如果你想要调用一个类的方法进行循环操作：官方的例子：

Disabling automatic detection of changes

If you are tracking a lot of entities in your context and you call one of these methods many times in a loop, then you may get significant performance improvements by turning off detection of changes for the duration of the loop. For example:

using (var context = new UnicornsContext())
{
    try
    {
        context.Configuration.AutoDetectChangesEnabled = false;

        // Make many calls in a loop
        foreach (var unicorn in myUnicorns)
        {
            context.Unicorns.Add(unicorn);
        }
    }
    finally
    {
        context.Configuration.AutoDetectChangesEnabled = true;
    }
}

Don’t forget to re-enable detection of changes after the loop—I used a try/finally to ensure it is always re-enabled even if code in the loop throws an exception.

An alternative to disabling and re-enabling is to leave automatic detection of changes turned off at all times and either call context.ChangeTracker.DetectChanges explicitly or use change tracking proxies diligently. Both of these options are advanced and can easily introduce subtle bugs into your application so use them with care.