MVC4 獲取IP

private string GetClientIp(HttpRequestMessage request)
{
    if (request.Properties.ContainsKey("MS_HttpContext"))
    {
        return ((HttpContextWrapper)request.Properties["MS_HttpContext"]).Request.UserHostAddress;
    }
    else if (request.Properties.ContainsKey(RemoteEndpointMessageProperty.Name))
    {
        RemoteEndpointMessageProperty prop;
        prop = (RemoteEndpointMessageProperty)this.Request.Properties[RemoteEndpointMessageProperty.Name];
        return prop.Address;
    }
    else
    {
        return null;
    }
}