C# Linq、OData和WCF:&x201C；不支持方法join”；

我正在尝试从多个表恢复和显示数据。o我做过这样的多次连接：

var prod = from product in context.PRODUCT
    join islocated in context.ISAUDITEDIN on product.PRODUCT_ID equals islocated.PRODUCT_ID
    join location in context.LOCATION on islocated.LOCATION_ID equals location.LOCATION_ID
    orderby location.LOCATION_ID
    group new
    {
       Location_ID = location.LOCATION_ID,
       Product_ID = product.PRODUCT_ID
    } by location.LOCATION_ID into locat
    select new {
       Location_ID = locat.Key,
       Product = locat
    };

其中，context是导致web服务调用的OData。这个链接起作用了：当我做一个简单的选择时，我能够恢复数据。 然后，我想显示结果中的数据。所以我创造了一个词汇：

Dictionary<string,List<ProductModel>> dict = new Dictionary<string,List<ProductModel>>();
foreach (var locat in prod) {
    List<ProdctModel> products = new List<ProductModel>();
    foreach (var p in locat.Product)
    {
        products.Add(new ProductModel(p.Location_ID, p.Product_ID));
    }
    dict.Add(locat.Location_ID.ToString(), products);
}

但当我运行时，我有以下几点：

“the method join is not supported”
Ligne 131 :            Dictionary<string,List<ProdctModel>> dict = new Dictionary<string,List<ProdctModel>>();
Ligne 132 :            foreach (var locat in prod) {

“不支持方法联接”
Ligne 131:Dictionary dict=new Dictionary（）；
Ligne 132:foreach（产品中的var locat）{

如何解决这个问题？我已经看到了一些使用method.Expand（）代替join的方法，但我不知道如何使用它：你能帮我吗

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谢谢！

我从未将odata与linq一起使用过，但我假设您无法加入不同的远程资源。请尝试先将对象放入内存，然后进行加入：

var products = context.PRODUCT.ToList();
var islocateds = context.ISAUDITEDIN.ToList();
var locations = context.LOCATION.ToList();


var prod = from product in products
                       join islocated in islocateds on product.PRODUCT_ID equals islocated.PRODUCT_ID
                       join location in locations on islocated.LOCATION_ID equals location.LOCATION_ID
                       orderby location.LOCATION_ID
                       group new
                       {
                           Location_ID = location.LOCATION_ID,
                           Product_ID = product.PRODUCT_ID
                       } by location.LOCATION_ID into locat
                       select new {
                           Location_ID = locat.Key,
                           Product = locat
                       };

请记住，这将下载所有3个表

编辑

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另外，创建字典时出现异常的原因是“prod”变量是IEnumerable，它仅在执行“foreach”时执行请求或者类似的东西。

我认为是相同的@Dawoodabasi，但好的答案是什么？@Leandro根据连接方法仍然不受支持。Derbie，作为web服务的消费者，对此无能为力。要使其工作，必须为服务使用不同的框架。假设存在这样的框架。

var products = context.PRODUCT.ToList();
var islocateds = context.ISAUDITEDIN.ToList();
var locations = context.LOCATION.ToList();


var prod = from product in products
                       join islocated in islocateds on product.PRODUCT_ID equals islocated.PRODUCT_ID
                       join location in locations on islocated.LOCATION_ID equals location.LOCATION_ID
                       orderby location.LOCATION_ID
                       group new
                       {
                           Location_ID = location.LOCATION_ID,
                           Product_ID = product.PRODUCT_ID
                       } by location.LOCATION_ID into locat
                       select new {
                           Location_ID = locat.Key,
                           Product = locat
                       };