将匿名类型转换为类

Question

I got an anonymous type inside a List anBook:

var anBook=new []{

new {Code=10, Book ="Harry Potter"},
new {Code=11, Book="James Bond"}
};

Is to possible to convert it to a List with the following definition of clearBook:

public class ClearBook
{
  int Code;
  string Book; 
}

by using direct conversion, ie, without looping through anBook?

Answer 1

Well, you could use:

var list = anBook.Select(x => new ClearBook {
               Code = x.Code, Book = x.Book}).ToList();

but no, there is no direct conversion support. Obviously you'll need to add accessors, etc. (don't make the fields public) - I'd guess:

public int Code { get; set; }
public string Book { get; set; }

Of course, the other option is to start with the data how you want it:

var list = new List<ClearBook> {
    new ClearBook { Code=10, Book="Harry Potter" },
    new ClearBook { Code=11, Book="James Bond" }
};

There are also things you could do to map the data with reflection (perhaps using an Expression to compile and cache the strategy), but it probably isn't worth it.

Answer 2

As Marc says, it can be done with reflection and expression trees... and as luck would have it, there's a class in MiscUtil which does exactly that. However, looking at your question more closely it sounds like you want to apply this conversion to a collection (array, list or whatever) without looping . That can't possibly work. You're converting from one type to another - it's not like you can use a reference to the anonymous type as if it's a reference to ClearBook.

To give an example of how the PropertyCopy class works though, you'd just need:

var books = anBook.Select(book => PropertyCopy<ClearBook>.CopyFrom(book))
                                 .ToList();

Answer 3

What about these extension? simple call the .ToNonAnonymousList on your anonymous type..

public static object ToNonAnonymousList<T>(this List<T> list, Type t)
    {
        //define system Type representing List of objects of T type:
        Type genericType = typeof (List<>).MakeGenericType(t);

        //create an object instance of defined type:
        object l = Activator.CreateInstance(genericType);

        //get method Add from from the list:
        MethodInfo addMethod = l.GetType().GetMethod("Add");

        //loop through the calling list:
        foreach (T item in list)
        {
            //convert each object of the list into T object by calling extension ToType<T>()
            //Add this object to newly created list:
            addMethod.Invoke(l, new[] {item.ToType(t)});
        }
        //return List of T objects:
        return l;
    }
    public static object ToType<T>(this object obj, T type)
    {
        //create instance of T type object:
        object tmp = Activator.CreateInstance(Type.GetType(type.ToString()));

        //loop through the properties of the object you want to covert:          
        foreach (PropertyInfo pi in obj.GetType().GetProperties())
        {
            try
            {
                //get the value of property and try to assign it to the property of T type object:
                tmp.GetType().GetProperty(pi.Name).SetValue(tmp, pi.GetValue(obj, null), null);
            }
            catch (Exception ex)
            {
                Logging.Log.Error(ex);
            }
        }
        //return the T type object:         
        return tmp;
    }

Answer 4

The simplest way to do it could just be to use some type of serialization method.

something like along these lines

class ClearBook
{
   public int Code { get; set; }
   public string Book { get; set; }
}

ClearBook[] newList = JsonSerializer.Deserialize<ClearBook[]>(JsonSerializer.Serialize(anBook));