Can't find how to use HttpContent

问题:

I am trying to use HttpContent:

HttpContent myContent = HttpContent.Create(SOME_JSON);

...but I am not having any luck finding the DLL where it is defined.

First, I tried adding references to Microsoft.Http as well as System.Net, but neither is in the list. I also tried adding a reference to System.Net.Http but the HttpContent class is not available.

So, can anyone tell me where I can find the HttpContent class?

回答1:

The class is listed as being present in the System.Net.Http assembly. Note that this class is new for .NET 4.5, so you need to be using that version of the BCL.

回答2:

Just use...

var stringContent = new StringContent(jObject.ToString());
var response = await httpClient.PostAsync("http://www.sample.com/write", stringContent);

Or,

var stringContent = new StringContent(JsonConvert.SerializeObject(model), Encoding.UTF8, "application/json");
var response = await httpClient.PostAsync("http://www.sample.com/write", stringContent);

回答3:

To take 6footunder's comment and turn it into an answer, HttpContent is abstract so you need to use one of the derived classes:

回答4:

For JSON Post:

var stringContent = new StringContent(json, Encoding.UTF8, "application/json");
var response = await httpClient.PostAsync("http://www.sample.com/write", stringContent);

Non-JSON:

var stringContent = new FormUrlEncodedContent(new[]
{
    new KeyValuePair<string, string>("field1", "value1"),
    new KeyValuePair<string, string>("field2", "value2"),
});
var response = await httpClient.PostAsync("http://www.sample.com/write", stringContent);

https://blog.pedrofelix.org/2012/01/16/the-new-system-net-http-classes-message-content/

回答5:

While the final version of HttpContent and the entire System.Net.Http namespace will come with .NET 4.5, you can use a .NET 4 version by adding the Microsoft.Net.Http package from NuGet

回答6:

I'm pretty sure the code is not using the System.Net.Http.HttpContent class, but instead Microsoft.Http.HttpContent. Microsoft.Http was the WCF REST Starter Kit, which never made it out preview before being placed in the .NET Framework. You can still find it here: http://aspnet.codeplex.com/releases/view/24644

I would not recommend basing new code on it.

回答7:

The System.Net.Http namespace (where HttpContent class resides) is new to .Net 4.5, are you using a VS2012 RC?

Otherwise, you wouldn't have access to this.