可能使用反射创建命名元组类型？

Question

I can create a normal tuple type with Tuple.Create or typeof(Tuple<,>).MakeGenericType etc, but how can I make a named tuple? With other property names than Item1 , Item2 etc, using reflection in runtime.

Answer 1

No, you can't, because named tuples are largely just syntatic sugar.

If you consider this code:

private void button1_Click(object sender, EventArgs e)
{
    var abc = Get();
    MessageBox.Show(string.Format("{0}: {1}", abc.name, abc.age));  
}

private (string name, int age) Get()
{
    return ("John", 30);
}

and then look at the decompiled code (I used JetBrains' dotPeek):

private void button1_Click(object sender, EventArgs e)
{
  ValueTuple<string, int> valueTuple = this.Get();
  int num = (int) MessageBox.Show(string.Format("{0}: {1}", (object) valueTuple.Item1, (object) (int) valueTuple.Item2));
}

[return: TupleElementNames(new string[] {"name", "age"})]
private ValueTuple<string, int> Get()
{
  return new ValueTuple<string, int>("John", 30);
}

You can see that, even though the MessageBox code uses the names, it's actually converted to .Item1 and .Item2 when it's compiled. Therefore, you should just use the ValueType constructor.