c# - 给定的键不在字典中

Question

我接手了一个项目，在 .Net 4.0 项目中尝试找回丢失的密码时，该项目给用户带来了上述错误。我一步一步找到了问题所在，但问题是，生成的值似乎是正确的，所以我不知道为什么会发生错误。提前感谢任何可以查看以下代码并帮助我找出修复方法的人。让我知道是否需要更多信息。我查看了所有我能找到的东西，但没有任何东西给我可以使用的线索。问题是我无法追踪键/值组合应该输入的位置，也不知道一旦我添加了它。代码如下。

我在 http://forums.asp.net/t/1926444.aspx/1?given+key+was+not+present+in+the+dictionary 发表了类似的讨论但那里没有人知道如何帮助我。

void EmailUser(User user)
{
    user.ChangePasswordID = Guid.NewGuid();
    user.Save();
    MailMessage email = new MailMessage();
    //problem line below
    email.From = new MailAddress(Settings.LostPasswordEmailFrom);
    email.To.Add(new MailAddress(uxEmail.Text));
    email.Subject = Settings.LostPasswordSubject;
    email.Body = EmailTemplateService.HtmlMessageBody(EmailTemplates.MembershipPasswordRecovery, new { Body = Settings.LostPasswordText, BeginRequired = "", EndRequired = "", UserName = user.Name, GUID = user.ChangePasswordID.ToString() });
    email.IsBodyHtml = true;
    SmtpClient client = new SmtpClient();
    client.Send(email);

    uxSuccessPH.Visible = true;
    uxQuestionPanel.Visible = false;
    uxUserInfoPanel.Visible = false;
    uxUserNameLabelSuccess.Text = uxEmail.Text;
}

/// <summary>
/// The address that the lost password email will be sent from
/// </summary>
public static string LostPasswordEmailFrom
{
    get
    {
        if (String.IsNullOrEmpty(SiteSettings.GetSettingKeyValuePair()["LA_MembershipProvider_lostPasswordEmailFrom"]))
            return Globals.Settings.FromEmail;
        return SiteSettings.GetSettingKeyValuePair()["LA_MembershipProvider_lostPasswordEmailFrom"];
    }
}

Answer 1

当您调用 SiteSettings.GetSettingKeyValuePair()["LA_MembershipProvider_lostPasswordEmailFrom"]) 时，如果没有名为 LA_MembershipProvider_lostPasswordEmailFrom 的 key ，您将得到 “The given key was not存在于字典中” 错误。您可以做的是，先检查键是否存在，然后再获取值。你可以按照下面的方式做

public static string LostPasswordEmailFrom
{
    get
    { 
        var kvp = SiteSettings.GetSettingKeyValuePair();

        if (kvp == null || !kvp.ContainsKey("LA_MembershipProvider_lostPasswordEmailFrom"))
            return Globals.Settings.FromEmail;
        return kvp["LA_MembershipProvider_lostPasswordEmailFrom"];
    }
}