Question

我有一个为ASP.NET MVC加载大型选择列表的函数。该函数具有354行的方法。我想重构更多函数或局部字段，以便每个函数少于40行。

以下是代码段：

public static SelectList CreateShutterSpeedList()
        {
            var shutterSpeedList = new List<CameraSettingItem>();

            var secNotationPostfix = "\"";

            shutterSpeedList.Add(new CameraSettingItem
            {
                Id = ShutterSpeedDefaultValue,
                Description = string.Empty
            });

            shutterSpeedList.Add(new CameraSettingItem
            {
                Id = 1,
                Description = "30" + secNotationPostfix
            });

etc

也许私人列表作为变量？或从文件加载？或者......？

Answer 1

如果按顺序分配ShutterSpeedDefaultValue以上的ID，您可以先创建一个描述数组，然后使用LINQ将其转换为CameraSettingItem列表：

var descriptions = new[] {
    string.Empty
,   "30" + secNotationPostfix
,   ...
};
shutterSpeedList = descriptions
    .Select((d,i) => new CameraSettingItem {
        Id = i==0 ? ShutterSpeedDefaultValue : i
    ,   Description = d
    })
    .ToList();

您还可以在方法正文之外创建CameraSettingItem列表，如下所示：

private const string secNotationPostfix = "\"";

private static IList<CameraSettingItem> shutterSpeedList = new List<CameraSettingItem> {
    new CameraSettingItem {
        Id = ShutterSpeedDefaultValue,
        Description = string.Empty
    },
    new CameraSettingItem {
        Id = 1,
        Description = "30" + secNotationPostfix
    },
    ...
};

public static SelectList CreateShutterSpeedList() {
    return new SelectList(shutterSpeedList, "Id", "Description");
}

Answer 2

您可以在JSON或XML文件中存储所需的项目，并在需要使用enrich或JavaScriptSerializer时对其进行反序列化，例如：

public static SelectList CreateShutterSpeedList(
{
    var json = File.ReadAllText(@"\ShutterSpeedList.json");
    var shutterSpeedList = JsonConvert.DeserializeObject<List<CameraSettingItem>>(json);
    // Convert shutterSpeedList to SelectList and return
}

或者，如果您可以访问CameraSettingItem代码，则可以使用集合初始值设定项（如@dasblinkenlight指出）和带有可选参数/对象初始值设定项的构造函数来减少行数：

public static SelectList CreateShutterSpeedList()
{
    var secNotationPostfix = "\"";    
    var shutterSpeedList = new List<CameraSettingItem>
    {
        new CameraSettingItem(id: ShutterSpeedDefaultValue),
        new CameraSettingItem(id: 1, description: "30" + secNotationPostfix),
        ...
    };
    // Convert shutterSpeedList to SelectList and return
}

重构到更小的功能，怎么样？

2 个答案: