CODEWITHSUNDEEP
c#dependency-injection
Chris Xue
Chris Xue

Reputation: 2537

In C#, is there a way to force some properties to be initialized in object initializer?

Consider the following code:

public class ClassA
{
    public int PropertyA { get; set; }
    public int PropertyB { get; set; }
}

// Somewhere else
var obj = new ClassA
{
    PropertyA = 1,
    // Question:
    // How do we force PropertyB to be set here without making it a parameter in the constructor?
    // Ideally in compile time so that the code here would cause a compile error.
};

Motivation: This question came to me when I tried to inject dependencies by properties instead of in constructors.

Upvotes: 1

Views: 787

Answers (1)

Matthew Watson
Matthew Watson

Reputation: 109537

Perhaps you don't realise this, but you can combine an object initialiser with a constructor.

So you can force initialisation in the constructor and still allow an object initialiser like so:

public class ClassA
{
    public ClassA(int propertyB)
    {
        PropertyB = propertyB;
    }

    public int PropertyA { get; set; }
    public int PropertyB { get; set; }
}

Hence:

var obj = new ClassA(2 /*Property B*/)
{
    PropertyA = 1
};

However, in answer to your question: No, you can't force a property to be initialised in an object initialiser.

Upvotes: 4

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