}
};
}
You can clone all objects by using their value type members for example, consider this class:
public class matrix
{
public List<List<double>> mat;
public int rows,cols;
public matrix clone()
{
// create new object
matrix copy = new matrix();
// firstly I can directly copy rows and cols because they are value types
copy.rows = this.rows;
copy.cols = this.cols;
// but now I can no t directly copy mat because it is not value type so
int x;
// I assume I have clone method for List<double>
for(x=0;x<this.mat.count;x++)
{
copy.mat.Add(this.mat[x].clone());
}
// then mat is cloned
return copy; // and copy of original is returned
}
};
Note: if you do any change on copy (or clone) it will not affect the original object.
Using a cast may be helpful, in this case, for a shallow copy:
IList CloneList(IList list)
{
IList result;
result = (IList)Activator.CreateInstance(list.GetType());
foreach (object item in list) result.Add(item);
return result;
}
applied to generic list:
List<T> Clone<T>(List<T> argument) => (List<T>)CloneList(argument);
I use automapper to copy an object. I just setup a mapping that maps one object to itself. You can wrap this operation any way you like.
http://automapper.codeplex.com/
I've made for my own some extension which converts ICollection of items that not implement IClonable
static class CollectionExtensions
{
public static ICollection<T> Clone<T>(this ICollection<T> listToClone)
{
var array = new T[listToClone.Count];
listToClone.CopyTo(array,0);
return array.ToList();
}
}
You could also simply convert the list to an array using ToArray, and then clone the array using Array.Clone(...).
Depending on your needs, the methods included in the Array class could meet your needs.
The following code should transfer onto a list with minimal changes.
Basically it works by inserting a new random number from a greater range with each successive loop. If there exist numbers already that are the same or higher than it, shift those random numbers up one so they transfer into the new larger range of random indexes.
// Example Usage
int[] indexes = getRandomUniqueIndexArray(selectFrom.Length, toSet.Length);
for(int i = 0; i < toSet.Length; i++)
toSet[i] = selectFrom[indexes[i]];
private int[] getRandomUniqueIndexArray(int length, int count)
{
if(count > length || count < 1 || length < 1)
return new int[0];
int[] toReturn = new int[count];
if(count == length)
{
for(int i = 0; i < toReturn.Length; i++) toReturn[i] = i;
return toReturn;
}
Random r = new Random();
int startPos = count - 1;
for(int i = startPos; i >= 0; i--)
{
int index = r.Next(length - i);
for(int j = startPos; j > i; j--)
if(toReturn[j] >= index)
toReturn[j]++;
toReturn[i] = index;
}
return toReturn;
}
Another thing: you could use reflection. If you'll cache this properly, then it'll clone 1,000,000 objects in 5.6 seconds (sadly, 16.4 seconds with inner objects).
[ProtoContract(ImplicitFields = ImplicitFields.AllPublic)]
public class Person
{
...
Job JobDescription
...
}
[ProtoContract(ImplicitFields = ImplicitFields.AllPublic)]
public class Job
{...
}
private static readonly Type stringType = typeof (string);
public static class CopyFactory
{
static readonly Dictionary<Type, PropertyInfo[]> ProperyList = new Dictionary<Type, PropertyInfo[]>();
private static readonly MethodInfo CreateCopyReflectionMethod;
static CopyFactory()
{
CreateCopyReflectionMethod = typeof(CopyFactory).GetMethod("CreateCopyReflection", BindingFlags.Static | BindingFlags.Public);
}
public static T CreateCopyReflection<T>(T source) where T : new()
{
var copyInstance = new T();
var sourceType = typeof(T);
PropertyInfo[] propList;
if (ProperyList.ContainsKey(sourceType))
propList = ProperyList[sourceType];
else
{
propList = sourceType.GetProperties(BindingFlags.Public | BindingFlags.Instance);
ProperyList.Add(sourceType, propList);
}
foreach (var prop in propList)
{
var value = prop.GetValue(source, null);
prop.SetValue(copyInstance,
value != null && prop.PropertyType.IsClass && prop.PropertyType != stringType ? CreateCopyReflectionMethod.MakeGenericMethod(prop.PropertyType).Invoke(null, new object[] { value }) : value, null);
}
return copyInstance;
}
I measured it in a simple way, by using the Watcher class.
var person = new Person
{
...
