CODEWITHSUNDEEP
c#linq
Abila
Abila

Reputation: 37

How can I solve LINQ to Entities does not recognize the method 'System.String ToString()' method?

I have checked all examples related to this but have not been able to solve my issue.

I have created check box and if I used to unchecked means getting some values

It return

string selectedid = {"2","6","45","34","5"};  
string[] separteid = Regex.Split(selectedid, ",");

List<string>idlist=new List<string>();
foreach(var item in separteid)
{
     idlist.Add(item);
}

I want to check with integer ID of database table

job = (from n in bc.db.xx where idlist.Contains(n.id.ToString()) select n);
ViewBag.Count = job.Count();

How to fix it? Anyone help?

Upvotes: 1

Views: 108

Answers (3)

Nitin Varpe
Nitin Varpe

Reputation: 10694

You can use following if EF version being used is 4 or above. Check this for more.

SqlFunctions.StringConvert((Decimal)n.id).Trim(),

Or else you can convert your list of string into list of int like below and use .Contains over it.

job = (from n in bc.db.xx where idlist.Select(x=>int.Parse(x)).Contains(n.id) select n);

Upvotes: 3

Ronan Thibaudau
Ronan Thibaudau

Reputation: 3603

A very fix in your case since you're comparing against integers on the DB side would be to pass integers on the C# side instead of passing strings and trying to convert on the other side

The issue is that most of your code doesn't make sense, you're creating a string with list syntax (i'm surprised this even compiles). Then make it into an array by spliting it, then generate a list from that array, all of this could be done in a single step, or better yet you could even declare as a list of int to begin with replacing all of this :

string selectedid = {"2","6","45","34","5"};  
string[] separteid = Regex.Split(selectedid, ",");

List<string>idlist=new List<string>();
foreach(var item in separteid)
{
     idlist.Add(item);
}

with this:

List<int> idlist = new List<int>(){2,6,45,34,5};

And then you already have the right type which allows you to simplify this :

job = (from n in bc.db.xx where idlist.Contains(n.id.ToString()) select n);
ViewBag.Count = job.Count();

To this : 

ViewBag.Count = (from n in bc.db.xx where idlist.Contains(n.id) select n)
    .Count();

Or if you don't mind lambda syntax you can directly pass the predicate to count:

ViewBag.Count = bc.db.xx
    .Count(n=>idlist.Countains(n.id));

Upvotes: 2

sara
sara

Reputation: 3589

If typeof (n.id) == System.String, just remove the ToString() invocation. If the type is int, or something implicitly convertible to an int, transform your list instead:

string[] strIds = new[] {"1", "2", "3"}; // I assume you get these values from somewhere else
var idlist = strIds.Select(int.Parse);
var job = (from n in bc.db.xx
           where idlist.Contains(n.id.ToString())
           select n);

Upvotes: 2

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