string.Compare(string1, string2, CultureInfo.GetCultureInfo("pt-BR"),
               CompareOptions.IgnoreNonSpace | CompareOptions.IgnoreCase) == 0

public class CollationInitializer : CreateDatabaseIfNotExists<MeuContexto>
{
    public override void InitializeDatabase(MeuContextocontext)
    {
        if(!context.Database.Exists())
        {
            using (SqlConnection connection = new SqlConnection("DefaultConnection"))
            {
                connection.Open();
                using(SqlCommand command = new SqlCommand(string.Format("CREATE DATABASE {0} COLLATE Latin1_General_CI_AI", "MinhaBaseDeDados"), connection))
                {
                    command.ExecuteNonQuery();
                }
            }

            SqlConnection.ClearAllPools();
         }

         base.InitializeDatabase(context);
    }
}

public class MeuContexto: DbContext
{
    public MeuContexto() : base("DefaultConnection", throwIfV1Schema: false)
    {
        Database.SetInitializer(new CollationInitializer<MeuContexto>());
        if(!Database.Exists())
        {
            Database.Initialize(true);
         }
     }
}

public class CreateDatabaseCollationInterceptor : IDbCommandInterceptor
{
    private readonly string _collation;

    public CreateDatabaseCollationInterceptor(string collation)
    {
        _collation = collation;
    }

    public void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int> interceptionContext) { }
    public void NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        // Apenas para SQL Server
        if (Regex.IsMatch(command.CommandText, @"^create database [.*]$"))
        {
            command.CommandText += " COLLATE " + _collation;
        }
    }

    public void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext) { }
    public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext) { }
    public void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<object> interceptionContext) { }
    public void ScalarExecuting(DbCommand command, DbCommandInterceptionContext<object> interceptionContext) { }
}

using (controle_estoqueEntities entity = new controle_estoqueEntities())
        {
            return (from a in entity.clientes
                    where ( (a.nome_cliente == nome || a.nome_cliente.Contains(nome)))
                    orderby a.nome_cliente
                    select new ClienteDTO
                    {IdCliente = a.idcliente,
                        NomeCliente = a.nome_cliente}).toList();