StringExMiddle 方法

public static string Middle(
	this string s,
	int start,
	int length
)

<ExtensionAttribute>
Public Shared Function Middle ( 
	s As String,
	start As Integer,
	length As Integer
) As String

[<ExtensionAttribute>]
static member Middle : 
        s : string * 
        start : int * 
        length : int -> string