c# - 如何在 ActionFilterAttribute 的 OnActionExecuting 中区分 C# 中的两个 rest 调用

Question

我已经编写了自己的自定义属性，派生自 ActionFilterAttribute，比如 [TestAttr]。我正在覆盖方法 OnActionExecuting 和 OnResultExecuted。我还添加了一个检查，确保我的 [TestAttr] 应用于如下所示的 Controller 方法

public override void OnActionExecuting(ActionExecutingContext context)
{
   if (context.ActionDescriptor is ControllerActionDescriptor)
   {
       //Need to store a variable int x = 100 here which I want to use later on OnResultExecuted method.
       //value of x will keep on changing for different requests. 
       //Is there any way to differentiate between two requests when we land here.
   }
}

public override void OnResultExecuted(ResultExecutedContext context)
{
   if (context.ActionDescriptor is ControllerActionDescriptor)
   {
       //Do Desired stuff.
       //Use the value of x
   }
}

基本上，我想做以下事情OnActionExecuting 方法调用实际休息电话OnResultExecuted 方法调用

但我想在 OnActionExecuting 调用中存储一个值，然后在 OnResultExecuted 方法中使用它。这不应覆盖多个请求中的值。

Answer 1

你可以使用 HttpContext.Items存储值以供稍后在请求流中使用。例如:

public class FooAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext context)
    {
        // Store the value...
        context.HttpContext.Items.Add("MyValue", 100);

        base.OnActionExecuting(context);
    }

    public override void OnResultExecuted(ResultExecutedContext context)
    {
        // Retrieve the value...
        if (context.HttpContext.Items.TryGetValue("MyValue", out var value))
        {
            // We know this is an int so cast it
            var intValue = (int)value;
        }

        base.OnResultExecuted(context);
    }
}