How to create a property for a List T

Question

private List lt T gt  newList   public List lt T gt  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 lt KeyValuePair lt string  string gt  gt   settings   public List lt KeyValuePair lt string  string gt  gt  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 lt Options gt  userOptions   new List lt Options gt               public int ID                       get   return userId                set   user   userId                       public string Pass                       get   return pass                set   pass   value                       public List lt Options gt  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

User · Answer

It s possible to have a property of type List lt T gt  but your class needs to be passed the T too   public class ClassName lt T gt      public List lt T gt  MyProperty   get  set

User · Answer

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 lt T gt      etc

User · Answer

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 lt T gt        private List lt T gt  newList       public List lt T gt  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 lt int gt  newList   public List lt int gt  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 lt KeyValuePair lt string  string gt  gt  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 lt KeyValuePair lt string  string gt  MySettings   get  set        public class MyConsumingClass       public void MyMethod               MyClass myClass   new MyClass            myClass MySettings   new List lt KeyValuePair lt string  string gt  gt             myClass MySettings Add new KeyValuePair lt string  string gt   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

User · Answer

You could do this but the T generic parameter needs to be declared at the containing class   public class Foo lt T gt        public List lt T gt  NewList   get  set

User · Answer

Simple and effective alternative   public class ClassName       public List lt dynamic gt  MyProperty   get  set        or  public class ClassName       public List lt object gt  MyProperty   get  set        For differences see this post  List lt Object gt  vs List lt dynamic gt

User · Answer

public class MyClass lt T gt      private List lt T gt  list     public List lt T gt  MyList   get   return list    set   list   value          Then you can do something like   MyClass lt int gt  instance1   new MyClass lt int gt     List lt int gt  integers   instance1 MyList   MyClass lt Person gt  instance2   new MyClass lt Person gt     IEnumerable lt Person gt  persons   instance2 MyList

[c#] How to create a property for a List<T>

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