How to use parameters in Entity Framework in a “in” clause?

Question

I am using Entity Framework 4.0 and I want to use the following query:

To do that I do the following:

strSQLQuery = \"select * from MyTable where IDD         


        

Answer 1

There are a few problems with your code.

First off, to fix your data type error, you'd have to convert strIDs to integers before doing anything else. This should work

var ids = strIDs.Select(s => long.Parse(s));

Now, since you're using entity framework already, why not use Linq instead of creating a SQL query?

var results =
    from r in myContext.MyTable
    where ids.Contains(r.IDData)
    select r;

Or in fluent syntax

var results = myContext.MyTable.Where(r => strIDs.Contains(r.IDData));

But if you really want to use SQL, the IN operator does not support parameters like that. You'd have to write it like this:

strSQLQuery = "select * from MyTable where IDData IN(@ID1, @ID2, @ID3, ...)";

So to do this without too much effort, you can generate your query from ids like this:

strSQLQuery = "select * from MyTable where IDData IN(" + String.Join(", ", ids.Select((s, i) => "@ID" + i)) + ")";
foreach(var parameter in ids.Select((s, i) => new SqlParameter("@ID" + i, s)))
{
    lstParametros.Add(parameter);
}