传递给WCF服务的可选查询字符串参数 [英] Optional query string parameter passing to WCF service

问题描述

我想知道如何使用:

string limit = WebOperationContext.Current.IncomingRequest.UriTemplateMatch.QueryParameters["Limit"];

在我的wcf中采用这种方法:

in my wcf in this method:

CityNewsList GetNewsByCity(string DeviceType,string id,string limit);

此处"devicetype"和"id"是默认参数，而我想要的是"limit"，因为这是可选参数，表示用户可以选择传递此参数，他可以通过也可以不通过.

here 'devicetype' and 'id' are default parameter and what i want is 'limit' as optional parameter means user have a choice to pass this parameter he can pass or can not pass this.

想要将限制用作:

if (limit == some value)
{
    //do this.
}
if (limit == null)
{
    // do this.
}

我浏览了很多链接，但是我没有在wcf中使用该链接.

i go through many links but i didn't get that how to use this in my wcf.

或者是否有人可以告诉我如何在WCF服务中使参数成为可选参数.

or if someone can tell me how to make a parameter optional in the WCF Service.

推荐答案

实际上，您是在使用WCF创建REST服务.我已经读过您要创建的可能重复项的问题的答案中的含义:

So actually you're using WCF to create a REST service. I've read what you mean in the answer to the question you're creating a possible duplicate of: How to have optional parameters in WCF REST service?

您可以通过从WebGet或WebInvoke属性上的UriTemplate中省略查询字符串，并使用WebOperationContext.Current.IncomingRequest.UriTemplateMatch.QueryParameters 来获得所需的效果.

You can get the desired effect by omitting the Query string from the UriTemplate on your WebGet or WebInvoke attribute, and using WebOperationContext.Current.IncomingRequest.UriTemplateMatch.QueryParameters.

所以，归结为:

更改方法的签名以省略参数:

Change your method's signature to omit the parameter:

CityNewsList GetNewsByCity(string DeviceType,string id /*,string limit*/);

更改属性，以使查询字符串上不需要该参数:

Change the attributes so that the parameter is not expected on the query string:

[OperationContract]
[WebGet(UriTemplate = "/whatever/{DeviceType}/{id}", RequestFormat = WebMessageFormat.Xml)]

代替

[OperationContract]
[WebGet(UriTemplate = "/whatever/{DeviceType}/{id}/{limit}", RequestFormat = WebMessageFormat.Xml)]

最后，您会得到类似的东西:

In the end you'd have something like:

[OperationContract]
[WebGet(UriTemplate = "/whatever/{DeviceType}/{id}", RequestFormat = WebMessageFormat.Xml)]
CityNewsList GetNewsByCity(string DeviceType,string id);

实现的第一件事是:

string limit = WebOperationContext.Current.IncomingRequest.UriTemplateMatch.QueryParameters["Limit"];

但是:我还没有尝试过，但这是我从您对问题的评论中引用的内容所得到的理解.

However: I have not tried that, but that's what I understand from what you've quoted in the comments to your question.

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