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I want to fill class members with default if they are missing, using generic in C#

I have multiple web requests that post JSON object and I have serializable classes with all the fields. For example:
[Serializable]
public class RequestOne()
{
public string date;
public string information;
public string subject;
}
[Serializable]
public class RequestTwo()
{
public int ID;
public string Data;
public string message;
}
And my method takes partially filled request class and I want to fill in any missing fields with default values declared in constant class.
And I want to avoid writing each method with for each request, like :
public static void FillWithDefault(this RequestOne request)
{ if (request.date.Equals(null)) request.date = DEFAULT_DATE;
if (request.information.Equals(null)) request.information = DEFAULT_INFO;
if (request.subject.Equals(null)) request.subject = DEFAULT_SUBJECT;
}
public static void FillWithDefault(this RequestTwo request)
{
//do the same for the fields in RequestTwo
}
I want to know if there is any way to achieve this using generic?
I want to do something similar to this:
public static void FillWithDefault<T>(this T request)
{
if(typeof(T) == typeof(request))
{
//check each member in request and fill with default if it's null
}
.
.
.
}
So that in my main method I can use like this :
RequestOne request = new RequestOne();
request.FillWithDefault();
RequestTwo request2 = new RequestTwo();
request2.FillWithDefault();
Can someone please help with idea on this? Am I overthinking on this? I'm new to generic so please feel free to advise on my code.
Edit
Sorry guys, I did not mention that I will be using this method for test automation. Those request contracts cannot be changed since it's by design. Sorry again for the confusion!

Use constructors. Also make use of properties. Don't gather the default filling code to one place, it's the responsibility of the classes so keep them there.
[Serializable]
public class RequestOne()
{
public string date { get; set; };
public string information { get; set; };
public string subject { get; set; };
public RequestOne()
{
Date = DEFAULT_DATE;
Information = DEFAULT_DATE;
Subject = DEFAULT_SUBJECT;
}
}
[Serializable]
public class RequestTwo()
{
public int ID { get; set; };
public string Data { get; set; };
public string Message { get; set; };
public RequestTwo()
{
Data = DEFAULT_DATA;
message = DEFAULT_MESSAGE;
}
}

Generics are used when the types have common operations/properties defined so you can apply the same routine for each type in one place instead of declaring different methods for each type.
However in this case, you have two different types with different properties, so I would not use generics here. You can achieve it with manual type checking and using reflection to get properties and set them but it's not a good way and definitely wouldn't be a good usage of generics.
Overloading is the way to go.

you can use property
[Serializable]
public class RequestOne()
{
private string _date;
public string date { get { return _date;} set { _date = value ?? DEFAULT_DATE; }};
public string information; // same here
public string subject; //same here
}

(C#) Access/Modify Objects in a List

New here, I've been learning c# for about a month.
Anyway, I've been searching StackOverflow for a couple of days now and couldn't find a specific answer to my problem...
//Here's my Class
public class Guy
{
public static int ID { get; set; }
public static int LifeExpectancy { get; set; }
public static bool Living { get; set; }
public Guy(int id, int lifeExpectancy, bool living)
{
ID = id;
LifeExpectancy = lifeExpectancy;
Living = living;
}
}
What I'm trying to do is create a specific number of "someGuy" objects to then put them into a public list using this method...
public static List<Guy> Guys = new List<Guy>();
public static void makeSomeGuys(int howManyGuys)
{
for (int i = 0, i <= howManyGuys; i++)
{
int id = i;
int lifeExpectancy = 80;
bool alive = true;
Guys.Add(New Guy(id, lifeExpectancy, alive));
Console.WriteLine("Made a new Guy {0}", id);
}
return;
}
Questions in order of importance:
How do I access a specific object as well as its parameters? (Accessing from the list "Guys".)
How do I access an object from this list in another class? (Not that I absolutely need to, I'm curious)
Can I search for an object in a list by using its parameters? (As opposed to doing something like... humanPopulation[number])
Should I create a new list for objects that have had their parameters modified? (As opposed to leaving it in the original list)
Is it possible to remove items from a list? (Just in general, is that a thing people do? if so, why?)
I really only need the first question answered. The rest of them are just a bonus. Thanks!

