Question

在基于Web的ASP.NET建议框程序中，管理员将能够使用所有者的用户名查看GridView控件中列出的所有建议。在GridView的最后一列中，状态将列在那里。当管理员点击其中一个建议的状态时，将出现一个新的弹出窗口（asp.net ajax ModalPopUpExtender），列出所有可能的状态，例如：actioned，approved ...等。当Admin选择其中一个状态，建议的状态将在数据库中更新。一切正常。我现在要做的是当用户更新任何建议的状态时，将向所有者发送关于更新其建议状态的电子邮件通知。

我已经编写了Mail函数，但我不知道它为什么不发送任何电子邮件，我在调试代码时收到此错误：

使用未分配的本地变量'description'

我已将其分配给数据库中[Description]列的值，但我不知道为什么会出现此错误。

有人可以帮我这个吗？

我真的很难获得更新建议的用户名。仅供参考，我有以下数据库设计：

Employee Table: Username, Name... 
SafetySuggestionsLog: ID, Title, Description, Username, StatusID 
SafetySuggestionsStatus: ID, Status

ASP.NET代码：

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
        <asp:GridView ID="GridView1" runat="server" AllowPaging="True" 
                        AllowSorting="True" AutoGenerateColumns="False" DataKeyNames="ID" 
                        width="900px" CssClass="mGrid" 
                        DataSourceID="SqlDataSource1" 
                        OnRowDataBound="GridView1_RowDataBound">
            <AlternatingRowStyle BackColor="White" ForeColor="#284775" CssClass="alt" />
            <HeaderStyle Font-Bold = "True" ForeColor="Black" Height="20px"/> 
            <Columns>
                <asp:BoundField DataField="ID" HeaderText="No." InsertVisible="False" 
                    ReadOnly="True" SortExpression="ID" />
                <asp:BoundField DataField="Title" HeaderText="Title" SortExpression="Title" />
                <asp:BoundField DataField="Description" HeaderText="Description" 
                    SortExpression="Description" />
                <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                <asp:BoundField DataField="Username" HeaderText="Username" 
                    SortExpression="Username" />
                <asp:BoundField DataField="DivisionShortcut" HeaderText="Division" 
                    SortExpression="DivisionShortcut" />
                <asp:BoundField DataField="Type" HeaderText="Type" SortExpression="Type" />

                <%-- This to make status be opened and edited through the Ajax ModalPopUp Window --%>
                <asp:TemplateField HeaderText="Status">
                    <ItemTemplate>
                        <asp:LinkButton runat="server" ID="lnkSuggestionStatus" Text='<%#Eval("Status")%>'
                                        OnClick="lnkSuggestionStatus_Click">
                        </asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>

                <%--<asp:HyperLinkField HeaderText="Status" 
                    SortExpression="Status" />--%>
            </Columns>
            <RowStyle HorizontalAlign="Center" />
        </asp:GridView>

        <asp:Button runat="server" ID="btnModalPopUp" style="display:none" />

        <AjaxToolkit:ModalPopUpExtender ID="modalPopUpExtender1"
                                        runat="server" 
                                        TargetControlID="btnModalPopUp" 
                                        PopupControlID="pnlPopUp" 
                                        BackgroundCssClass="popUpStyle"
                                        PopupDragHandleControlID="panelDragHandle" 
                                        OkControlID="OKButton">
        </AjaxToolkit:ModalPopUpExtender>

        <asp:HiddenField ID="HiddenField1" runat="server"/>

        <asp:Panel runat="server" ID="pnlPopUp" CssClass="popUpStyle">

                    <asp:RadioButtonList ID="StatusList" runat="server" RepeatColumns="1" RepeatDirection="Vertical"
                                            RepeatLayout="Table" TextAlign="Right" DataSourceID="SuggestionStatusDataSource"
                                            DataTextField="Status" DataValueField="ID">
                        <asp:ListItem id="option1" runat="server" Value="ACTIONED" />
                        <asp:ListItem id="option2" runat="server" Value="APPROVED" />
                        <asp:ListItem id="option3" runat="server" Value="PENDING" />
                        <asp:ListItem id="option4" runat="server" Value="TRANSFERRED" />
                    </asp:RadioButtonList>
                    <asp:SqlDataSource ID="SuggestionStatusDataSource" runat="server"
                                        ConnectionString="<%$ ConnectionStrings:testConnectionString %>"
                                        SelectCommand="SELECT * FROM [SafetySuggestionsStatus]"></asp:SqlDataSource>

