傳遞列表<model>作為 Asp.Net Core 中 RedirectToAction() 中的 RouteValue</model>

Question

我需要將一個基於 Model 的列表從一個 Controller 方法傳遞給另一個方法。 MailList用於從一個Model（Family）中提取和過濾數據，另一個CreateMailingList將結果保存到另一個Model（Contributie）中。

Model FilterListVM是一個包含List<Familie>的 ViewModel。 當重定向列表為空時，它應該包含三個記錄。

作為替代方案，我嘗試使用TempData發送列表，但我收到了錯誤消息： InvalidOperationException: The 'Microsoft.AspNetCore.Mvc.ViewFeatures.Infrastructure.DefaultTempDataSerializer' cannot serialize an object of type 'System.Collections.Generic.List 1[DrieHamersV4.Models.Familie]'。

-simplified- controllerMethod 如下所示：

public async Task<IActionResult> MailingList(FilterListVM contributieLijst)
    {

        (...) // several variables that filter the data 
        (...)            
        string flexDefault = contributieLijst.FlexDefault;            
        int? contributieJaar = contributieLijst.ContributieJaar;            
        bool save = contributieLijst.Save;
        string message = contributieLijst.Message;
        var fList = contributieLijst.Ffamilie;
        

        //************** Getting the Data and Filters for Standard Lists
        switch (flexDefault)
        {
            case "contributie":
                fList = await _context.Familie
                    .OrderBy(f => f.Roepnaam).ToListAsync();
                break;
            case (...)                 
                break;                
            default:
                fList = contributieLijst.Ffamilie; //previous selection
                break;
        }
     }

        contributieLijst.Ffamilie = fList; //fList contains 3 records

        //******* Redirects to the next Method  
        if (save == true)
        {
            TempData["mailList"] = fList.ToList(); //gives an ErrorMEssage

            return RedirectToAction("CreateMailingList", contributieLijst);
        }
return View(contributieLijst);
    }

        
public async Task<IActionResult> CreateMailingList(FilterListVM contributielijst)
    { 
        var contributieJaar = contributielijst.ContributieJaar; // This works fine
        //var mailingList = (List<Familie>)TempData["mailList"]; 
        var mailingList = contributielijst.Ffamilie; //This is now empty
        (...)
        

ViewModel FilterListVM

public class FilterListVM
{         
    public bool? Fovl { get; set; }
    public string Fstaak { get; set; }
    public string Fgeslacht { get; set; }
    public bool? Fbloedverwant { get; set; }
    public string Fland { get; set; }
    public bool? Femail { get; set; }
    public bool? Ftelefoon { get; set; }
    public int? FleeftijdVan { get; set; }
    public int? FleeftijdTot { get; set; }
    public bool? Fcorrespondentie { get; set; }

    public string SortColumn { get; set; }
    public string SortOrder { get; set; }
    public string FlexDefault { get; set; }
    public bool ExportToggle { get; set; }

    public string SearchString { get; set; }
    public string CurrentFilter { get; set; }
    public bool Reset { get; set; } = false;
    public int? ContributieJaar { get; set; }
    public bool Save { get; set; } = false;
    public string Message { get; set; }

    public List<Familie> Ffamilie { get; set; }

}

}

Answer 1

在添加到 TempData 之前，您可以將列表序列化為 json 字符串：

using System.Text.Json;
...

TempData["mailList"] = JsonSerializer.Serialize(fList);

然后在您的其他操作中：

var mailList = JsonSerializer.Deserialize<List<Familie>>(TempData["mailList"].ToString());

Answer 2

我按照你提到的那樣嘗試過，並在我的案例中重復了你的錯誤，

楷模：

public class FilterListVM
    {
        public FilterListVM() 
        {
            Ffamilie = new List<Familie>();
        }
        
        public string Message { get; set; }

        public List<Familie> Ffamilie { get; set; }

    }

    public class Familie
    {
        public int Id { get; set; }
        public string  Description { get; set; }
    }

在 Controller 中：

public IActionResult SomeAction()
        {
            var familie1 = new Familie() { Id = 1, Description = "D1" };
            var familie2 = new Familie() { Id = 2, Description = "D2" };            
            var familielist = new List<Familie>() { familie1, familie2, familie1 };
            var vm = new FilterListVM() { Message = "hi" };
            vm.Ffamilie = familielist;             
            
            return RedirectToAction("AnotherAction", routedic1);
        }

        public IActionResult AnotherAction(FilterListVM vm)
        {            
            return Ok();
        }

結果：

UrL：

然后我嘗試創建一個新的 RouteValueDictionary 並添加代碼：

var routedic = new RouteValueDictionary();
            Type vmtype = typeof(FilterListVM);
            foreach (var property in vmtype.GetProperties())
            {
                routedic.Add(property.Name, vmtype.GetProperty(property.Name).GetValue(vm));
            }
return RedirectToAction("AnotherAction", vm)

它的表現和以前一樣，所以在我看來，設計者可能不會考慮通過復雜的 model 包含一個列表來路由值，因為 url 的長度是有限的；

然后我嘗試如下硬編碼：

var routedic1 = new RouteValueDictionary(vm);
            routedic1.Remove("Ffamilie");
            for (int i = 0; i < vm.Ffamilie.Count; i++)
            {
                var key1 = string.Format("Ffamilie[{0}].Id", i.ToString());
                routedic1.Add(key1, vm.Ffamilie[i].Id);
                var key2 = string.Format("Ffamilie[{0}].Description", i.ToString());
                routedic1.Add(key2, vm.Ffamilie[i].Description);
            }
            return RedirectToAction("AnotherAction", routedic1);

這次成功綁定了model，