First you need to remove the static modifier from the properties of the Guy class, i.e.:
public int ID { get; set; }
public int LifeExpectancy { get; set; }
public bool Living { get; set; }
because static causes the property to be an attribute of the class itself, rather than the instances of the class (the individual 'guys').
To access life expectancy of the first guy (the zeroth):
Console.WriteLine(Guys[0].LifeExpectancy);
To access life expectancy of the fifth guy:
Console.WriteLine(Guys[4].LifeExpectancy);

using System;
using System.Collections.Generic;
using System.Linq;
namespace test
{
public class Guy
{
private int m_ID;
private int m_LifeExpectancy;
private bool m_Living;
public int ID
{
get { return m_ID; }
set { m_ID = value; }
}
public int LifeExpectancy
{
get { return m_LifeExpectancy; }
set { m_LifeExpectancy = value; }
}
public bool Living
{
get { return m_Living; }
set { m_Living = value; }
}
public Guy(int id, int lifeExpectancy, bool living)
{
ID = id;
LifeExpectancy = lifeExpectancy;
Living = living;
}
}
public class MyFactory
{
public IList<Guy> MakeSomeGuys(int howManyGuys)
{
IList<Guy> localGuys = new List<Guy>();
for (int i = 0; i <= howManyGuys; i++)
{
int id = i;
int lifeExpectancy = 80;
bool alive = true;
localGuys.Add(new Guy(id, lifeExpectancy, alive));
Console.WriteLine("Made a new Guy {0}", id);
}
return localGuys;
}
}
public class program
{
public void Main()
{
MyFactory mf = new MyFactory();
IList<Guy> guys = mf.MakeSomeGuys(5);
//How do I access a specific object as well as its parameters? (Accessing from the list "Guys".)
int GetFirstGuyId = guys.FirstOrDefault().ID; //LEARN LINQ
//How do I access an object from this list in another class? (Not that I absolutely need to, I'm curious)
//you need to learn about object oriented encapsulation for better understanding.
//Can I search for an object in a list by using its parameters? (As opposed to doing something like...humanPopulation[number])
Guy guyById = guys.Where(g => g.ID == 5).FirstOrDefault(); // returns the first match (need to learn lambda expression)
//Should I create a new list for objects that have had their parameters modified? (As opposed to leaving it in the original list)
// you need to learn about passing values by value / reference (by reference you already changing the original!).
//Is it possible to remove items from a list? (Just in general, is that a thing people do? if so, why?)
//yes
guys.Remove(guyById);
}
}
}

You're likely new to C# and OO programming, so I've included some good links in this answer.
Regarding question 1 only:
Firstly, your Guy class properties aren't properly encapsulated. Make sure you properly scope the ID, LifeExpectancy and Living properties like shown in this article.
If you'd like to access a specific item, that is, a Guy with a particular ID, you'd be better off using an associative container like Dictionary.
If you're happy with the List container, you need to use the Find method on Guys as shown in the example at the link. You'll notice the term Predicate in the documentation, this link will elaborate.

How to compare objects in C#

How do you compare objects in C#. Here is a sample of my code
namespace MyService
{
public static class CurrentVCobj
{
public static string id { get; set; }
public static string Month { get; set; }
public static string Year { get; set; }
}
public static class ResponseVCObj
{
public static string id { get; set; }
public static string Month { get; set; }
public static string Year { get; set; }
}
}
I would like to assign values to the above objects (CurrentVCobj and ResponseVCObj) then compare(TRUE OR FALSE) them in the method below to see if they are equal
public static void compareMethood(IEnumerable<tets> vc )
{
var myvar = vc;
var mycac = rep.populateDict();
foreach (var item in myvar)
{
ResponseVCObj.id = item.id;
ResponseVCObj.Month = DateRange.Month;
ResponseVCObj.Year = DateRange.Year;
CurrentVCobj.id = currentV.Select(d => d.Value.id).ToString() ;
CurrentVCobj.Month = currentV.Select(d => d.Value.Month).ToString();
CurrentVCobj.Year = currentV.Select(d => d.Value.Year).ToString();
//COMPARE OBJECTS HERE
}
}

