Serialise object state to const C# class

Question

A couple of times, i've found myself wanting to take the state of an object, and make it into a constant. Eg. I'm designing a UI, that displays informatation from say a database call. and I just want a sample of the data to play around with, so i can see what everything would look like.

Let say I have:

public interface IPerson
{
   string Name{get;}
   string Age {get;}
   ...
}

public class Person
{
   string Name{get; set}
   string Age {get; set}
   ...

}

and some method that does say the database call, or what ever to load it. For this example lets say for simpicities sake it loads it from a CSV file: for this example the file contains: "Mrs McKenzy, 56,.."

IPerson Load(string fileName)
{
    var text = File.ReadAllText(filename);
    var parts = text.Split(",");
    return new Person()
    {
        Name = parts[0],
        Age = Int32.Parse(parts[1]),
        ...
    }
}

from this I want to generate my sample class: (as a .cs file)

public class SamplePerson : IPerson
{
    string Name{get {return "Mrs McKenzy"}}
    string Age {get {return 56}}
    ...  
}

The only way I can see of doing this is serialise the object (prob to XML, so i can see what is in it), and then have my SamplePerson deserialise the object in its constructor, to intitialise itself. Now this isn't a bad solution. But I figure it would be nicer if I could just "Serialise to C#". Seems like something that could be put together without too much trouble with reflection, so I'm wondering if there is some existing library for it. (If not I guess it could be a fun project if ever I get bord)

Answer 1

Perhaps you can abstract the mechanism to an interface, something like:

public interface IPersonRepository
{
  IPerson GetPerson(int id);
}

And provide a design-time implementation.

public class DesignTimePersonRepository : IPersonRepository
{
  public IPerson GetPerson(int id)
  {
    return new DesignTimePerson { Name = "Joe Bloggs", Age = 56 };
  }
}

Now, assuming you can determine whether you're in Design mode, or not, you could do something like:

public IPersonRepository GetPersonRepository()
{
  return DesignMode
    ? new DesignTimePersonRepository()
    : _container.Resolve<IPersonRepository>();
}

Answer 2

As I understand you want to save the object properties as a hard coded value. Why to do so?

According to your markup I can guess you wish to be able to get but not set the value. If this is a case you might use the following approach.

// make a public interface
public interface IPerson {
    String Name { get; }
    String Age { get; }
}

public class Manager {
    public IEnumerable<IPerson> GetPeople() {
        var retVal = new List<Person>();
        // Do your retrieval. Here you can access
        // the setters of your class. 
        return retVal;
    }
    // make a private implementation
    private class Person : IPerson {
        public String Name { get; set; }
        public String Age { get; set; }

        // explicit interface implementation
        String IPerson.Name {
            get { return Name; }
        }

        String IPerson.Age {
            get { return Age; }
        }
    }
}

This approach allows you to hide the actual implementation and restrict the access to the properties making them only readable.

Answer 3

How about this, using the CSharpCodeProvider, compile your class, then instance it and use dynamics.....

void Main()
{
    dynamic instanceOfMyType;

    using (CSharpCodeProvider csharpCodeProvider = new CSharpCodeProvider())
    {

        var outPutFile = Path.ChangeExtension(Path.GetTempFileName(), ".dll");
        CompilerParameters parameters = new CompilerParameters()
        {
            //For creating DLLs it should be false
            GenerateExecutable = false,
            OutputAssembly = outPutFile,
            //For displaying warnings in the compilerResults
            WarningLevel = 4,

        };
        //I am reading the text from a WPF RichTextbox
        var text = File.ReadAllText(@"c:\temp\SampleFoo.cs");
        CompilerResults compilerResults = csharpCodeProvider.CompileAssemblyFromSource(parameters, text);

        var type = compilerResults.CompiledAssembly.GetType("SampleFoo");
        instanceOfMyType = Activator.CreateInstance(type);
    }
    Console.WriteLine (instanceOfMyType.Bar);
}

* How to compile C# code snippet in runtime

---

or you can share the IPerson as a dll en the SamplePerson class.....

........