How to call wcf service using ajax - asp.net

Question

I'm trying to call a WCF service from ajax call. This is my ajax call:
$j.ajax(
{
type: "POST",
contentType: "application/json; charset=utf-8",
dataType: "json",
context: this,
async: false,
url: appServicePath + "Student/GetRolesByUserId",
data: JSON.stringify({ "userId": userId }),
success: this.getRolesByIdResponse,
error: this.getRolesByIdFailure
}
);
when I test my service using Fiddler I'm able to get the roles of the user that I'm passing its value from ajax but when I call the service from my application I get an error: 405 Method Not Allowed.
What am I doing wrong?

Answer 1

According to your description, I think this problem is due to cross-domain, the problem generates an OPTIONS request, So the method is not allowed. If you put the script in the same domain as the webservice, you won't have this problem.
Here is Http 405 method document.
https://www.rfc-editor.org/rfc/rfc7231#section-6.5.5
You now need to turn on cross-domain support for a WCF application hosted on the web server side.
Web.config
<system.webServer>
<httpProtocol>
<customHeaders>
<add name="Access-Control-Allow-Origin" value="*"/>
<add name="Access-Control-Allow-Headers" value="content-type" />
<add name="Access-Control-Allow-Methods" value="GET,POST,PUT,DELETE,OPTIONS" />
</customHeaders>
</httpProtocol>
</system.webServer>
Global.asax
protected void Application_BeginRequest(object sender, EventArgs e)
{
if (Request.Headers.AllKeys.Contains("Origin")&&Request.HttpMethod=="OPTIONS")
{
Response.End();
}
}
Feel free to contact me if you have any questions.