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Where IN clause in LINQ

Asked 2009-06-06T14:08:05.110
195

How to make a where in clause similar to one in SQL Server?

I made one by myself but can anyone please improve this?

    public List<State> Wherein(string listofcountrycodes)
    {
        string[] countrycode = null;
        countrycode = listofcountrycodes.Split(',');
        List<State> statelist = new List<State>();

        for (int i = 0; i < countrycode.Length; i++)
        {
            _states.AddRange(
                 from states in _objdatasources.StateList()
                 where states.CountryCode == countrycode[i].ToString()
                 select new State
                 {
                    StateName  = states.StateName                    

                 });
        }
        return _states;
    }
c# linq
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2 Answers

50

I like it as an extension method:

public static bool In<T>(this T source, params T[] list)
{
    return list.Contains(source);
}

Now you call:

var states = _objdatasources.StateList().Where(s => s.In(countrycodes));

You can pass individual values too:

var states = tooManyStates.Where(s => s.In("x", "y", "z"));

Feels more natural and closer to sql.

answered 2013-06-17T18:19:40.537
1
public List<State> GetcountryCodeStates(List<string> countryCodes)
{
    List<State> states = new List<State>();
    states = (from a in _objdatasources.StateList.AsEnumerable()
    where countryCodes.Any(c => c.Contains(a.CountryCode))
    select a).ToList();
    return states;
}
answered 2011-08-24T12:23:52.487

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