将复杂对象存储在TempData中 [英] Store complex object in TempData

问题描述

我一直试图通过使用TempData来将数据传递给重定向后的操作，如下所示:

I've been trying to pass data to an action after a redirect by using TempData like so:

if (!ModelState.IsValid)
{
    TempData["ErrorMessages"] = ModelState;
    return RedirectToAction("Product", "ProductDetails", new { code = model.ProductCode });
}

但不幸的是，它失败并显示以下消息:

but unfortunately it's failing with the following message:

'System.InvalidOperationException Microsoft.AspNet.Mvc.SessionStateTempDataProvider'无法序列化 类型为'ModelStateDictionary'的会话状态的对象.'

'System.InvalidOperationException The Microsoft.AspNet.Mvc.SessionStateTempDataProvider' cannot serialize an object of type 'ModelStateDictionary' to session state.'

我在 Github中的MVC项目中发现了一个问题，但是解释了为什么我会收到此错误，但我看不出有什么可行的选择.

I've found an issue in the MVC project in Github, but while it explains why I'm getting this error, I can't see what would be a viable alternative.

一种选择是将对象序列化为json字符串，然后反序列化并重建ModelState.这是最好的方法吗?我是否需要考虑任何潜在的性能问题?

One option would be to serialize the object to a json string and then deserialize it back and reconstruct the ModelState. Is this the best approach? Are there any potential performance issues I need to take into account?

最后，对于序列化复杂对象或使用不涉及使用TempData的其他模式，是否有其他选择?

And finally, are there any alternatives for either serializing complex object or using some other pattern that doesn't involve using TempData?

推荐答案

您可以创建如下扩展方法:

You can create the extension methods like this:

public static class TempDataExtensions
{
    public static void Put<T>(this ITempDataDictionary tempData, string key, T value) where T : class
    {
        tempData[key] = JsonConvert.SerializeObject(value);
    }

    public static T Get<T>(this ITempDataDictionary tempData, string key) where T : class
    {
        object o;
        tempData.TryGetValue(key, out o);
        return o == null ? null : JsonConvert.DeserializeObject<T>((string)o);
    }
}

而且，您可以按以下方式使用它们:

And, you can use them as follows:

说objectA是ClassA类型.您可以使用上述扩展方法将其添加到临时数据字典中，如下所示:

Say objectA is of type ClassA. You can add this to the temp data dictionary using the above mentioned extension method like this:

TempData.Put("key", objectA);

要检索它，您可以执行以下操作:

And to retrieve it you can do this:

var value = TempData.Get<ClassA>("key") 检索到的value的类型将为ClassA

var value = TempData.Get<ClassA>("key") where value retrieved will be of type ClassA

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