contains in linq query

Question

Hi i am using entity framework and LinQ. I have a table objects called users . i have a list called userids. i have to find all users where ids contains in the string. I hav

Answer 1

Try to use this :

protected Expression> BuildContainsExpression(Expression> valueSelector, IEnumerable values)
{
            if (null == valueSelector) { throw new ArgumentNullException("valueSelector"); }

            if (null == values) { throw new ArgumentNullException("values"); }

            ParameterExpression p = valueSelector.Parameters.Single();

            if (!values.Any())
            {
                return e => false;
            }

            var equals = values.Select(value => (Expression)Expression.Equal(valueSelector.Body, Expression.Constant(value, typeof(TValue))));

            var body = equals.Aggregate((accumulate, equal) => Expression.Or(accumulate, equal));

            return Expression.Lambda>(body, p);
}

call the method like this :

var u = context.users.Where(BuildContainsExpression(e => e.Userid, userids)).ToList();

This will solve your problem.