CODEWITHSUNDEEP
.netreflection
rpf
rpf

Reputation: 3712

Reflection: get property value without instantiate

I have a superclass called Transaction that has a property named TransactionId. This property must be set to some value at the constructor of all subclasses. 

public class SubTransaction : Transaction
{
    public SubTransaction() : base()
    {
        this.TransactionId = "IdTransaction";
    }
}

I have lots of this kind of subclasses.

What I want to do: using reflection load the assembly of these SubTransactions and get the Id set by each one. Is that possible?

By the way, I can't instantiate the objects because I don't have all information that I need. It is completely impossible for me to do that.

Upvotes: 1

Views: 247

Answers (2)

Jon Skeet
Jon Skeet

Reputation: 1502756

Well you could try reading the IL of the body of the constructor, but I really wouldn't suggest it.

I wonder whether it might not be better to decorate each class with an attribute, and read that instead...

[TransactionId("IdTransaction")]
public class SubTransaction : Transaction
{
}

The base class could load the transaction ID in the same way, if it still needed to.

Alternatively, each class could declare a constant field, always with the same name:

public class SubTransaction : Transaction
{
    public const string ConstTransactionId = "IdTransaction";

    public SubTransaction() : base()
    {
        this.TransactionId = ConstTransactionId;
    }
}

That should be easy to read with reflection. It's ugly, but you're basically in an ugly situation...

Upvotes: 3

SLaks
SLaks

Reputation: 887867

This is not possible.

Instead, you can create a custom attribute that takes an ID and apply it to each subclass.

Upvotes: 0

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