使用SendGrid API(C#)批量发个性化邮件仅送达首个收件人问题求助

你的代码问题出在手动初始化msg.Personalizations为新List并直接添加项，这不符合SendGrid C# SDK的正确使用方式。SendGridMessage实例的Personalizations属性默认已经初始化了空列表，直接赋值会破坏SDK内部的状态管理逻辑，导致只有第一个个性化配置被处理。

修改后的代码 #

SendGridClient client = new SendGridClient(apiKey);
SendGridMessage msg = new SendGridMessage();
msg.SetFrom(new EmailAddress(from, fromName));
msg.Subject = subject;
msg.HtmlContent = "some content with replacement fields like [Verification Code] and [User Name]";
List<string> recipients = new List<string>();
recipients.Add("some address");
recipients.Add("second address");

// 移除手动初始化Personalizations的代码
for (int x = 0; x < recipients.Count; x++) {
    if (recipients[x].IndexOf("@") > -1) {
        Personalization personalization = new Personalization();
        personalization.Tos = new List<EmailAddress> { new EmailAddress(recipients[x]) };
        Dictionary<string, string> subs = new Dictionary<string, string>();
        subs.Add("[Verification Code]", "ABC123");
        subs.Add("[User Name]", "Mark");
        personalization.Substitutions = subs;
        // 使用SDK提供的AddPersonalization方法添加个性化配置
        msg.AddPersonalization(personalization);
        addressAdded = true;
    }
}
Response response = await client.SendEmailAsync(msg).ConfigureAwait(false);

关键说明 #

• 不要手动给msg.Personalizations赋值新的List，保留SDK默认初始化的集合即可。
• 必须使用msg.AddPersonalization()方法添加每个个性化配置，该方法会处理SDK内部的验证和状态维护，确保所有个性化项都被正确识别并发送。

内容的提问来源于stack exchange，提问作者nuander