在 f# 匹配语句中，如何匹配字节 [] 类型? [英] in f# match statement how do I match to the type byte[]?

问题描述

我正在尝试从 .net 类型中查找 DbType 枚举值.我正在使用匹配语句.但是我不知道如何匹配 byte[] 类型.

I'm trying to lookup DbType enumeration values from .net types. I'm using a match statement. However I cannot figure out how to match on the type byte[].

let dbType x =
  match x with
  | :? Int64 -> DbType.Int64
  | :? Byte[] -> DbType.Binary // this gives an error
  | _ -> DbType.Object

如果有更好的方法来映射这些类型，我愿意接受建议.

If there is a better way to map these types, I would be open to suggestions.

推荐答案

byte[], byte array, and array都是同义词，但在这种情况下，只有最后一个可以不带括号:

byte[], byte array, and array<byte> are all synonymous, but in this context only the last will work without parentheses:

let dbType (x:obj) =
    match x with
    | :? (byte[])     -> DbType.Binary
    | :? (byte array) -> DbType.Binary // equivalent to above
    | :? array<byte>  -> DbType.Binary // equivalent to above
    | :? int64        -> DbType.Int64
    | _               -> DbType.Object

这篇关于在 f# 匹配语句中，如何匹配字节 [] 类型?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！