C# 4.0 重建ODataQueryOptions对象并返回null的GetInlineCount
在返回PageResult的ODataWebAPI调用中,我从方法参数中提取requestUri,操作过滤项,然后使用新uri构造新的ODataQueryOptions对象 (PageResult方法基于以下内容: ) 以下是原始入站uri,其中包括%24inlinecount=allpagesC# 4.0 重建ODataQueryOptions对象并返回null的GetInlineCount,c#-4.0,asp.net-web-api,odata,C# 4.0,Asp.net Web Api,Odata,在返回PageResult的ODataWebAPI调用中,我从方法参数中提取requestUri,操作过滤项,然后使用新uri构造新的ODataQueryOptions对象 (PageResult方法基于以下内容: ) 以下是原始入站uri,其中包括%24inlinecount=allpages http://localhost:59459/api/apiOrders/?%24filter=OrderStatusName+eq+'Started'&filterLogic=AND&
http://localhost:59459/api/apiOrders/?%24filter=OrderStatusName+eq+'Started'&filterLogic=AND&%24skip=0&%24top=10&%24inlinecount=allpages&_=1376341370337
就返回的数据而言,除了Request.GetInLineCount返回null之外,其他一切都正常工作
这将“终止”客户端的分页,因为客户端ui元素不知道记录的总数
我构造新ODataQueryOptions对象的方式一定有问题
请看下面我的代码。任何帮助都将不胜感激
我怀疑这篇文章可能包含一些线索,但我被难住了
public PageResult<OrderVm> Get(ODataQueryOptions<OrderVm> options)
{
var incomingUri = options.Request.RequestUri.AbsoluteUri;
//manipulate the uri here to suit the entity model
//(related to a transformation needed for enumerable type OrderStatusId )
//e.g. the query string may include %24filter=OrderStatusName+eq+'Started'
//I manipulate this to %24filter=OrderStatusId+eq+'Started'
ODataQueryOptions<OrderVm> options2;
var newUri = incomingUri; //pretend it was manipulated as above
//Reconstruct the ODataQueryOptions with the modified Uri
var request = new HttpRequestMessage(HttpMethod.Get, newUri);
//construct a new options object using the new request object
options2 = new ODataQueryOptions<OrderVm>(options.Context, request);
//Extract a queryable from the repository. contents is an IQueryable<Order>
var contents = _unitOfWork.OrderRepository.Get(null, o => o.OrderByDescending(c => c.OrderId), "");
//project it onto the view model to be used in a grid for display purposes
//the following projections etc work fine and do not interfere with GetInlineCount if
//I avoid the step of constructing and using a new options object
var ds = contents.Select(o => new OrderVm
{
OrderId = o.OrderId,
OrderCode = o.OrderCode,
CustomerId = o.CustomerId,
AmountCharged = o.AmountCharged,
CustomerName = o.Customer.FirstName + " " + o.Customer.LastName,
Donation = o.Donation,
OrderDate = o.OrderDate,
OrderStatusId = o.StatusId,
OrderStatusName = ""
});
//note the use of 'options2' here replacing the original 'options'
var settings = new ODataQuerySettings()
{
PageSize = options2.Top != null ? options2.Top.Value : 5
};
//apply the odata transformation
//note the use of 'options2' here replacing the original 'options'
IQueryable results = options2.ApplyTo(ds, settings);
//Update the field containing the string representation of the enum
foreach (OrderVm row in results)
{
row.OrderStatusName = row.OrderStatusId.ToString();
}
//get the total number of records in the result set
//THIS RETURNS NULL WHEN USING the 'options2' object - THIS IS MY PROBLEM
var count = Request.GetInlineCount();
//create the PageResult object
var pr = new PageResult<OrderVm>(
results as IEnumerable<OrderVm>,
Request.GetNextPageLink(),
count
);
return pr;
}
这就消除了foreach循环 只有当客户端通过查询选项请求InlineCount时,InlineCount才会出现 在修改uri逻辑中,添加查询选项
$inlinecount=allpages
,如果该选项尚未出现
此外,代码中还有一个小错误。您正在创建的新ODataQueryOptions使用新的请求
,其中与GetInlineCount调用一样,您使用的是旧的请求
。它们不一样
应该是,
var count = request.GetInlineCount(); // use the new request that your created, as that is what you applied the query to.
$inlinecount=所有页面都存在于原始和修改后的URI中。您正在对
请求
应用查询,并尝试从请求
读取inlinecount。局部变量vs类属性。我已经更新了答案,也包括了这一点。谢谢@RaghuRamNadiminti。使用局部变量request
而不是类request
解决了问题。同样的解决方案适用于GetNextPageLink()
它应该是request.GetNextPageLink()
,而不是request.GetNextPageLink()
除了查询\分页之外,您是否使用OData支持?如果不是,那么考虑使用LINQ查询字符串作为Web API提供的替代方案,正如在这个问题的答案中一样:在Web API API数据的支持下,不支持对DTOS的投影,这样您可能会看到一些不可预测的行为,并且粘贴的代码具有许多不必要的复杂性。谢谢@roysvork我会查一查的。我在客户端使用infragistics igniteui网格和数据源。看起来Linq to Querystring可以正常工作。我会回来报告的。我发现Infragistics igniteui网格使用LinqToQueryable属性使用web api方法中的数据。但是,我希望能够操纵查询服务器端来处理枚举上的过滤和排序,其中客户端显示枚举的字符串表示形式。或者,我相信有更好的方法来处理枚举。
[JsonConverter(typeof(StringEnumConverter))]
public OrderStatus OrderStatusId { get; set; }
var count = request.GetInlineCount(); // use the new request that your created, as that is what you applied the query to.