CODEWITHSUNDEEP
c#
wcard
wcard

Reputation: 37

How do I access a constructor with user input in C#

In my program I have multiple instances of a specific class Tracer (A1,B2,C3 etc). Using a listbox called tracerListBox, the user will determine which tracer they want to use.

Lets say each tracer has a constructor named family.

I know that if I wanted to access the family of, say, A1 I would simply type:

    A1.family

However, I want to write code that accomplishes something like this:

    tracerListBox.Text.family

Is there a way to pass a user-determined value to a constructor? I essentially want the user to determine which instance of Class Tracer to use and then use that information to pull all of the information about that specific tracer.

Thanks in advance for any assistance you can provide.

Upvotes: 1

Views: 1132

Answers (3)

Matt Grande
Matt Grande

Reputation: 12157

Are you looking for something like this:

string myType = "MyNamespace." + tracerListBox.Text + ", MyAssembly";
var = Type.GetType( myType );
var property = t.GetProperty("family", BindingFlags.Static);

Upvotes: 1

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726839

What you are looking for is a factory method, sometimes also called a virtual constructor (which is not technically correct, because it's neither a constructor nor a virtual method).

Instead of calling a constructor, you call a static method that calls a constructor of the class determined by the arguments passed in.

interface ITracer {
    void Trace(string s);
}
class TracerA : ITracer {
    public void Trace(string s) {
        // ...
    }
}
class TracerB : ITracer {
    public void Trace(string s) {
        // ...
    }
}
class TracerFactory {
    public static ITracer Make(string name) {
        if (name.Equals("A")) return new TracerA();
        if (name.Equals("B")) return new TracerB();
        throw new ApplicationException("Unknown: "+name);
    }
}

Upvotes: 5

John Fisher
John Fisher

Reputation: 22717

Much of the detail to actually make a decision is missing from your question. However, we can point you in the general directions that may answer your question.

  • Reflection would definitely help. Look at object.GetType() to start.
  • Check out different Dependency Injection or Inversion of Control (IOC) libraries. They may be just what you need.

Upvotes: 1

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