如何处理从LINQ to SQL中的存储过程返回的NULLable Int列

CREATE PROCEDURE get_data
    @nullable_int_column int OUTPUT
AS
BEGIN
    -- 存储过程的逻辑
    SET @nullable_int_column = NULL
END

[Table(Name="dbo.sample_table")]
public class SampleTable
{
    [Column(Name="id", IsPrimaryKey=true)]
    public int Id { get; set; }

    [Column(Name="nullable_int_column", CanBeNull=true)]
    public int? NullableIntColumn { get; set; }
}

[Function(Name="dbo.get_data")]
public int? GetData([Parameter(Name="nullable_int_column", DbType="Int")] out int? nullableIntColumn)
{
    nullableIntColumn = null;
    var result = this.ExecuteMethodCall(this, (MethodInfo)(MethodInfo.GetCurrentMethod())).ReturnValue;
    nullableIntColumn = (int?)result;
    return (int?)result;
}

int? nullableIntValue = dataContext.GetData();
int intValue = Convert.ToInt32(nullableIntValue);