c# - 如何在 Action 过滤器中获取当前模型

Question

我有一个通用 Action 过滤器，我想在 OnActionExecuting 方法中获取当前模型。我当前的实现如下所示:

public class CommandFilter<T> : IActionFilter where T : class, new()
{
    public void OnActionExecuting(ActionExecutingContext actionContext)
    {
        var model= (T)actionContext.ActionArguments["model"];
    }
}

如果我的所有型号名称都相同，效果会很好。但我想使用不同的型号名称。

如何解决这个问题？

编辑

public class HomeController : Controller
{
    [ServiceFilter(typeof(CommandActionFilter<CreateInput>))]
    public IActionResult Create([FromBody]CreateInput model)
    {
        return new OkResult();
    }
}

Answer 1

ActionExecutingContext.ActionArguments 只是一个字典，

    /// <summary>
    /// Gets the arguments to pass when invoking the action. Keys are parameter names.
    /// </summary>
    public virtual IDictionary<string, object> ActionArguments { get; }

如果您需要避免硬编码参数名称(“模型”)，则需要遍历它。来自 the same SO answer对于 asp.net:

When we create a generic action filter that needs to work on a class of similar objects for some specific requirements, we could have our models implement an interface => know which argument is the model we need to work on and we can call the methods though the interface.

在你的情况下你可以这样写:

public void OnActionExecuting(ActionExecutingContext actionContext)
{
    foreach(var argument in actionContext.ActionArguments.Values.Where(v => v is T))
    {
         T model = argument as T;
         // your logic
    }
}