C#•7mo ago

Dynamically assign values to class instance properties / Indexing class instance properties

I have a class like:

c#
public class MyClass {
  public string StringProperty { get; set; }
  public int IntProperty { get; set; }
  public bool BoolProperty { get; set; }

  private MyClass() {}

  public static MyClass FromData(Dictionary<string, object?> data) {
    MyClass newInstance = new MyClass();
    foreach (var (key, val) in data) {

      // Do some type checking, and then
      // something like: newInstance[key] = (cast)val;

    }
    return newInstance;
  }
}

c#
public class MyClass {
  public string StringProperty { get; set; }
  public int IntProperty { get; set; }
  public bool BoolProperty { get; set; }

  private MyClass() {}

  public static MyClass FromData(Dictionary<string, object?> data) {
    MyClass newInstance = new MyClass();
    foreach (var (key, val) in data) {

      // Do some type checking, and then
      // something like: newInstance[key] = (cast)val;

    }
    return newInstance;
  }
}

Assuming I have a dictionary like:

c#
Dictionary<string, object> data = new Dictionary<string, object>(){
  {"StringProperty", "My string"},
  {"IntProperty", 21},
  {"BoolProperty", true}
};

c#
Dictionary<string, object> data = new Dictionary<string, object>(){
  {"StringProperty", "My string"},
  {"IntProperty", 21},
  {"BoolProperty", true}
};

Is it possible to do something like my method FromData? Where if it exists, each property will be assigned the value from the dictionary?

9 Replies

Angius•7mo ago

With reflections maybe

UnemployedNinja•7mo ago

Could you explain?

Angius•7mo ago

It kinda smells of bad design tho

UnemployedNinja•7mo ago

ehhhh

Angius•7mo ago

As I said, with reflections: https://learn.microsoft.com/en-us/dotnet/csharp/advanced-topics/reflection-and-attributes/ It's fairly slow and inefficient, it discards the safety of the type system, but that's apparently what you want here Alternatively, you could look into source generators Either finding an existing one, or writing one yourself Or, for a fairly hacky way, you could serialize the dictionary to JSON and deserialize it to a class Which would either use reflections or source generation, depending on how you set it up

UnemployedNinja•7mo ago

hmm this seems like a good way tbh 🤔

Angius•7mo ago

In general, though, C# is strictly and statically-typed. Setting properties by string name is far from the norm

DΣX•7mo ago

Which is then just checking the properties in the class and signing them by string name 😁

UnemployedNinja•7mo ago

This is such a hack, but I'm incredibly lazy, and it works so well lol. ty :)

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Dynamically assign values to class instance properties / Indexing class instance properties