方法一：

在c#里执行cmd命令，net start/stop mssqlserver

方法二：

// 使用 Windows 服务控制器来启动或停止服务
using System;
using System.Windows.Forms;
using System.ServiceProcess;
class Test : Form
{
Test()
{
Button btn1 = new Button();
btn1.Parent = this;
btn1.Text = "启动 SQL Server";
btn1.Tag = "START";
btn1.Left = 10;
btn1.Width = 120;
btn1.Click += new EventHandler(BtnClick);
Button btn2 = new Button();
btn2.Parent = this;
btn2.Text = "停止 SQL Server";
btn2.Tag = "STOP";
btn2.Left = btn1.Right + 10;
btn2.Width = 120;
btn2.Click += new EventHandler(BtnClick);
}
void BtnClick(object sender, EventArgs e)
{
string s = (sender as Button).Tag.ToString();
ServiceController sc = new ServiceController("MSSQLSERVER");
if (s == "START" && sc.Status.Equals(ServiceControllerStatus.Stopped))
{
sc.Start();
}
if (s == "STOP" && !sc.Status.Equals(ServiceControllerStatus.Stopped))
{
sc.Stop();
}
}
static void Main()
{
Application.Run(new Test());
}
}