C# 回发后隐藏div

我在更新面板中使用文件上载，所以我将PostBackTrigger添加到btnsubmit以使其工作

<asp:PostBackTrigger ControlID="btnsubmit" />

b提交代码

string imgPath;
protected void btnsubmit_Click(object sender, EventArgs e)
{
    try
    {
         if (imgup.HasFile)
         {
            string imgName = imgup.FileName.ToString();
            imgup.SaveAs(Server.MapPath("Images/") + imgName);
            imgPath = "Images/" + imgName;
         }
        string msg=i.AddItem(txtitemcode.Text,imgPath,DateTime.Now.ToShortDateString());
        if (msg == "true")
        {
            gridItem.DataSource = i.GetItems();
            gridItem.DataBind();
            MultiView1.ActiveViewIndex = 0;
            divtrue.Visible = true;
        }
        else
        {
            MultiView1.ActiveViewIndex = 0;
            divfalse.Visible = true;
        }
    }
    catch (Exception ex)
    {
        Response.Write("Error: " + ex.Message);
    }
}

更新面板

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
    <ContentTemplate>
        <asp:MultiView ID="MultiView1" runat="server" ActiveViewIndex="0">
            <asp:View ID="View1" runat="server">
                <div class="alert alert-success" runat="server" id="divtrue">
                    <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
                    <strong>Success!</strong>
                    <asp:Label ID="lbltrue" runat="server" Text="Item added successfully."></asp:Label>
                </div>
                <div class="alert alert-danger" runat="server" id="divfalse">
                    <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
                    <strong>Error!</strong>
                    <asp:Label ID="lblfalse" runat="server" Text="Item not aadded please try again."></asp:Label>
                </div>
            </asp:View>
<asp:View ID="View2" runat="server">
        <%--Adding form %>

                        <div class="btn-group">
                            <asp:Button ID="btnsubmit" runat="server" OnClick="btnsubmit_Click" class="btn btn-primary" Text="Submit" Width="100px" ValidationGroup="g1" />
                        </div>
            </asp:View>
        </asp:MultiView>
    </ContentTemplate>
    <Triggers>
        <asp:PostBackTrigger ControlID="btnsubmit" />
    </Triggers>
</asp:UpdatePanel>

成功
错误

尝试使用以下方法：

divfalse.Attributes.Add("style", "display:none;");

---

你的div代码应该在更新面板内发布你的更新面板代码。Nazir Ullah在更新面板内将UpdateMode设置为

始终

Akash Amin无任何更改

divfalse.Attributes.Add("style", "display:none;");