c# - 更新gridview消失时的Gridview UpdatePanel

Question

我有一个显示用户数据的网格视图和一个项目超链接，单击时将填充下表中的数据以供管理员更新。

 <asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<fieldset>
    <div style="float: left;">
        <h2>
            Members</h2>
    </div>
    <div style="float: right; padding-right: 30px;">
        <a href="createmember.aspx">Create Member</a>
    </div>
    <div style="clear: both;" />
    <hr />
    <asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="Conditional">
    <ContentTemplate>
    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" BackColor="White"
        BorderColor="#CCCCCC" BorderStyle="None" DataKeyNames="UserID" BorderWidth="1px"
        CellPadding="4" ForeColor="Black" GridLines="Horizontal" Width="886px" EnableSortingAndPagingCallbacks="true">
        <Columns>
            <asp:BoundField DataField="FirstName" HeaderText="First Name" />
            <asp:BoundField DataField="LastName" HeaderText="Last Name" />
            <asp:BoundField DataField="email" HeaderText="Email" />

            <asp:TemplateField HeaderText="Action">
                <ItemTemplate>
                    <asp:HyperLink ID="HyperLink2" runat="server" NavigateUrl='<%# "~/member.aspx?UserID="+  DataBinder.Eval(Container.DataItem,"UserID")  %>'
                        Text='View'></asp:HyperLink>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>
    <br />

</ContentTemplate>
<Triggers>

            <div class="formlabel">
                Index :</div>
            <div class="formlabel">
                <asp:Label ID="userID" runat="server" Text=""></asp:Label></div>
            <br />
            <div class="formlabel">
                Login Name :</div>
            <asp:TextBox ID="username" runat="server" MaxLength="40"></asp:TextBox>
            <asp:RequiredFieldValidator ControlToValidate="username" ID="RequiredFieldValidator1"
                runat="server" ErrorMessage="Username can't be null" Display="None">
            </asp:RequiredFieldValidator>
            <cc1:ValidatorCalloutExtender ID="ValidatorCalloutExtender1" runat="server" TargetControlID="RequiredFieldValidator1" />
            <asp:CustomValidator ID="CustomValidator6" runat="server" ControlToValidate="username"
                Display="None" ErrorMessage="Username already exists." ClientValidationFunction="CheckUniqueness"
                OnServerValidate="UserNameExistsValidator_ServerValidate"></asp:CustomValidator>
            <cc1:ValidatorCalloutExtender ID="ValidatorCalloutExtender14" runat="server" PopupPosition="Right"
                TargetControlID="CustomValidator6">
            </cc1:ValidatorCalloutExtender>
            <br />
            <div class="formlabel">
                Password :</div>
            <asp:TextBox ID="password" runat="server" TextMode="Password"></asp:TextBox>
            <asp:RequiredFieldValidator ControlToValidate="password" ID="RequiredFieldValidator2"
                runat="server" ErrorMessage="Password can't be null" Display="None">
            </asp:RequiredFieldValidator>
            <cc1:ValidatorCalloutExtender ID="ValidatorCalloutExtender2" runat="server" TargetControlID="RequiredFieldValidator2">
            </cc1:ValidatorCalloutExtender>
            <br />
            <div class="formlabel">
                First Name :</div>
            <asp:TextBox ID="firstname" runat="server"></asp:TextBox>
            <asp:RequiredFieldValidator ControlToValidate="firstname" ID="RequiredFieldValidator3"
                runat="server" ErrorMessage="First Name can't be null" Display="None">
            </asp:RequiredFieldValidator>
            <cc1:ValidatorCalloutExtender ID="ValidatorCalloutExtender3" runat="server" TargetControlID="RequiredFieldValidator3">
            </cc1:ValidatorCalloutExtender>
            <br />
            <div class="formlabel">
                Last Name :</div>
            <asp:TextBox ID="lastname" runat="server"></asp:TextBox>
            <asp:RequiredFieldValidator ControlToValidate="lastname" ID="RequiredFieldValidator4"
                runat="server" ErrorMessage="Last Name can't be null" Display="None">
            </asp:RequiredFieldValidator>
            <cc1:ValidatorCalloutExtender ID="ValidatorCalloutExtender4" runat="server" TargetControlID="RequiredFieldValidator4">
            </cc1:ValidatorCalloutExtender>
            <br />
            <div class="formlabel">
                Email :</div>
            <asp:TextBox ID="email" runat="server"></asp:TextBox>
            <asp:RequiredFieldValidator ControlToValidate="lastname" ID="RequiredFieldValidator5"
                runat="server" ErrorMessage="Email can't be null" Display="None">
            </asp:RequiredFieldValidator>
            <cc1:ValidatorCalloutExtender ID="ValidatorCalloutExtender5" runat="server" TargetControlID="RequiredFieldValidator5">
            </cc1:ValidatorCalloutExtender>
            <asp:RegularExpressionValidator ID="REVEmail" runat="server" ControlToValidate="email"
                ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*" ErrorMessage="Invalid Email"
                Display="None"></asp:RegularExpressionValidator>
            <cc1:ValidatorCalloutExtender ID="REVEmail_ValidatorCalloutExtender" runat="server"
                TargetControlID="REVEmail">
            </cc1:ValidatorCalloutExtender>
            <br />

            <br />
            <asp:Label ID="msg" runat="server" Text=""></asp:Label>
            <br />
            <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Update" />
            <br />
        </fieldset>
    </ContentTemplate>
</asp:UpdatePanel>

以下是我的后端代码：

 if (Page.IsValid)
    {
        string id = Request.QueryString["UserID"];
        string firstnamevalue = firstname.Text;
        string lastnamevalue = lastname.Text;
        string emailvalue = email.Text;
        MySqlConnection connect = new MySqlConnection(connectionString);
        MySqlCommand command = connect.CreateCommand();

        command.CommandText = "Update user set Email = '" + emailvalue + "', FirstName ='" + firstnamevalue + "' , LastName ='" + lastnamevalue + "' WHERE UserID =" + id;
        try
        {

            connect.Open();
            command.Connection = connect;
            command.ExecuteNonQuery();
            GridView1.DataBind();
            UpdatePanel2.Update();
        }
        catch
        {
            msg.Text = "Error Occured";
        }
        finally
        {
            connect.Close();
        }

    }

当我尝试更新时，gridview 会消失，我可以知道我的代码是什么吗？