C＃ - LINQ查询 - 保持击球抓 [英] c# - Linq Query - Keeps hitting catch

问题描述

我是新的C＃，所以希望我可以给你在这里的足够信息。

我试图返回的产品，在产品的状态列中值为1的列表。

不过，我一直在打我一抓，并返回null。

我想为每一个产品的清单，但我还没有得到那么远，目前刚刚倾倒的结果变成可视数据。

我在catach获得唯一的例外是：
的无效操作...：不能按类型'Davey.Models.GetAllProducts订单的

下面是我的code：

我的模型：（产品型号）

 命名空间Davey.Models
{
    [DataContract]
    公共类GetAllProducts
    {
        [数据成员]
        公共字符串ID {搞定;组; }
        [数据成员]
        公共字符串名称{;组; }
        [数据成员]
        公共字符串说明{搞定;组; }
        [数据成员]
        公共字符串价格{搞定;组; }
        [数据成员]
        公共字符串点{搞定;组; }
        [数据成员]
        公共字符串猫{搞定;组; }
        [数据成员]
        公共字符串大小{搞定;组; }
        [数据成员]
        公共字符串SizeM {搞定;组; }
        [数据成员]
        公共字符串{SIZEL获得;组; }
        [数据成员]
        公共字符串SizeXL {搞定;组; }
        [数据成员]
        公众诠释状态{搞定;组; }
    }
}
 

我的服务（DaveyService.scs）：//这是我不停的按catch块

 公共GetAllProducts [] AllProducts（INT状态）
{
    尝试
    {
        使用（UserDataDataContext DB =新UserDataDataContext（））
        {
            返回db.mrobProducts.Where（X =＆GT; x.Status ==状态）。选择（X =＆gt;新建GetAllProducts {名称= x.Name，说明= x.Description，价格= x.Price}）排序依据（ X =＆X的催化剂）.ToArray（）;
        }
    }
    抓住
    {
        返回null;
    }
}
 

和我的控制器，它已经被砍倒在相关部分：

  [HttpPost]
[使用AllowAnonymous]
公众的ActionResult用户登陆（LoginModel模型，用户名usernameModel，GetAllProducts allProductsModel）
{
    如果（userExists）
    {
        VAR webService3 =新DaveyServiceClient（）;
        allProductsModel.Status = 1;
        计算机[产品] = webService.AllProducts（allProductsModel.Status）;
        返回视图（../私人/索引）;
    }
    返回查看（「指数」）;
}
 

解决方案

的问题是，你的排序依据方法不知道如何通过 GetAllProducers 。

您有两种选择：

1. 实施 IComparable的＆LT; GetAllProducts＆GT; 在 GetAllProducts



2. 排序东西排序依据将知道如何进行排序，如字符串或 INT ，例如：

    使用（UserDataDataContext DB =新UserDataDataContext（））
   {
        返回db.mrobProducts.Where（X =＆GT; x.Status ==状态）。选择（X =＆gt;新建GetAllProducts
              {
                 名称= x.Name，
                 说明= x.Description，
                 价格= x.Price
              }）的OrderBy（X =＆GT; x.Price）.ToArray（）;
    }
    

作为一个侧面说明

，我通常喜欢指定我抓什么IM捕子句，你应该总是做一些与你捕捉异常，即使它只是日志记录。我建议你​​使用特定类型的如赶上（InvalidOperationException异常E）或者如果你真的需要一个常规catch那么赶上（例外五）

I'm new to c#, so hopefully I can give you enough information here.

I am trying to return a list of products, where the product status column has a value of 1.

But, I keep hitting a my catch, and returning null.

I would like to create a list for each product, but I have not even got that far yet, currently just dumping the results into a viewdata.

The exception I am getting on the catach is: Invalid operation...:Cannot order by type 'Davey.Models.GetAllProducts'.

Here is my code:

My Model: (Product Model)

namespace Davey.Models
{
    [DataContract]
    public class GetAllProducts 
    {
        [DataMember]
        public string ID { get; set; }
        [DataMember]
        public string Name { get; set; }
        [DataMember]
        public string Desc { get; set; }
        [DataMember]
        public string Price { get; set; }
        [DataMember]
        public string Points { get; set; }
        [DataMember]
        public string Cat { get; set; }
        [DataMember]
        public string SizeS { get; set; }
        [DataMember]
        public string SizeM { get; set; }
        [DataMember]
        public string SizeL { get; set; }
        [DataMember]
        public string SizeXL { get; set; }
        [DataMember]
        public int Status { get; set; }
    }
}

My Service (DaveyService.scs): // This is where I keep hitting the catch block

public GetAllProducts[] AllProducts(int status)
{
    try
    {
        using (UserDataDataContext db = new UserDataDataContext())
        {
            return db.mrobProducts.Where(x => x.Status == status).Select(x => new               GetAllProducts { Name = x.Name, Desc = x.Description, Price = x.Price }).OrderBy(x => x).ToArray();
        }
    }
    catch
    {
        return null;
    }
}

And my controller, which has been cut down to the relevant part:

[HttpPost]
[AllowAnonymous]
public ActionResult UserLogin(LoginModel model, UserName usernameModel, GetAllProducts allProductsModel)
{
    if (userExists)
    {                   
        var webService3 = new DaveyServiceClient();
        allProductsModel.Status = 1;
        ViewData["products"] = webService.AllProducts(allProductsModel.Status);
        return View("../Private/Index");
    }       
    return View("Index");
}

解决方案

The problem is that your OrderBy method doesn't know how to sort by GetAllProducers.

You have two choices:

1. Implement IComparable<GetAllProducts> in GetAllProducts

2. Sort by something OrderBy will know how to sort by, like a string or an int, for example:

   using (UserDataDataContext db = new UserDataDataContext())
   {
        return db.mrobProducts.Where(x => x.Status == status).Select(x => new GetAllProducts 
              { 
                 Name = x.Name, 
                 Desc = x.Description, 
                 Price = x.Price 
              }).OrderBy(x => x.Price).ToArray();
    }
   

As a side note, i usually like to specify what im catching in my catch clause, as you should always do something with the exception you catch, even if its just logging. I suggest you use a specific type like catch (InvalidOperationException e) or if you really need a general catch then catch (Exception e)

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