                    <asp:Button ID="confirmButton" runat="server" Text="Confirm" 
                                OnClientClick="javascript:return confirm('Are you sure you want to send an email notification about the safety suggestion to the owner?')" 
                                OnClick="btnSendStatus_Click" />

            <asp:Button ID="OKButton" runat="server" Text="Close" />
        </asp:Panel>
        </ContentTemplate>
        </asp:UpdatePanel>

代码隐藏：

protected void lnkSuggestionStatus_Click(object sender, EventArgs e)
    {
        LinkButton lnkSuggestionStatus = sender as LinkButton;

        //var safetySuggestionsId = 

        //get reference to the row selected 
        GridViewRow gvrow = (GridViewRow)lnkSuggestionStatus.NamingContainer;

        //set the selected index to the selected row so that the selected row will be highlighted
        GridView1.SelectedIndex = gvrow.RowIndex;

        //This HiddenField used to store the value of the ID
        HiddenField1.Value = GridView1.DataKeys[gvrow.RowIndex].Value.ToString();
        //ViewState["Username"] = gvrow.Cells[4].Text;

        //show the modalPopUp
        modalPopUpExtender1.Show();
    }

    public void btnSendStatus_Click(object sender, EventArgs e) {
        //get the ID of the selected suggestion/row
        var statusID = StatusList.SelectedValue;
        var safetySuggestionsID = HiddenField1.Value;

        string connString = "Data Source=localhost\\sqlexpress;Initial Catalog=psspdbTest;Integrated Security=True";
        //For updating the status of the safety suggestion
        string updateCommand = "UPDATE SafetySuggestionsLog SET StatusID= @statusID where ID=@SafetySuggestionsID";
        using (SqlConnection conn = new SqlConnection(connString))
        {
            conn.Open();
            using (SqlCommand cmd = new SqlCommand(updateCommand, conn))
            {
                cmd.Parameters.AddWithValue("@statusID", Convert.ToInt32(statusID));
                cmd.Parameters.AddWithValue("@SafetySuggestionsID", Convert.ToInt32(HiddenField1.Value));
                cmd.ExecuteNonQuery();
            }
            //reset the value of hiddenfield
            HiddenField1.Value = "-1";
        }

        GridView1.DataBind();


        SendSuggestionStatusToUser(safetySuggestionsID);
    }

    protected void SendStatusByEmail(string toAddresses, string fromAddress, string MailSubject, string MessageBody, bool isBodyHtml)
    {
        SmtpClient sc = new SmtpClient("MAIL.Aramco.com");
        try
        {
            MailMessage msg = new MailMessage();
            msg.From = new MailAddress("pssp@aramco.com", "PMOD Safety Services Portal (PSSP)");

            // In case the mail system doesn't like no to recipients. This could be removed
            //msg.To.Add("pssp@aramco.com");

            msg.Bcc.Add(toAddresses);
            msg.Subject = MailSubject;
            msg.Body = MessageBody;
            msg.IsBodyHtml = isBodyHtml;
            sc.Send(msg);
        }
        catch (Exception ex)
        {
            throw ex;
        }

    }

    protected void SendSuggestionStatusToUser(string suggestionID)
    {
        string connString = "Data Source=localhost\\sqlexpress;Initial Catalog=psspdbTest;Integrated Security=True";

        string safetySuggestionID = suggestionID.ToString();
        //string username = ViewState["Username"].ToString();

        //The following connection is to get the username of the suggestion Owner
        //and append (@aramco.com) to it.
        using (SqlConnection conn = new SqlConnection(connString))
        {
            var sbEmailAddresses = new System.Text.StringBuilder(2000);

            //initiate the varibles that will be retreived from the database
            string username;
            string description;
            string status;