Try this:
if (ResponseVCObj.Equals(CurrentVCobj))
{
...
}
else
{
...
}

First off, is there any reason you are using static classes? Your sample code seems very bizarre to me. Your usage of LINQ seems unnecessary as well.
If you want to compare two different objects by something other than a simple reference check you need to override the Equals method.
A guide on that can be found here:
http://msdn.microsoft.com/en-us/library/ms173147(v=vs.80).aspx

The other answers are correct in noting that you should override object.Equals, and that you should remove the static modifier from the classes and their members.
In addition, you should consider
having the classes inherit from the same interface
having the classes inherit from the same base class; if this is possible, then you can implement the equality comparison in that base class
implementing IEquatable on each class or the base class; if there's no common base type then you probably want to implement it twice on each type -- IEnumerable<CurrentVCobj> and IEnumerable<ResponseVCObj>
the fact that when you compare strings for equality, the results may vary from one computer to the other, depending on the culture settings on that computer.

System.Reflection GetProperties method not returning values

Can some one explain to me why the GetProperties method would not return public values if the class is setup as follows.
public class DocumentA
{
public string AgencyNumber = string.Empty;
public bool Description;
public bool Establishment;
}
I am trying to setup a simple unit test method to play around with
The method is as follows and it has all the appropriate using statements and references.
All I'm doing is calling the following but it returns 0
PropertyInfo[] pi = target.GetProperties(BindingFlags.Public | BindingFlags.Instance);
But if I setup the class with private members and public properties it works fine.
The reason I didn't setup up the the class the old school way was because it has 61 properties and doing that would increase my lines of code to at least triple that. I would be a maintenance nightmare.

You haven't declared any properties - you've declared fields. Here's similar code with properties:
public class DocumentA
{
public string AgencyNumber { get; set; }
public bool Description { get; set; }
public bool Establishment { get; set; }
public DocumentA()
{
AgencyNumber = "";
}
}
I would strongly advise you to use properties as above (or possibly with more restricted setters) instead of just changing to use Type.GetFields. Public fields violate encapsulation. (Public mutable properties aren't great on the encapsulation front, but at least they give an API, the implementation of which can be changed later.)

Because the way you have declared your class now is using Fields. If you want to access the fields trough reflection you should use Type.GetFields() (see Types.GetFields Method1)
I don't now which version of C# you're using but the property syntax has changed in C# 2 to the following:
public class Foo
{
public string MyField;
public string MyProperty {get;set;}
}
Wouldn't this help in reducing the amount of code?

I see this thread is already four years old, but none the less I was unsatisfied with the answers provided. OP should note that OP is referring to Fields not Properties. To dynamically reset all fields (expansion proof) try:
/**
* method to iterate through Vehicle class fields (dynamic..)
* resets each field to null
**/
public void reset(){
try{
Type myType = this.GetType(); //get the type handle of a specified class
FieldInfo[] myfield = myType.GetFields(); //get the fields of the specified class
for (int pointer = 0; pointer < myfield.Length ; pointer++){
myfield[pointer].SetValue(this, null); //takes field from this instance and fills it with null
}
}
catch(Exception e){
Debug.Log (e.Message); //prints error message to terminal
}
}
Note that GetFields() only has access to public fields for obvious reasons.

As mentioned, these are fields not properties. The property syntax would be:
public class DocumentA {
public string AgencyNumber { get; set; }
public bool Description { get; set; }
public bool Establishment { get; set;}
}

