F#入门-第五章 F#开发实例-第三节 最好知道的注意事项

//OR运算

button.Anchor <- AnchorStyles.Left ||| AnchorStyles.Right;;

//运算参考:比较老式的处理方法

button.Anchor <- Enum.combine[AnchorStyles.Left;AnchorStyles.Right];;

//指定空的时候

let settextattr (t:RichTextBox) =

        t.LanguageOption <- Enum.of_int(0);;

//      t.LanguageOption <- Enum.combine[];;

match object_value with

        | :? string -> print_endline "string value"

        | :? int -> print_endline "int value"

try

        File.Copy(src,dst);

with

        | :? PathTooLongException -> msg "路径太长"

        | :? NotSupportedException -> msg "路径中含有冒号"

        | :? DirectoryNotFoundException -> msg "拷贝路径为Nothing或空文字列"

        | :? UnauthorizedAccessException -> msg "不能访问文件"

        | :? System.Security.SecurityException -> msg "没有必须的访问权限"

let settext (c : #Control) = c.Text <- "text";;

//这样写意思相同

let settext (c : 'a when 'a :> Control) = c.Text <- "text";;

//转换为obj类型

box 1;;

box "abc";;

//从obj类型返回到原来的类型

unbox<string> (box "abc");;

(unbox (box "abc") : string);;

[<System.Obsolete("旧版本的函数")>]

let old () = print_endline "old function";;

use fs = new FileStream(fullpath,FileMode.Open,FileAccess.Read) in

fs.Read(bytes,0,Int32.of_int64 fs.Length) |> ignore;

...