Ygthkb

I'm learning C# and a thought came up when coding. Is it possible to automaticly store parameters from a constructor to the fields in a simple way without having to write this.var = var on every variable to store them?

Example:

class MyClass

{

    int var1;

    int var2;

    int var3;

    int var4;

    public MyClass(int var1, int var2, int var3, int var4){

        this.var1 = var1;

        this.var2 = var2;

        this.var3 = var3;

        this.var4 = var4;

    }

}

Is there a way to avoid writing this.varX = varX and save all the variables to the fields if the names are the same?

No, there is no way to do this more easily in the current version of C#. There was a new feature in the C# 6.0 prereleases called Primary Constructors to solve this, but it was removed before the final release. https://www.c-sharpcorner.com/UploadFile/7ca517/primary-constructor-is-removed-from-C-Sharp-6-0/

Currently, I believe the C# team are working on adding records to the language: https://github.com/dotnet/roslyn/blob/features/records/docs/features/records.md - this should make working with simple data classes much simpler, as in F#

If you define your variables first, you can use visual studios' "Quick actions" tool to generate a constructor for you; this gives you a choice of the currently-defined class fields to include.

using this will insert a constructor class with all your selected fields as parameters, and it will assign the values to the fields.

This will not reduce the amount of code, but it will cut back on the amount of typing you need

The answer to your question is no, but you could use properties to get a similar fix:

class MyClass

{

    public int Var1 {get;set;}

    public int Var2 {get;set;}

    public int Var3 {get;set;}

    public int Var4 {get;set;}

    public MyClass(){



    }

}



void Main()

{

   var myClass = new MyClass

   {

     Var1 = 1,

     Var2 = 2,

     Var3 = 3,

   };

}

Short: No, Long: Yes, there is a hack.

You can use a mix of reflection and storing the parameter in a temporary array to achieve that.

class TestClass

{

    public string var1 { get; set; }

    public string var2 { get; set; }

    public string var3 { get; set; }



    public TestClass(string var1, string var2, string var3) : base()

    {

        var param = new { var1, var2, var3 };

        PropertyInfo[] info = this.GetType().GetProperties();



        foreach (PropertyInfo infos in info) {

            foreach (PropertyInfo paramInfo in param.GetType().GetProperties()) {

                if (infos.Name == paramInfo.Name) {

                    infos.SetValue(this, paramInfo.GetValue(param, null));

                }

            }

        }



    }



}

This basically loops through the properties and check's whether the name equals the parameter name, which have been stored in a temporary array (you can't get the parameter value with reflection), and assigns it if they match.

Note: I do not recommend assigning properties like that, but for the sake of proof that it's possible I came up with this.

In simple terms not you cant. The use of this is not necessary, but it is elegant to do and shows intent as to reinforce the fact that a variable is part of the context of a class.

However the problem here arise from the fact that both your parameters and instance variables have the same names.

The compiler is unable to differentiate between same name variables(it night complaints of circular reference).

The use of this keyword allow us we tell the compiler that we are referring to the current instance of that variable.

I think that you can improve the code and coding per se with a better Naming approch for your variables.

Eg var1 var2 var3 they don't really say anything and make the code hard to understand.

Try to be specific and verbose :
Eg firstName, lastName, address and so forth. They are self-explanatory.