C#中如何按食谱名称查询并展示对应食材信息？

问题根源 #

你当前用多个独立的List（比如ingredientNames、ingredientQuantities）分散存储食谱数据，没有把单个食谱的所有信息（名称、食材、步骤）关联起来，导致新食谱的食材会覆盖旧食谱的索引位置，所以只能获取最后一条食谱的信息。

解决方案：面向对象重构数据结构 #

通过创建封装类，把单个食谱的所有信息打包成对象，再用一个列表存储所有食谱，就能轻松关联和访问任意食谱的信息。

1. 定义实体类

// 封装单份食材的所有属性
public class Ingredient
{
    public string Name { get; set; }
    public double Quantity { get; set; }
    public string Unit { get; set; }
    public int Calories { get; set; }
    public string FoodGroup { get; set; }
}

// 封装单个食谱的所有信息
public class Recipe
{
    public string Name { get; set; }
    public List<Ingredient> Ingredients { get; set; } = new List<Ingredient>();
    public List<string> Steps { get; set; } = new List<string>();
    // 自动计算总卡路里
    public int TotalCalories => Ingredients.Sum(i => i.Calories);
}

2. 重构RecipeDetails方法

修改后该方法负责创建单个食谱对象并添加到全局列表：

// 全局存储所有食谱的列表
private List<Recipe> _allRecipes = new List<Recipe>();

public void RecipeDetails()
{
    var newRecipe = new Recipe();

    Console.WriteLine("Enter Name of recipe : ");
    newRecipe.Name = Console.ReadLine();

    Console.WriteLine("Enter Number of ingredients : ");
    if (!int.TryParse(Console.ReadLine(), out int maxIngredients))
    {
        Console.WriteLine("Invalid number, defaulting to 1 ingredient.");
        maxIngredients = 1;
    }

    // 收集食材
    for (int ingredientCount = 0; ingredientCount < maxIngredients; ingredientCount++)
    {
        var ingredient = new Ingredient();

        Console.WriteLine($"Enter name of ingredient {ingredientCount + 1}:");
        ingredient.Name = Console.ReadLine();

        // 循环直到输入有效数量
        while (true)
        {
            Console.WriteLine($"Enter quantity of {ingredient.Name} : 1, 2, 4, 6, 8, 10 :");
            if (double.TryParse(Console.ReadLine(), out double quantity))
            {
                ingredient.Quantity = quantity;
                break;
            }
            Console.WriteLine("Enter Numeric values only !");
        }

        Console.WriteLine($"Enter unit of measurement for {ingredient.Name}: Single, Bunch, Tsp, Cup ");
        ingredient.Unit = Console.ReadLine();

        Console.ForegroundColor = ConsoleColor.Blue;
        Console.WriteLine("- A calorie is a unit of energy commonly used to measure the amount of energy in food and the energy expended through physical activity -");
        Console.ForegroundColor = ConsoleColor.White;

        // 循环直到输入有效卡路里值
        while (true)
        {
            Console.WriteLine($"Enter amount of calories for {ingredient.Name}: ");
            if (int.TryParse(Console.ReadLine(), out int calories))
            {
                ingredient.Calories = calories;
                break;
            }
            Console.WriteLine("Enter Numeric values only !");
        }

        Console.ForegroundColor = ConsoleColor.Blue;
        Console.WriteLine("- A food group is a category of foods that share similar nutritional properties -");
        Console.ForegroundColor = ConsoleColor.White;
        Console.WriteLine($"Enter the food group {ingredient.Name} belongs to. (Fruit, Vegetables, Grains, Protein or Dairy) : ");
        ingredient.FoodGroup = Console.ReadLine();

        newRecipe.Ingredients.Add(ingredient);
    }

    // 收集步骤
    Console.WriteLine("Enter number of steps : ");
    if (!int.TryParse(Console.ReadLine(), out int steps))
    {
        Console.WriteLine("Invalid number, defaulting to 1 step.");
        steps = 1;
    }

    for (int s = 0; s < steps; s++)
    {
        Console.WriteLine($"Enter description of step {s + 1}");
        string description = Console.ReadLine();
        newRecipe.Steps.Add(description);
    }

    // 将新食谱添加到全局列表
    _allRecipes.Add(newRecipe);
}

1. 如何展示从列表获取的用户输入？ #

编写方法根据食谱名称查找并输出对应信息：

public void DisplayRecipe(string recipeName)
{
    // 忽略大小写查找食谱
    var recipe = _allRecipes.FirstOrDefault(r => string.Equals(r.Name, recipeName, StringComparison.OrdinalIgnoreCase));

    if (recipe == null)
    {
        Console.WriteLine($"Recipe '{recipeName}' not found.");
        return;
    }

    Console.WriteLine($"\n=== {recipe.Name} ===");
    Console.WriteLine($"Total Calories: {recipe.TotalCalories}");
    Console.WriteLine("\nIngredients:");
    foreach (var ingredient in recipe.Ingredients)
    {
        Console.WriteLine($"- {ingredient.Quantity} {ingredient.Unit} of {ingredient.Name} ({ingredient.Calories} calories, {ingredient.FoodGroup})");
    }

    Console.WriteLine("\nSteps:");
    for (int i = 0; i < recipe.Steps.Count; i++)
    {
        Console.WriteLine($"{i + 1}. {recipe.Steps[i]}");
    }
}

// 调用示例：提示用户输入要查看的食谱名称
public void PromptDisplayRecipe()
{
    Console.WriteLine("\nEnter the name of the recipe you want to view:");
    string name = Console.ReadLine();
    DisplayRecipe(name);
}

2. 如何访问循环添加到列表中的项？ #

所有食谱存储在_allRecipes列表中，可通过以下方式访问：

• 通过索引访问（比如获取第一个食谱）：

if (_allRecipes.Count > 0)
{
    Recipe firstRecipe = _allRecipes[0];
    Console.WriteLine($"First recipe: {firstRecipe.Name}");
}

• 遍历所有食谱：

Console.WriteLine("\nAll Recipes:");
foreach (var recipe in _allRecipes)
{
    Console.WriteLine($"- {recipe.Name} ({recipe.Ingredients.Count} ingredients, {recipe.Steps.Count} steps)");
}

• 条件筛选访问（比如找出卡路里超过500的食谱）：

var highCalorieRecipes = _allRecipes.Where(r => r.TotalCalories > 500).ToList();
Console.WriteLine($"\nHigh calorie recipes ({highCalorieRecipes.Count}):");
foreach (var recipe in highCalorieRecipes)
{
    Console.WriteLine($"- {recipe.Name}: {recipe.TotalCalories} calories");
}

内容的提问来源于stack exchange，提问作者Avient_711