Filtering list based on child element of another list C#

Question

1.00/5 (2 votes)

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i have structure like

C#

public class Categories {
  Public List<categorydescription> LisstOfcategories {get ; set;} 
} 

public class categoryDescription { 
  public string CategoryCode {get ;set;} 
}

And i have List of string which contains some categories like

C#

List<string> lst = new List<string>();

lst.Add("CategoryCode1"); 
lst.Add("CategoryCode2");

and List of Categories as

List<Categories > lstCategories Now how do i filter lstCategoriessuch that CategoryCode having same value defined in lst collection should not be selected in Linq C# ? How can i filter this ?

What I have tried:

i want to query through LINQ, i have tried following which does not compile lstCategories= lstCategories.Where(x => lst.Any(y => y != x.categoryDescription.ForEach(z => z.CategoryCode)));

Posted 10-May-17 0:50am

Member 10004269

Updated 10-May-17 21:34pm

Kornfeld Eliyahu Peter

v4

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[no name] 10-May-17 8:02am

so basically you are trying to populate only "Distint" codes here in you target object?

Member 10004269 10-May-17 8:50am

No i just want to remove CategoryCode from lstCategories which are mentioned in lst

Member 10004269 10-May-17 8:52am

No i just want to remove Categorycode from lstCategories which are mentioned in lst

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Maciej Los · Answer 1 · 2017-05-10T07:21:00

First of all, your model (structure) is wrong!

I'd suggest to create Category object this way:

C#

public class Category
{
	private string sdescription = string.Empty;
	private string scode = string.Empty;

	public Category(string _description)
	{
		sdescription = _description;
	}
	
	public Category(string _description, string _code)
	{
		sdescription = _description;
		scode = _code;
	}
	
	public string Description
	{
		get { return sdescription; }
		set { sdescription = value; }
	}
	
	public string Code
	{
		get { return scode; }
		set { scode = value; }
	}
}

Now, your list could look like:

C#

List<Category> Categories = new List<Category>()
    {
        new Category("Books", "001"),
        new Category("Cars", "002"),
        new Category("Tools", "003")
    };

And another list of categories (CategoryCode):

C#

List<string> lst = new List<string>()
    {
        "Cars",
        "Dogs"
    };

Finall query:

C#

var CategoriesNotOnLst = Categories
    .Where(x => !lst.Any(z => x.Description==z))
    .ToList();

Result:

Description Code
Books       001 
Tools       003

Ehsan Sajjad · Answer 2 · 2017-05-10T07:19:00

Solution 1

You can achieve it by following way:

C#

lstCategories.Where(x => lst.Contains(x.CategoryCode));

Posted 10-May-17 7:19am

Ehsan Sajjad

Comments

Richard Deeming 10-May-17 14:19pm

The question is confusing, but I think the OP wants it the other way round - return the categories that don't exist in lst.

You're also one level too high in the hierarchy: lstCategories is a List<Categories>, but your code expects it to be a List<categoryDescription>.

Maciej Los 10-May-17 14:20pm

Seems, OP wants to get list of categories which not exists on string list...
So, your query should be: lstCategories.Where(x => !lst.Contains(x.CategoryCode));
+4!

Member 10004269 11-May-17 3:34am

No I cant Change Existing Code structure

So i can give you another Explanation as follows

public class Zoo
{
public string zooName {get ; set;}

public List<animaldescriptions> animalDescriptions {get ; set;}
}

public class animalDescriptions

{
public string AnimalName {get ; set;}

}

Now we have List of Zoo as

List<zoo> ZooList = new List<zoo>();

var animaldescriptionsObj = new animalDescriptions { AnimalName = "Monkey"};
var animaldescriptionsObj2 = new animalDescriptions { AnimalName = "tiger"};

zoolist.add({ zooName = "Zoo1", List<animaldescriptions>{animaldescriptionsObj ,animaldescriptionsObj 2 }})

And we have other List of String as
List<string > lst = new List<string>();
lst.Add("Lion");
lst.Add("tiger");

Now i want linq Query so that AnimalNames defined in lst should not be selected from Zoolist ..so in result tiger animal name should be removed from Zoolist