要通過ONVIF控制云臺，首先需要使用ONVIF協議與攝像頭進行通信。下面是一個簡單的示例代碼，演示如何使用C#語言通過ONVIF控制云臺：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ServiceModel;
using System.ServiceModel.Discovery;
using System.ServiceModel.Description;
using System.ServiceModel.Channels;

namespace ONVIFControl
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                // Create a discovery client to find ONVIF devices on the network
                DiscoveryClient discoveryClient = new DiscoveryClient(new UdpDiscoveryEndpoint());
                FindCriteria findCriteria = new FindCriteria(typeof(PTZBinding), new MetadataSet());
                findCriteria.Duration = TimeSpan.FromSeconds(10);
                FindResponse findResponse = discoveryClient.Find(findCriteria);

                // Get the endpoint address of the first device found
                EndpointAddress endpointAddress = findResponse.Endpoints[0].Address;

                // Create a PTZ client to control the PTZ functions of the device
                PTZClient ptzClient = new PTZClient(new CustomBinding(new TextMessageEncodingBindingElement(), new HttpTransportBindingElement()), endpointAddress);

                // Get the PTZ configuration of the device
                PTZConfiguration[] ptzConfigurations = ptzClient.GetConfigurations();
                string profileToken = ptzConfigurations[0].token;

                // Perform PTZ operations on the device
                ptzClient.ContinuousMove(profileToken, new PTZSpeed { PanTilt = new Vector2D { x = 1, y = 1 } }, null);

                Console.WriteLine("PTZ control successful");
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error: " + ex.Message);
            }
        }
    }
}

在這個示例代碼中，我們首先創建一個DiscoveryClient對象，用于查找網絡上的ONVIF設備。然后，我們創建一個PTZClient對象，用于控制PTZ功能。通過調用PTZClient的方法，我們可以獲取設備的PTZ配置信息，并執行PTZ操作，比如連續移動云臺。最后，我們將控制結果輸出到控制臺。

請注意，這只是一個簡單的示例代碼，實際中可能需要根據攝像頭的具體型號和功能進行調整。另外，需要確保設備支持ONVIF協議，并且已經正確配置了網絡連接和權限。