            // Open DB connection.
            conn.Open();

            string cmdText2 = @"SELECT Username, Description, Status FROM dbo.SafetySuggestionsLog SSL INNER JOIN SafetySuggestionsStatus SSS
                                ON (SSL.StatusID = SSS.ID) WHERE (SSL.ID = @safetySuggestionID)";
            using (SqlCommand cmd = new SqlCommand(cmdText2, conn))
            {
                cmd.Parameters.AddWithValue("@SafetySuggestionID", Convert.ToInt32(HiddenField1.Value));
                SqlDataReader reader = cmd.ExecuteReader();
                if (reader != null)
                {
                    if (reader.Read())
                    {
                        username = reader["Username"].ToString();
                        description = reader["Description"].ToString();
                        status = reader["Status"].ToString();
                        sbEmailAddresses.Append(username).Append("aramco.com");
                    }
                }

                var sEMailAddresses = sbEmailAddresses.ToString();
                string body = @"Good day, &lt;br /&gt;&lt;br /&gt;
                                <b> We just would like to notify you that your following safety suggestion: </b>"
                                    + description +
                                    @"&lt;br /&gt;&lt;br /&gt;
                            has been.
                            &lt;br /&gt; &lt;br /&gt;&lt;br /&gt; &lt;br /&gt;
                            This email was generated using the &lt;a href='http://pmv/pssp/Default.aspx'&gt;PMOD Safety Services Portal (PSSP) &lt;/a&gt;. 
                            Please do not reply to this email.
                            ";
                SendStatusByEmail(sbEmailAddresses.ToString(), "", "Notification of Your Safety Suggestion", body, true);
                sbEmailAddresses.Clear();
                reader.Close();


            }

            conn.Close();
        }
    }

注意：我知道我不应该在这里发布冗长的代码，但是因为我想向您解释我的工作并得到您的帮助。

更新

我修改了关于将变量赋值为NULL的代码，当我调试代码时，我发现读者无法工作，并且没有阅读以下内容：

if (reader != null)
                {
                    if (reader.Read())
                    {
                        username = reader["Username"].ToString();
                        description = reader["Description"].ToString();
                        status = reader["Status"].ToString();
                        sbEmailAddresses.Append(username).Append("@aramco.com");
                    }
                }

更新2：

在SendSuggestionStatusToUser(string suggestionID)方法中，我将断点添加到以下行：

string safetySuggestionID = suggestionID.ToString();

我将断点添加到以下行：

cmd.Parameters.AddWithValue("@safetySuggestionID", Convert.ToInt32(HiddenField1.Value));

我发现，对于第一个，safetySuggestionID从传递的值中获取数据。但是，对于第二个，(HiddenField1.Value)的值为-1，我不知道为什么。另外，我为以下每一行添加了断点：

SqlDataReader reader = cmd.ExecuteReader();
                if (reader != null)
                {
                    if (reader.Read())
                    {
                        username = reader["Username"].ToString();
                        description = reader["Description"].ToString();
                        status = reader["Status"].ToString();
                        sbEmailAddresses.Append(username).Append("@aramco.com");
                    }
                }

在调试它们时，调试器没有通过它们。它直接进入

var sEMailAddresses = sbEmailAddresses.ToString();

我不知道为什么。任何的想法？你能帮我吗？

Answer 1

问题在于username函数中的变量description，status和SendSuggestionStatusToUser在您使用时并非明确分配使用它们。

也就是说，如果reader == null他们不有值。

由于使用description稍后构建body的值，因此可能为null（并且从未分配过）。这就是错误的意思。

一个简单的改变是明确地将它们分配给null或空字符串：

string username = null;
string description = null;
string status = string.Empty;

更新

我现在已经注意到你是如何构建你的电子邮件地址的：

sbEmailAddresses.Append(username).Append("aramco.com");

除非username以@结尾，否则不会生成有效的电子邮件地址。电子邮件地址之间也没有分隔符，所以我不知道这是如何工作的。

Answer 2

如果您的阅读器为空或未返回任何记录，则您的用户名，描述，状态和sbEmailAddress将为空值。

C＃Mail：为什么这个功能无法发送电子邮件？

2 个答案: