c# 7.0: switch on System.Type

Question

No existing question has an answer to this question.

In c# 7, can I switch directly on a System.Type?

When I try:

    switch (Type)
    {
      case typeof(int):
        break;
    }

it tells me that typeof(int) needs to be a constant expression.

Is there some syntatic sugar that allows me to avoid case nameof(int): and directly compare the types for equality? nameof(T) in a case statement is not completely good because namespaces. So although name collision is probably not be applicable for int, it will be applicable for other comparisons.

In other words, I'm trying to be more type-safe than this:

    switch (Type.Name)
    {
      case nameof(Int32):
      case nameof(Decimal):
        this.value = Math.Max(Math.Min(0, Maximum), Minimum); // enforce minimum 
        break;
    }

Answer 1

The (already linked) new pattern matching feature allows this.

Ordinarily, you'd switch on a value:

switch (this.value) {
  case int intValue:
    this.value = Math.Max(Math.Min(intValue, Maximum), Minimum);
    break;
  case decimal decimalValue:
    this.value = Math.Max(Math.Min(decimalValue, Maximum), Minimum);
    break;
}

But you can use it to switch on a type, if all you have is a type:

switch (type) {
  case Type intType when intType == typeof(int):
  case Type decimalType when decimalType == typeof(decimal):
    this.value = Math.Max(Math.Min(this.value, Maximum), Minimum);
    break;
}

Note that this is not what the feature is intended for, it becomes less readable than a traditional if...else if...else if...else chain, and the traditional chain is what it compiles to anyway. I do not recommend using pattern matching like this.