Question

我想将集合中的所有文档作为IEnumerable返回。请帮忙！我收到一个错误：

传递到字典中的模型项的类型为'System.Threading.Tasks.Task 1[System.Collections.Generic.IEnumerable 1 [Products.DataLayer.ProductCategory]]'，但是这个字典需要一个类型的模型项 'System.Collections.Generic.IEnumerable`1 [Products.DataLayer.ProductCategory]'。

 public async Task<IEnumerable<ProductCategory>> getAllCategories()
    {
        var client = new MongoClient("mongodb://localhost");
        var database = client.GetDatabase("test");
        var collection = database.GetCollection<BsonDocument>("productcategory");

        var documents = collection.Find(_ => true).ToListAsync();//.ContinueWith(e=>e.Result.AsEnumerable());
        documents.Wait();
        var b = documents.Result.AsEnumerable();
        IEnumerable<ProductCategory> ie = (IEnumerable<ProductCategory>)b;
        return ie;
    }

Answer 1

有两点：

在方法GetCollection<ProductCategory>

使用await代替.Wait() - 这与mongodb无关

public async Task<IEnumerable<ProductCategory>> getAllCategories()
{
    var client = new MongoClient("mongodb://localhost");
    var database = client.GetDatabase("test");
    var collection = database.GetCollection<ProductCategory>("productcategory");

    var documents = await collection.Find(_ => true).ToListAsync();
    return documents;
}

Answer 2

public async Task<IEnumerable<ProductCategory>> getAllCategories()
    {
        var client = new MongoClient("mongodb://localhost");
        var database = client.GetDatabase("test");
        var collection = database.GetCollection<ProductCategory>("productcategory");

        var documents = collection.Find(_ => true).ToListAsync();//.ContinueWith(e=>e.Result.AsEnumerable());
        documents.Wait();
        var b = documents.Result.AsEnumerable();
        IEnumerable<ProductCategory> ie = (IEnumerable<ProductCategory>)b;
        return ie;
    }




    public ActionResult Index()
    {
        var categoryService = new ProductCategoryService();
        var categoryDetails = categoryService.getAllCategories().Result;

        return View(categoryDetails);
    }

MongoDB.Driver C＃2.0查找（缺少FindAll）

2 个答案: