1. 在ASP.NET MVC项目中添加System.Net和System.Net.Mail的命名空间。
2. 在Startup文件中添加以下代码，以更改发送者电子邮件：

public void ConfigureServices(IServiceCollection services)
{
    //...
    services.AddTransient();
    services.Configure(Configuration);
    //...
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    //...
    var emailSender = app.ApplicationServices.GetService();
    EmailSender.SetEmailSenderSettings(Configuration.GetSection("EmailSenderSettings").Get());
    //...
}

3. 为IEmailSender接口创建一个EmailSender类并在其中实现SendEmailAsync方法。您可以在该类中使用SmtpClient类来更改发送者来源：

public class EmailSender : IEmailSender
{
    private readonly EmailSenderSettings _emailSenderSettings;

    public EmailSender(IOptions emailSenderSettings)
    {
        _emailSenderSettings = emailSenderSettings.Value;
    }

    public async Task SendEmailAsync(string email, string subject, string message)
    {
        using (var client = new SmtpClient())
        {
            client.Host = _emailSenderSettings.Host;
            client.Port = _emailSenderSettings.Port;
            client.EnableSsl = _emailSenderSettings.EnableSsl;
            client.UseDefaultCredentials = false;
            client.Credentials = new NetworkCredential(_emailSenderSettings.Username, _emailSenderSettings.Password);

            using (var emailMessage = new MailMessage())
            {
                emailMessage.From = new MailAddress(_emailSenderSettings.SenderEmail, "新的发送者名称");
                emailMessage.To.Add(email);
                emailMessage.Subject = subject;
                emailMessage.Body = message;
                emailMessage.IsBodyHtml = true;

                await client.SendMailAsync(emailMessage);
            }
        }
    }
}

4. 在appsettings.json文件中添加以下内容，以指定您的SMTP服务器设置：

{
  "EmailSenderSettings": {
    "Host": "smtp.example.com",
    "Port": 587,
    "EnableSsl": true,
    "Username": "yourusername",
    "