CODEWITHSUNDEEP
linqdynamic-linq
user1219702
user1219702

Reputation: 221

Dynamic LINQ: Use .NET Contains method to generate a dynamic search method

I have a class Item like

public class Item
{
   public int Id {get;set;}
   public string Name {get;set;}
   public string PartialDescription {get;set;}
   public string FullDescription {get;set;} 
   public doulbe Price {get;set;}
}

I would like to have a dynamic custom query method SearchOverAnyFields() that can accept any number of Item object's properties like:

// key is an input string variable

// one query 
var results = myItems.SearchOverAnyFields(x => x.Name.Contains(key) || x.PartialDescription.Contains(key) || x.Price.ToString().Contains(key));

// or another query 
var results2 = myItems.SearchOverAnyFields(x => x.Name.Contains(key) || x.PartialDescription.Contains(key) || x.Price.ToString().Contains(key) 
|| x.FullDescription.Contains(key));

// or another query
var results3 = myItems.SearchOverAnyFields(x => x.PartialDescription.Contains(key) ||  x.FullDescription.Contains(key));

Please help.

Upvotes: 1

Views: 486

Answers (2)

Pete Martin
Pete Martin

Reputation: 856

Something like this would probably do the job for you...

    public static IEnumerable<Item> SearchOverAnyFields(this IEnumerable<Item> items, string key, params Func<Item,string>[] fields)
    {
        return 
            from item in items 
            from field in fields.
            Where(field => field(item) != null && field(item).Contains(key)) 
            select item;
    }


    public static void ExampleUsage(object[] args)
    {
        var items = new List<Item> { new Item { Name = "badger" }, new Item { PartialDescription = "badger" }, new Item { } };

        // searches items for any item that has "badger" in it's name or PartialDescription
        var result = items.SearchOverAnyFields("badger", i => i.Name, i => i.PartialDescription);

        foreach (var res in result)
            Debug.WriteLine(res);
    }

Calling ExampleUsage() would print two statements to the debug console, to verify they're the correct Items you'd have to build a ToString method for them.

Upvotes: 1

Kirk Broadhurst
Kirk Broadhurst

Reputation: 28738

I'm not really sure what you're looking for here - the functionality you want can be easily achieved with the Where operator.

var results = myItems.Where(x => x.Name.Contains(key) || 
    x.PartialDescription.Contains(key) || x.Price.ToString().Contains(key));

// or another query 
var results2 = myItems.Where(x => x.Name.Contains(key) || 
    x.PartialDescription.Contains(key) || x.Price.ToString().Contains(key) 
    || x.FullDescription.Contains(key));

// or another query
var results3 = myItems.Where(x => x.PartialDescription.Contains(key) ||  
    x.FullDescription.Contains(key));

Does this meet your requirement?

Upvotes: 1

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