ASP电子邮件客户端错误，GridView和复选框

Question

我在执行以下代码时遇到问题，我正在创建一个电子邮件系统，我可以通过单击GridView中的复选框选择多个电子邮件。选择想要的电子邮件并点击发送按钮后，我会收到以下错误

索引超出范围。必须是非负的，并且小于收藏的大小。 参数名称：索引

描述：执行当前Web请求期间发生了一个未经治疗的异常。请查看堆栈跟踪，以获取有关该错误以及代码中何处的更多信息。

异常详细信息：System.ArgumentOutOfrangeException：索引超出范围。必须是非负的，并且小于收藏的大小。 参数名称：索引

这是我下面的代码任何帮助都将受到赞赏

protected void send_Click(object sender, EventArgs e)
{
        //Array list to hold selected email ids
        ArrayList emailArray = new ArrayList();
        //Looping through rows of GridView
        foreach (GridViewRow item in GridView1.Rows)
        {
            //Creating checkbox object using the find control method
            CheckBox cb = (CheckBox)item.Cells[1].FindControl("CheckBox1");
            //CheckBox cb = (CheckBox)item.FindControl("CheckBox1");
            //Checking whether checkbox is checked or not
            if (cb.Checked)
            {
                //If checked Adding email id to Arraylist
                emailArray.Add(GridView1.DataKeys[item.RowIndex]["email"].ToString());
            }
        }
        //Looping through the email id list
        foreach (string email in emailArray)
        {
            MailMessage msg = new MailMessage();
            msg.From = new MailAddress("[e-mail]");
            msg.To.Add(email);
            msg.Subject = subjecttext.Text;
            msg.Body = TextBox1.Text;
            SmtpClient smt = new SmtpClient("smtp.gmail.com", 587);
            smt.Credentials = new System.Net.NetworkCredential("[e-mail]", "xxxxxxxxx");
            smt.EnableSsl = true;
            smt.Send(msg);
            //}
        }
        emailsent.Text = "Email has been sent Successfully";
    }
}  
<asp:GridView ID="GridView1" runat="server" Visible="true"
    CssClass="mydatagrid" EmptyDataText="No Students Enrolled on this Module" 
    EmptyDataRowStyle-BorderWidth="0px" PagerStyle-CssClass="pager" 
    HeaderStyle-CssClass="header" RowStyle-CssClass="rows"   
    DataSourceID="displayemail">  
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:CheckBox ID="CheckBox1" runat="server" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="email" HeaderText="email" SortExpression="name" />
    </Columns>
</asp:GridView>

Answer 1

您缺少的是设置GridView的DataKeyName属性。您的GridView应如下更改。

<asp:GridView ID="GridView1" runat="server" Visible="true"
    CssClass="mydatagrid" EmptyDataText="No Students Enrolled on this Module" 
    EmptyDataRowStyle-BorderWidth="0px" PagerStyle-CssClass="pager" 
    HeaderStyle-CssClass="header" RowStyle-CssClass="rows"   
    DataSourceID="displayemail" DataKeyNames="email">  
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:CheckBox ID="CheckBox1" runat="server" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="email" HeaderText="email" SortExpression="name" />
    </Columns>
</asp:GridView>