我认为你需要的是一个调度程序而不是线程，请查看：自动发送电子邮件每天在特定时间使用C＃和VB.Net中的Windows服务 [ ^ ]

在我看来，使用 Windows任务计划 r是一个更好的选择。

hai

i want send mail to my client at everyday 10.00 pm..
how to finish this task using thread in c# WinForm

What I have tried:

Thread thread = new Thread(new ThreadStart(SendMail));
thread.Start();

I think what you need is a scheduler not thread, check this out: Automatically send emails daily at specific time using Windows Service in C# and VB.Net[^]

In my humble opinion, using the Windows Task Scheduler is a better option.