我认为这是一个愚蠢(简单)的问题,但我无法找到答案,我可以有效地将 LINQ 用于 XML(这是我的全部 LINQ 体验)但是当我尝试获取实际值时作为来自通用列表或列表(包含在描述中)的字符串,我只得到类似“{System.Linq.Enumerable.WhereSelectListIterator}”的东西,我希望它说“scrambled-eggs.jpg”
private static List<Recipe> currentRecipeList = new List<Recipe>();
public static List<Recipe> CurrentRecipeList { get { return currentRecipeList; } set { currentRecipeList = value; } }//Populated from an XML document
public static string GetSpecificRecipeValue(string recipeName, int index, int ingredientIteration = -1, int ingredientValue = -1)//From CurrentRecipeList get value(Index) where recipeName is equal to CurrentRecipeList.RecipeName.
{
IEnumerable<string> recipeElement = null;
IEnumerable<string> ingredientElement = null;
if (index == 0)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeType); }
else if (index == 1)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeName ); }
else if (index == 2)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeSource); }
else if (index == 3)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeID); }
else if (index == 4)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipePicture); }
else if (index == 5)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeDescription); }
else if (index == 6)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeMethod); }
else if (index == 7)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeCost); }
else if (index == 8)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeDifficulty); }
else if (index == 9)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeServings); }
else if (index == 10)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipePreparationTime); }
else if (index == 11)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeCookingTime); }
else if (index == 12)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeGlobalRating); }
else if (index == 13)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeUserRating); }
else if (index == 14)
{ recipeElement = (from el in currentRecipeList where el.RecipeName == recipeName select el.RecipeTags); }
else if (index == 15 && ingredientValue == 0)
{ ingredientElement = (from el in currentRecipeList where el.RecipeName == recipeName select el.RecipeIngredients[ingredientIteration].Item); }
else if (index == 15 && ingredientValue == 1)
{ ingredientElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeIngredients[ingredientIteration].Quantity); }
else if (index == 15 && ingredientValue == 2)
{ ingredientElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeIngredients[ingredientIteration].Unit.ToString()); }
else if (index == 15 && ingredientValue == 3)
{ ingredientElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeIngredients[ingredientIteration].State); }
else if (index == 15 && ingredientValue == 4)
{ ingredientElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeIngredients[ingredientIteration].Type); }
else
{ recipeElement = null; ingredientElement = null; }
if (recipeElement != null)
{
return recipeElement.ToString();
}
else if (ingredientElement != null)
{
return ingredientElement.ToString();
}
else
{
return null;
}
}
配方类...
public class Recipe
{
public string RecipeType { get; set; }
public string RecipeName { get; set; }
public string RecipeSource { get; set; }
public string RecipeID { get; set; }
public string RecipePicture { get; set; }//File name of Picture to read from pictures folder
public string RecipeDescription { get; set; }//ShortDescription
public string RecipeMethod { get; set; }
public string RecipeCost { get; set; }
public string RecipeDifficulty { get; set; }
public string RecipeServings { get; set; }
public string RecipePreparationTime { get; set; }
public string RecipeCookingTime { get; set; }
public string RecipeGlobalRating { get; set; }
public string RecipeUserRating { get; set; }
public string RecipeTags { get; set; }
public List<Ingredient> RecipeIngredients { get; set; }
}
成分类..
public class Ingredient
{
public string Item { get; set; }
public string Quantity { get; set; }
public string Unit { get; set; }
public string State { get; set; }
public string Type { get; set; }
}
如果您需要任何更多信息,请告诉我,这是我的第一篇文章,尽管我绞尽脑汁、google 和 stackoverflow,但我还是找不到答案。任何其他从 RecipeName 获取特定信息作为参数或我可以自己学习此信息的来源的方法,将不胜感激。
编辑 好的,感谢 BJ Myers,这是作为返回结果的正确解决方案。
private static List<Recipe> currentRecipeList = new List<Recipe>();
public static List<Recipe> CurrentRecipeList { get { return currentRecipeList; } set { currentRecipeList = value; } }//Populated from an XML document.
public static string GetSpecificRecipeValue(string recipeName, int index, int ingredientIteration = -1, int ingredientValue = -1)//From CurrentRecipeList get value(Index) where recipeName is equal to CurrentRecipeList.RecipeName.
{
IEnumerable<string> recipeElement = null;
IEnumerable<string> ingredientElement = null;
if (index == 0)
{ recipeElement = (from el in currentRecipeList where recipeName == el.RecipeName select el.RecipeType); }
else if (index == 1)
...
if (recipeElement != null)
{
string result = recipeElement.FirstOrDefault<string>().ToString();
return result;
}
else if (ingredientElement != null )
{
return ingredientElement.FirstOrDefault<string>().ToString();
}
else
{
return null;
}
最佳答案
答案:.FirstOrDefault
from 返回所需的值而不是实现 IEnumerable 的类。
string result = recipeElement.FirstOrDefault<string>().ToString();
return result;
关于c# - 在 foreach 语句中使用 LINQ 从泛型 List<T> 中检索值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40325945/