How to create a property for a List<T>

private List<T> newList;
public List<T> NewList
{
get{return newList;}
set{newList = value;}
}
I want to create something like this, but this is won't work. it's just an example to demonstrate my goal as it's pretty common creating proprties for string and int and even T but I've never seen a List property
Is it even possible do such a thing, creating a property for type List ?
EDIT
I have a normal class that has normal properties (string properties, int properties, etc) but I have this property that stores user options, So on the presentation layer I had to convert them into a string so I could be able to store them in the Object. Now is it possible to have a property of type List to store the multivalues in a better and clean way, instead of converting information into one string and then split it and again join it! Thanks Again =D
EDIT2
private List<KeyValuePair<string, string>> _settings;
public List<KeyValuePair<string, string>> MySettings
{
get { return _settings; }
set { _settings = value; }
}
I used the exact code you posted but the property still won't appear in the object's instance, so I tried adding code in the get and set (I wonder why you left them empty or does it means something?) and also added a private variable in the class but still it doesn't appear in the properties of the object's instance!
I hope you could provide the exact code to implement this property and a simple code that assigns or retrieves from/to an instance of this class object
It's the first time to even hear about this KeyValuePair and all the tutorials are pretty simple and not for my case, sorry!
The Last Edit: After a lot of researching and the help of Mark Avenius I found the perfect answer. hope everyone can benefit from this.
NOW! HOW TO CREATE A PROPERTY FOR A LIST :
The Options Class
Public Class Options
{
private string id;
private int option;
public int ID
{
get { return id; }
set { id= value; }
}
public string Option
{
get { return option; }
set { option = value; }
}
}
The Users Class
public class Users
{
private int userId;
private string pass;
private List<Options> userOptions = new List<Options>();
public int ID
{
get { return userId; }
set { user = userId; }
}
public string Pass
{
get { return pass; }
set { pass = value; }
}
public List<Options> OptionsList
{
get { return userOptions; }
set { userOptions = value; }
}
}
The Presentation Layer
Users newUser = new Users ();
Options userOption = new Options ();
userOption.ID = int.Parse(txtBxID.Text);
userOption.Option = txtBxOption.Text;
Item.Options.Add(userOption);

T must be defined within the scope in which you are working. Therefore, what you have posted will work if your class is generic on T:
public class MyClass<T>
{
private List<T> newList;
public List<T> NewList
{
get{return newList;}
set{newList = value;}
}
}
Otherwise, you have to use a defined type.
EDIT: Per #lKashef's request, following is how to have a List property:
private List<int> newList;
public List<int> NewList
{
get{return newList;}
set{newList = value;}
}
This can go within a non-generic class.
Edit 2:
In response to your second question (in your edit), I would not recommend using a list for this type of data handling (if I am understanding you correctly). I would put the user settings in their own class (or struct, if you wish) and have a property of this type on your original class:
public class UserSettings
{
string FirstName { get; set; }
string LastName { get; set; }
// etc.
}
public class MyClass
{
string MyClassProperty1 { get; set; }
// etc.
UserSettings MySettings { get; set; }
}
This way, you have named properties that you can reference instead of an arbitrary index in a list. For example, you can reference MySettings.FirstName as opposed to MySettingsList[0].
Let me know if you have any further questions.
EDIT 3:
For the question in the comments, your property would be like this:
public class MyClass
{
public List<KeyValuePair<string, string>> MySettings { get; set; }
}
EDIT 4: Based on the question's edit 2, following is how I would use this:
public class MyClass
{
// note that this type of property declaration is called an "Automatic Property" and
// it means the same thing as you had written (the private backing variable is used behind the scenes, but you don't see it)
public List<KeyValuePair<string, string> MySettings { get; set; }
}
public class MyConsumingClass
{
public void MyMethod
{
MyClass myClass = new MyClass();
myClass.MySettings = new List<KeyValuePair<string, string>>();
myClass.MySettings.Add(new KeyValuePair<string, string>("SomeKeyValue", "SomeValue"));
// etc.
}
}
You mentioned that "the property still won't appear in the object's instance," and I am not sure what you mean. Does this property not appear in IntelliSense? Are you sure that you have created an instance of MyClass (like myClass.MySettings above), or are you trying to access it like a static property (like MyClass.MySettings)?

Simple and effective alternative:
public class ClassName
{
public List<dynamic> MyProperty { get; set; }
}
or
public class ClassName
{
public List<object> MyProperty { get; set; }
}
For differences see this post: List<Object> vs List<dynamic>

public class MyClass<T>
{
private List<T> list;
public List<T> MyList { get { return list; } set { list = value; } }
}
Then you can do something like
MyClass<int> instance1 = new MyClass<int>();
List<int> integers = instance1.MyList;
MyClass<Person> instance2 = new MyClass<Person>();
IEnumerable<Person> persons = instance2.MyList;

You could do this but the T generic parameter needs to be declared at the containing class:
public class Foo<T>
{
public List<T> NewList { get; set; }
}

It's possible to have a property of type List<T> but your class needs to be passed the T too.
public class ClassName<T>
{
public List<T> MyProperty { get; set; }
}

Either specify the type of T, or if you want to make it generic, you'll need to make the parent class generic.
public class MyClass<T>
{
etc