Comparing an entity with array using LINQ

Question

I have a string array named batches that contains batchnames. I want to compare it with Batch entity and get all the records that matches with batchName field of entity. I am using Entity Framework 6.

class Batch   
{  
   int batchId { get; set;}  
   string batchname { get; set;}  
   string info { get; set;}  
   DateTime date { get; set;}  
}

Right now I am doing it like this using foreach

foreach(var item in batches)
{
   var res=opt.Batch.Where(i=>i.batchname==item).FirstOrDefault();
   batchlist.Add(res);
}

How can I do it with LINQ without using foreach

Rob Aston · Accepted Answer · 2014-02-17 10:37:30Z

4

You can replace the whole foreach loop and keep the 2 lines of code, replacing i.batchname==item with the following:

batches.Contains(i.batchname)

You can then add all items at once to your list as this will return all batches where the name is in the batches array.

The variable res will return an enumerable which can then either be looped around to add to your list or you can use a list that allows AddRange()

Hope this helps.

edited Feb 17, 2014 at 10:37

answered Feb 17, 2014 at 10:28

Rob Aston

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Comments

ebb · Accepted Answer · 2014-02-17 10:44:14Z

2

What about something like:

var batchlist = opt.Batch.Where(x => batches.Contains(x.batchname)).ToList();

answered Feb 17, 2014 at 10:44

ebb

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Comments

Imran Rizvi · Accepted Answer · 2014-02-17 10:33:37Z

0

Something like below will help.

foreach(var item in batches)
{
  batchlist.AddRange(opt.Batch.Where(i=>i.batchname.Any(item => i.batchname==item)).ToList());
}

answered Feb 17, 2014 at 10:33

Imran Rizvi

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Comments

martijn · Accepted Answer · 2014-02-17 10:41:45Z

0

This will get you a list of Batch objects:

var resultList = opt.Batch.Join(batches, left => left.batchname, right => right, (left, right) => left

changing the last 'left' to 'right', will give you a string list of batch names

var resultList = opt.Batch.Join(batches, left => left.batchname, right => right, (left, right) => right

answered Feb 17, 2014 at 10:41

martijn

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