问题描述

我正在尝试创建一个 Azure 函数，在该函数中我使用 AutoMapper 的一些代码.我对 C#、Azure 和 AutoMapper 还很陌生，在找到初始化 AutoMapper 配置的正确方法时遇到了一些麻烦.

I am trying to create an Azure function in which I am using some code with AutoMapper. I am quite new to C#, Azure and AutoMapper and I'm having some trouble finding the correct way of initializing my AutoMapper configuration.

MapInitializer.cs:

public static class MapInitializer
    {
        public static void Activate()
        {
            Mapper.Initialize(cfg =>
            {
                // initialize mappings here
            });
        }
    }

然后在我的函数中，我正在尝试执行以下操作:

Then in my function, I am trying to do the following:

Function.cs:

public static class ProcessQueueForIntercom
    {

        [FunctionName("ProcessQueue")]
        public static void Run([QueueTrigger("messages")]string myQueueItem, TraceWriter log)
        {
            MapInitializer.Activate(); 

            // rest of the code
        }
    }

现在的问题是，我第一次用这个函数处理消息时，一切都很顺利，代码也按预期运行.但是，从第二次开始，我收到一条错误消息，说我的配置已经初始化.但我真的不知道如何使用 Azure Function 正确执行此操作，因为通常您会在 App Startup 中对其进行初始化，但我认为 Azure Functions (CMIW) 没有这样的事情，并且我没有找到太多关于如何准确执行此操作的信息.我正在考虑用 try catch 来包围 Activate() 调用，然后只记录一个配置已经加载的警告，但这似乎不是很干净......

Now the problem is, the first time I processed a message with this function, everything went smoothly and the code ran as I expected. However, from the second time on, I get an error saying my configuration is already initialized. But I don't really have an idea on how to do this properly with an Azure Function, since normally you would initialize this in the App Startup, but I don't think there is such a thing for Azure Functions (CMIW), and I'm not finding much information about how to exactly do this. I was thinking about just surrounding the Activate() call with a try catch and just log a warning that the configuration is already loaded, but that doesn't seem very clean...

推荐答案

你只需要调用一次Activate.您可以从静态构造函数中执行此操作:

You only need to call Activate once. You can do it from a static constructor:

public static class ProcessQueueForIntercom
{
    static ProcessQueueForIntercom()
    {
        MapInitializer.Activate();
    }

    [FunctionName("ProcessQueue")]
    public static void Run([QueueTrigger("messages")]string myQueueItem, TraceWriter log)
    {             
        // rest of the code
    }
}

或者只是在 MapInitializer 本身上创建一个静态构造函数.

Or just make a static constructor on MapInitializer itself.

另请参阅此答案.

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