Question

我已遵循本教程https://docs.microsoft.com/en-us/aspnet/core/performance/caching/memory?view=aspnetcore-2.2

例如，使用依赖注入使[ProtoInclude(4, Whatever)] [ProtoInclude(7, WhateverElse)] class Foo { [ProtoMember(1, ...)] ... [ProtoMember(2, ...)] ... [ProtoMember(3, ...)] ... [ProtoMember(5, ...)] ... [ProtoMember(6, ...)] ... [ProtoMember(8, ...)] ... }仅在特定控制器中可用

[ProtoInclude(101, Whatever)]
[ProtoInclude(102, WhateverElse)]
class Foo {
   [ProtoMember(1, ...)] ...
   [ProtoMember(2, ...)] ...
   [ProtoMember(3, ...)] ...
   [ProtoMember(4, ...)] ...
   [ProtoMember(5, ...)] ...
   [ProtoMember(6, ...)] ...
}

现在，如果我尝试在相同名称空间或不同控制器中访问IMemoryCache值

public class TController : ControllerBase
{
    public IConfiguration Configuration { get; }

    private IMemoryCache _cache;

    public TController(IConfiguration configuration, IMemoryCache memoryCache)
    {
        Configuration = configuration;
        _cache = memoryCache;
    }

    public IActionResult GetAccessToken()
    {

        string key ="IDGKey";
        string obj;
        if (!cache.TryGetValue<string>(key, out obj))
        {
            obj = DateTime.Now.ToString();
            _cache.Set<string>(key, obj);
        }
        return obj;

    }
}

出现以下错误-

名称'_cache'在当前上下文中不存在（CS0103）

如何使_cache适用于所有控制器？

Answer 1

首先，您需要定义一些使用IMemoryCache

的基本控制器类。

public abstract class MyBaseController : ControllerBase
{
    public IConfiguration Configuration { get; }
    protected IMemoryCache _memoryCache;

    public MyBaseController(IConfiguration configuration, IMemoryCache memoryCache)
    {
        Configuration = configuration;
        _memoryCache = memoryCache;
    }
}

然后从中继承您的控制器，不要忘记调用基类构造函数以实例化IMemoryCache

public class MyController : MyBaseController
{
    public MyController(IConfiguration configuration, IMemoryCache memoryCache): base(configuration, memoryCache)
    {
    }

    public IActionResult Action()
    {
        var value = _memoryCache.Get("some key");
        return Ok();
    }
}

如何使IMemoryCache在所有控制器中可用？

1 个答案: