Which string comparer is used with switch statements?

Question

How are strings compared when doing switch statements? Does the current culture of the thread / computer affect switch evaluation? I got in the habit of always specifying a comparer when comparing strings, so it would be great to have this confirmed.

I suspect it's StringComparer.Ordinal, but I cannot find any documentation on this.

Unzip

See source : referencesource.microsoft.com/#System/compmod/system/… – Impearl

Answer 1

Does the current culture of the thread / computer affect switch evaluation?

No, it does not.

switch, uses Equals under the covers. Thus it is ordinal:

This method performs an ordinal (case-sensitive and culture-insensitive) comparison.

How do we know switch uses Equals? Well the docs state:

The constant expression is evaluated as follows:

• If expr and constant are integral types, the C# equality operator determines whether the expression returns true (that is, whether expr == constant).

• Otherwise, the value of the expression is determined by a call to the static Object.Equals(expr, constant) method.

The latter bullet point is what applies here.

Estrus

So, it is not literally using StringComparer.Ordinal but it is doing that same comparison. – Unzip

Effectively yes @DavidS. Although referencesource.microsoft.com/#mscorlib/system/… shows that StringComparer.Ordinal uses String.Equals (rather than the other way around). – Estrus