};
for (var i = 0; i < 1000000; i++)
{
personList.Add(person);
}
var watcher = new Stopwatch();
watcher.Start();
var copylist = personList.Select(CopyFactory.CreateCopyReflection).ToList();
watcher.Stop();
var elapsed = watcher.Elapsed;
RESULT: With inner object PersonInstance - 16.4, PersonInstance = null - 5.6
CopyFactory is just my test class where I have dozen of tests including usage of expression. You could implement this in another form in an extension or whatever. Don't forget about caching.
I didn't test serializing yet, but I doubt in an improvement with a million classes. I'll try something fast protobuf/newton.
P.S.: for the sake of reading simplicity, I only used auto-property here. I could update with FieldInfo, or you should easily implement this by your own.
I recently tested the Protocol Buffers serializer with the DeepClone function out of the box. It wins with 4.2 seconds on a million simple objects, but when it comes to inner objects, it wins with the result 7.4 seconds.
Serializer.DeepClone(personList);
SUMMARY: If you don't have access to the classes, then this will help. Otherwise it depends on the count of the objects. I think you could use reflection up to 10,000 objects (maybe a bit less), but for more than this the Protocol Buffers serializer will perform better.
There is a simple way to clone objects in C# using a JSON serializer and deserializer.
You can create an extension class:
using Newtonsoft.Json;
static class typeExtensions
{
[Extension()]
public static T jsonCloneObject<T>(T source)
{
string json = JsonConvert.SerializeObject(source);
return JsonConvert.DeserializeObject<T>(json);
}
}
To clone and object:
obj clonedObj = originalObj.jsonCloneObject;
For a deep clone I use reflection as follows:
public List<T> CloneList<T>(IEnumerable<T> listToClone) {
Type listType = listToClone.GetType();
Type elementType = listType.GetGenericArguments()[0];
List<T> listCopy = new List<T>();
foreach (T item in listToClone) {
object itemCopy = Activator.CreateInstance(elementType);
foreach (PropertyInfo property in elementType.GetProperties()) {
elementType.GetProperty(property.Name).SetValue(itemCopy, property.GetValue(item));
}
listCopy.Add((T)itemCopy);
}
return listCopy;
}
You can use List or IEnumerable interchangeably.
You can use the List<T>.ConvertAll(Converter<T, T>) method to create a new list containing all the elements of the original list, and use a conversion function that returns the input value.
List<int> originalList = new List<int> { 1, 2, 3, 4, 5 };
List<int> clonedList = new List<int>(originalList.ConvertAll(x => x));
I use XML serialization for the reading of my Config-POCOs.
To get intellisense support in Visual Studio for XML files I need a schema file. I can create the schema with xsd.exe mylibrary.dll and this works fine.
But I want that the schema is always created if I serialize an object to the file system. Is there any way without using xsd.exe?
thank you, this was the right way for me.
solution:
XmlReflectionImporter importer = new XmlReflectionImporter();
XmlSchemas schemas = new XmlSchemas();
XmlSchemaExporter exporter = new XmlSchemaExporter(schemas);
Type type = toSerialize.GetType();
XmlTypeMapping map = importer.ImportTypeMapping(type);
exporter.ExportTypeMapping(map);
TextWriter tw = new StreamWriter(fileName + ".xsd");
schemas[0].Write(tw);
tw.Close();
The solution posted above by Will worked wonderfully, except I realized that the schema generated did not reflect the attributes on the different class members. For example a class decorated with serialization hint attributes (see the sample below), would have not rendered correctly.
public class Test
{
[XmlAttribute()]
public string Attribute { get; set; }
public string Description { get; set; }
[XmlArray(ElementName = "Customers")]
[XmlArrayItem(ElementName = "Customer")]
public List<CustomerClass> blah { get; set; }
}
To address this, I created a few helper functions that use reflection to traverse the class hierarchy, read the attributes, and populate a XmlAttributeOverrides object that can be passed into the XmlReflectionImporter.
