c# - 无法从Asp MVC 6 Web Api使用HttpClient

我尝试编写简单的代码：

 public async Task<string> GetData(String labelName)
    {
        using (var client = new HttpClient())
        {
            var uri = new Uri(@"https://example.com/over/search_field?=search_label=" + labelName);

            var response = await client.GetAsync(uri).ConfigureAwait(false);
            var textResult = await response.Content.ReadAsStringAsync();
            return textResult;
        }
    }

在project.json中：

 {
"webroot": "wwwroot",
"version": "1.0.0-*",
"dependencies": {
  "Microsoft.AspNet.IISPlatformHandler": "1.0.0-beta8",
 "Microsoft.AspNet.Mvc": "6.0.0-beta8",
 "Microsoft.AspNet.Server.Kestrel": "1.0.0-beta8",
 "Microsoft.AspNet.StaticFiles": "1.0.0-beta8",

 "Microsoft.Framework.Logging": "1.0.0-beta8",
 "Microsoft.Framework.Logging.Console": "1.0.0-beta8",
 "Microsoft.Framework.Logging.Debug": "1.0.0-beta8",
 "Microsoft.Net.Http": "2.2.22"
  },
 "frameworks": {
  "dnx451": {
    "dependencies": {
       "Microsoft.AspNet.WebApi.Client": "5.2.3",
      "Microsoft.AspNet.WebApi.Owin": "5.2.3",
      "System.Net.Http": "4.0.1-beta-23409"


   },
   "frameworkAssemblies": {
     "System.Net": "4.0.0.0",
     "System.Net.Http": "4.0.0.0"
   }
 },
 "dnxcore50": { }
},

但是，当我尝试构建代码时，出现错误：


错误CS0246找不到类型或名称空间名称'HttpClient'（您是否缺少using指令或程序集引用？）


你能帮助我吗？如何解决这个错误？
我使用VS 2015和ASP MVC 6 Web API。
谢谢！

最佳答案

这对我有用。我在System.Net.Http部分中添加了dependencies并构建了项目（因此在DNX 4.5.1和DNX Core 5.0中都恢复了这个新的依赖关系）

"dependencies": {
    "Microsoft.AspNet.Diagnostics": "1.0.0-rc1-final",
    "Microsoft.AspNet.IISPlatformHandler": "1.0.0-rc1-final",
    "Microsoft.AspNet.Mvc": "6.0.0-rc1-final",
    "Microsoft.AspNet.Mvc.TagHelpers": "6.0.0-rc1-final",
    "Microsoft.AspNet.Server.Kestrel": "1.0.0-rc1-final",
    // Removed some dependencies for saving space:)
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0-rc1-final",
    "System.Net.Http": "4.0.1-beta-23409"
},
"frameworks": {
    "dnx451": { },
    "dnxcore50": {}
},

在以下运行时中进行了验证，并且工作正常。


coreclr-X86-1.0.0-rc1-update1
coreclr-X64-1.0.0-rc1-update1
clr-X86-1.0.0-rc1-update1
clr-X64-1.0.0-rc1-update1


此外，还需要确保具有using指令，该指令将在具有GetData方法的类文件中导入System.Net.Http命名空间。

using System.Net.Http;