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将多个if语句转换为短语句

if-statement .net c#

Shaiju T · 技术社区 · 6 年前

我想用逗号分隔 string 基于 boolean 中的属性值 model .

代码

        string options = string.Empty;

        if (model.Fruits.Value)
        {
            options += "FR,";
        }
        if (model.Drinks.Value)
        {
            options += "DR,";
        }
        if (model.Lunch.Value)
        {
            options += "LU,";
        }
        if (model.Dinner.Value)
        {
            options += "DI,";
        }

我们能把上面的代码简写下来吗? ternary conditional operator (?:) 或者我应该保留上面的那个,因为它更可读?

任何建议都很好。

2 回复 | 直到 6 年前

Marc Gravell 6 年前

可能有一些这种方法的优点如下:

    string options = 
        (model.Fruits.Value ? "FR," : "")
        + (model.Drinks.Value ? "DR," : "")
        + (model.Lunch.Value ? "LU," : "")
        + (model.Dinner.Value ? "DI," : "");

具体来说,这将是 string.Concat (见 example here -你在找单曲 call string [mscorlib]System.String::Concat(string, string, string, string) ,这样就避免了大量中间字符串( += )在“所有选项”场景中。但是,坦率地说,我建议使用 [Flags] enum 相反,即

[Flags]
enum FoodOptions {
    None = 0,
    Fruits = 1,
    Drinks = 2,
    Lunch = 4,
    Dinner = 8,
}

var options = FoodOptions.None;
if(model.Fruits.Value) options |= FoodOptions.Fruits;
if(model.Drinks.Value) options |= FoodOptions.Drinks;
if(model.Lunch.Value) options |= FoodOptions.Lunch;
if(model.Dinner.Value) options |= FoodOptions.Dinner;

它只是整数。

Md. Tazbir Ur Rahman Bhuiyan 6 年前

稍微升级一下代码。我想这可能对你有帮助。

using System;
using System.Text;

public class Program
{
public static void Main()
{
       StringBuilder options = new StringBuilder();
    Food model= new Food();


    if (model.Fruits.HasValue)
    {
        options.Append("FR,");
    }
    if (model.Drinks.HasValue)
    {
        options.Append("DR,");
    }
    if (model.Lunch.HasValue)
    {

        options.Append("LU,");
    }
    if (model.Dinner.HasValue)
    {
        options.Append("DI,");
    }
    Console.WriteLine(options);
}
}

public class Food{
public int? Fruits{get;set;}
public int? Drinks{get;set;}
public int? Lunch{get;set;}
public int? Dinner{get;set;}

public Food(){
    Fruits=1;
    Drinks=null;
    Lunch=2;
    Dinner=3;
}

}

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