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POHow to use let to define a new set of data within a LINQ query?
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  1. POHow to use let to define a new set of data within a LINQ query?
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    copied!<p>I have a class that represents all the Ingredients for a Recipe</p> <pre><code>public class ViewRecipe { public string RecipeName { get; set; } public string IngredientName { get; set; } public double UnitWeight { get; set; } public double TotalWeight { get; set; } public ViewRecipe() { } public ViewRecipe(string _RecipeName, string _IngredientName, double _UnitWeight, double _TotalWeight) { RecipeName = _RecipeName; IngredientName = _IngredientName; UnitWeight = _UnitWeight; TotalWeight = _TotalWeight; } }(in reality there are a LOT more data members like quantity, weight, etc....) </code></pre> <p>The actual dataset is a List called ViewRecipeSummary and it looks like this:</p> <pre><code>RecipeName IngredientName 1 A 1 B 1 C 2 D 2 E 3 A 3 Z </code></pre> <p>I have an existing query which finds an INGRIDENT (recipeGroup.Key) and I need to now do the following:</p> <p>1- find all recipes that have that ingredient</p> <p>2- return all rows from my data for those recipes</p> <p>And I need to then use this inside my query (so it needs to be with a LET or something)</p> <p>Lets assume I am looking for all recipes that share ingredient A, I expect the end result of my LET (based on the data I show above) to look exactly like this:</p> <pre><code>RecipeName IngredientName 1 A 1 B 1 C 3 A 3 Z </code></pre> <p>So for any recipe that has ingredient A (1 and 3) return all rows of those recipes so I have all the ingredients I need. And this should be in the same form as my ViewRecipe class (not some new {RecipeName, List}, etc...), it should provide the same rows of data in the same format.</p> <p>Current LINQ Query:</p> <pre><code> ViewFullRecipeGrouping = ( from data in ViewRecipeSummary group data by data.RecipeName into recipeGroup let fullIngredientGroups = recipeGroup.GroupBy(x =&gt; x.IngredientName) select new ViewFullRecipe() { RecipeName = recipeGroup.Key, RecipeIngredients = ( from ingredientGroup in fullIngredientGroups select new GroupIngredient() { IngredientName = ingredientGroup.Key, } ).ToList(), ViewGroupRecipes = ( // THIS IS WHERE I NEED TO ADD MY CODE SO THAT I CAN USE THE RESULT BELOW let a = ..... // BUT I HAVE NO CLUE HOW TO PERFORM SUCH A QUERY HERE select new GroupRecipe() { // USE THE RESULTS FOUND TO GENERATE MY RECIPE GROUP // BASED ON THE RESULTS FOUND ABOVE RecipeName = a.key }).ToList(), }).ToList(); </code></pre> <p>Something like:</p> <pre><code> let a = ViewRecipeSummary.GroupBy(x =&gt; x.RecipeName) .Where(g =&gt; g.Any(x =&gt; x.IngredientName == recipeGroup.Key)) .Select(g =&gt; new ViewRecipe() { RecipeName = g.Key, IngredientName = g.Select(x =&gt; x.IngredientName) }) </code></pre> <p>But this returns a List and I need to return it broken down into the same structure.</p> <p>Here are the classes used:</p> <pre><code> public class GroupRecipe { public string RecipeName { get; set; } public List&lt;GroupIngredient&gt; Ingredients { get; set; } public GroupRecipe() { } public GroupRecipe(string _recipeName, List&lt;GroupIngredient&gt; _ingredients) { RecipeName = _recipeName; Ingredients = _ingredients; } } public class GroupIngredient { public string IngredientName { get; set; } public double UnitWeight { get; set; } public double TotalWeight { get; set; } public GroupIngredient() { } public GroupIngredient(string _IngredientName, double _UnitWeight, double _TotalWeight) { IngredientName = _IngredientName; UnitWeight = _UnitWeight; TotalWeight = _TotalWeight; } } public class ViewFullRecipe { public string RecipeName { get; set; } public List&lt;GroupIngredient&gt; RecipeIngredients { get; set; } public List&lt;GroupRecipe&gt; ViewGroupRecipes { get; set; } public ViewFullRecipe() { } public ViewFullRecipe(string _RecipeName, List&lt;GroupIngredient&gt; _RecipeIngredients, List&lt;GroupRecipe&gt; _ViewGroupRecipes) { RecipeName = _RecipeName; RecipeIngredients = _RecipeIngredients; ViewGroupRecipes = _ViewGroupRecipes; } } </code></pre>
 

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