如何引用没有类名的全局静态Dictionary？

Question

我有一个名为SQL.cs的文件，看起来像这样（为了简洁起见，编辑了查询）：

using System.Collections.Generic;

public static class SQL
{
    public static readonly Dictionary<string, string> SQL = new Dictionary<string, string>()
    {
        {"Customers",       "SELECT * FROM customers"},
        {"OverdueInvoices", "SELECT * FROM invoices WHERE overdue = true"},
    };
}

从Main.cs，我必须像这样引用它：

new MySqlCommand(SQL.SQL["Customers"]);

如何消除第一个SQL？即我想用：

new MySqlCommand(SQL["Customers"]);

Answer 1

使用const string代替Dictionary可能更好。然后，您可以轻松地引用它们并获得编译时错误。

public static class SQL
{
    public const string Customers = @"SELECT * FROM Customers";
}

//Wherever you're going to use it
new MySqlCommand(SQL.Customers);

Answer 2

目前，你无法做到这一点。你可以使用静态索引器，但它们不是。

在C＃6.0中，这将通过静态using语句提供。

此代码在Visual Studio 2014 CTP 2中编译：

using System.Collections.Generic;
using ConsoleApplication2.SQL;

namespace ConsoleApplication2
{
    class Program
    {
        public static void Main(string[] args)
        {
            string command = Commands["Customers"];
        }
    }

    public static class SQL
    {
        public static readonly Dictionary<string, string> Commands = new Dictionary<string, string>()
        {
            {"Customers",       "SELECT * FROM customers"},
            {"OverdueInvoices", "SELECT * FROM invoices WHERE overdue = true"},
        };
    }
}