Note: These steps only work if max protocol version of your service is 3 or higher. Version 3 of OData introduced a new JSON format, and the WCF Data Services client only supports this JSON format. (Old JSON payloads have things like "__metadata"
at the top and "d":{...}
. In the new JSON format, you'll see things like "odata.metadata"
, "odata.type"
, etc.)
First, make sure you have version 5.1 or greater of the WCF Data Sevrices client library (Visual Studio ships with an older version) and an updated version of the tooling that makes "Add Service Reference" in Visual Studio work.
You can download the latest tools installer here: http://www.microsoft.com/en-us/download/details.aspx?id=35840.
Once you've installed that, I recommend upgrading to the latest version of the WCF Data Services client by issuing the following command in the NuGet package manager console:
Install-Package Microsoft.Data.Services.Client
Once you've upgraded to the latest client library, you should be able to use JSON in the client without a problem. Right click on your project in Visual Studio, select "Add Service Reference" and enter the URL of the metadata document of the service. In v5.1 and above, this will pull down the full model of the service, which is needed to support JSON.
"Add Service Reference" will auto-generate a subclass of DataServiceContext
. (You can see this generated code by selecting "Show All Files" in the solution explorer of Visual Studio and expanding the code behind the service reference.) For example, when I do "Add Service Reference" against http://services.odata.org/V3/OData/OData.svc/$metadata
, the client library generates a class called DemoService
. Use that derived class instead of DataServiceContext
directly, and you can just call .Format.UseJson()
. For example:
var context = new DemoService(new Uri("http://services.odata.org/V3/OData/OData.svc");
context.Format.UseJson();