public static void AttachXmlAttributes(XmlAttributeOverrides xao, Type t)
{
List<Type> types = new List<Type>();
AttachXmlAttributes(xao, types, t);
}
public static void AttachXmlAttributes(XmlAttributeOverrides xao, List<Type> all, Type t)
{
if(all.Contains(t))
return;
else
all.Add(t);
XmlAttributes list1 = GetAttributeList(t.GetCustomAttributes(false));
xao.Add(t, list1);
foreach (var prop in t.GetProperties())
{
XmlAttributes list2 = GetAttributeList(prop.GetCustomAttributes(false));
xao.Add(t, prop.Name, list2);
AttachXmlAttributes(xao, all, prop.PropertyType);
}
}
private static XmlAttributes GetAttributeList(object[] attributes)
{
XmlAttributes list = new XmlAttributes();
foreach (var attribute in attributes)
{
Type type = attribute.GetType();
if (type.Name == "XmlAttributeAttribute") list.XmlAttribute = (XmlAttributeAttribute)attribute;
else if (type.Name == "XmlArrayAttribute") list.XmlArray = (XmlArrayAttribute)attribute;
else if (type.Name == "XmlArrayItemAttribute") list.XmlArrayItems.Add((XmlArrayItemAttribute)attribute);
}
return list;
}
public static string GetSchema<T>()
{
XmlAttributeOverrides xao = new XmlAttributeOverrides();
AttachXmlAttributes(xao, typeof(T));
XmlReflectionImporter importer = new XmlReflectionImporter(xao);
XmlSchemas schemas = new XmlSchemas();
XmlSchemaExporter exporter = new XmlSchemaExporter(schemas);
XmlTypeMapping map = importer.ImportTypeMapping(typeof(T));
exporter.ExportTypeMapping(map);
using (MemoryStream ms = new MemoryStream())
{
schemas[0].Write(ms);
ms.Position = 0;
return new StreamReader(ms).ReadToEnd();
}
}
Hope this helps someone else.
Look at the System.Xml.Serialization.XmlSchemaExporter class. I can't recall the exact details, but there is enough functionality in that namespace to do what you require.
Improvement to Matt Murrell version: to apply XmlAttributes recursively for nested property user type (for example CustomerClass property).
private static void AttachXmlAttributes(XmlAttributeOverrides xao, List<Type> all, Type t)
{
if (all.Contains(t))
{
return;
}
else
{
all.Add(t);
}
var list1 = GetAttributeList(t.GetCustomAttributes(false));
xao.Add(t, list1);
foreach (var prop in t.GetProperties())
{
var propType = prop.PropertyType;
if (propType.IsGenericType) // is list?
{
var args = propType.GetGenericArguments();
if (args != null && args.Length == 1)
{
var genType = args[0];
if (genType.Name.ToLower() != "object")
{
var list2 = GetAttributeList(prop.GetCustomAttributes(false));
xao.Add(t, prop.Name, list2);
AttachXmlAttributes(xao, all, genType);
}
}
}
else
{
var list2 = GetAttributeList(prop.GetCustomAttributes(false));
xao.Add(t, prop.Name, list2);
AttachXmlAttributes(xao, all, prop.PropertyType);
}
}
}
private static XmlAttributes GetAttributeList(object[] attributes)
{
var list = new XmlAttributes();
foreach (var attr in attributes)
{
Type type = attr.GetType();
switch (type.Name)
{
case "XmlAttributeAttribute":
list.XmlAttribute = (XmlAttributeAttribute)attr;
break;
case "XmlRootAttribute":
list.XmlRoot = (XmlRootAttribute)attr;
break;
case "XmlElementAttribute":
list.XmlElements.Add((XmlElementAttribute)attr);
break;
case "XmlArrayAttribute":
list.XmlArray = (XmlArrayAttribute)attr;
break;
case "XmlArrayItemAttribute":
list.XmlArrayItems.Add((XmlArrayItemAttribute)attr);
break;
}
}
return list;
}