如何在.NET Core 3.1和C#中使用SendGrid发送邮件时添加CC或BCC

你可以通过扩展现有方法，添加CC、BCC参数并调用SendGridMessage的AddCc、AddBcc方法实现需求。以下是修改后的完整代码：

public async Task<Response> Send(string ToUser, string Subject, string TextContent, string HtmlContent, 
                                 string ccUsers = null, string bccUsers = null, 
                                 string base64context = null, string filename = "")
{
    string apiKey = AppConfiguration.SendGridApiKey;
    SendGridClient client = new SendGridClient(apiKey);
    EmailAddress from = new EmailAddress(AppConfiguration.SendGridFromEmail, AppConfiguration.SendGridFromName);
    EmailAddress toMail = new EmailAddress(ToUser);
    SendGridMessage msg = MailHelper.CreateSingleEmail(from, toMail, Subject, TextContent, HtmlContent);

    // 添加抄送（CC）地址，支持逗号分隔多个邮箱
    if (!string.IsNullOrWhiteSpace(ccUsers))
    {
        foreach (var cc in ccUsers.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries))
        {
            msg.AddCc(new EmailAddress(cc.Trim()));
        }
    }

    // 添加密送（BCC）地址，支持逗号分隔多个邮箱
    if (!string.IsNullOrWhiteSpace(bccUsers))
    {
        foreach (var bcc in bccUsers.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries))
        {
            msg.AddBcc(new EmailAddress(bcc.Trim()));
        }
    }

    if(!string.IsNullOrWhiteSpace(base64context) && !string.IsNullOrWhiteSpace(filename))
    {
        msg.AddAttachment(filename, base64context);
    }

    return await client.SendEmailAsync(msg);
}

关键修改说明： #

• 新增可选参数ccUsers和bccUsers，支持传入逗号分隔的多邮箱字符串（例如"user1@example.com,user2@example.com"）
• 通过Split拆分多邮箱字符串，遍历添加到CC/BCC列表，并用Trim处理地址中的空格
• 调用SendGridMessage内置的AddCc、AddBcc方法完成抄送、密送地址的添加

调用示例：

await Send("target@example.com", "测试主题", "纯文本内容", "<h1>HTML内容</h1>", 
           ccUsers: "cc1@example.com,cc2@example.com", 
           bccUsers: "bcc@example.com");

内容的提问来源于stack exchange，提问作者Arjun Bhatt