问题描述

当我尝试添加用户控件时出现此错误

When I'm trying to add user control I got this error

Only one instance of a ScriptManager can be added to the page 

代码:

.ascx

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="VisaUserControl.ascx.cs" Inherits="Portal.VisaUserControl" %>
<%@ Register Assembly="BasicFrame.WebControls.BasicDatePicker" Namespace="BasicFrame.WebControls" TagPrefix="dp" %>
<asp:ScriptManager ID="scriptmanager1" runat="server"></asp:ScriptManager>
<div id="divreg" runat="server">
<table id="tbl" runat="server">
    <tr>
    <td>
        <asp:Label ID="lbl2" runat="server"></asp:Label>
    </td>
</tr>
<tr>
<td> Visa Number:</td>
<td><asp:TextBox ID="txtUser" Width="160px" runat="server"/></td>
<td> Country Name:</td>
<td><asp:DropDownList ID="dropCountry" Width="165px" runat="server"></asp:DropDownList></td>
</tr>
<tr>
<td> Type of Visa:</td>
<td><asp:DropDownList ID="dropVisa" Width="165px" runat="server" OnSelectedIndexChanged="dropVisa_SelectedIndexChanged"></asp:DropDownList></td>
<td> Type of Entry:</td>
<td><asp:DropDownList ID="dropEntry" Width="165px" runat="server"></asp:DropDownList></td>
</tr>
<tr>
<td> Expiry Date</td>
    <td><asp:TextBox ID="txtDate" runat="server"></asp:TextBox>
        <ajaxToolkit:CalendarExtender ID="CalendarExtender1" runat="server" 
                          TargetControlID="txtDate" PopupButtonID="Imgbtnfromdate" Format="dd/MM/yyyy">
                      </ajaxToolkit:CalendarExtender>
    </td>
<td>
<asp:Button ID="btnRemove" Text="Remove" runat="server" OnClick="btnRemove_Click" />
</td>
</tr>
</table>
</div>

.aspx.cs

  protected override void LoadViewState(object savedState)
    {
        base.LoadViewState(savedState);

        GenerateControls();
    }



    private void GenerateControls()
    {
        foreach (string i in NoOfControls)
        {
            VisaUserControl ctrl = (VisaUserControl)Page.LoadControl("VisaUserControl.ascx");
            ctrl.ID = i;
            this.rpt1.Controls.Add(ctrl);
        }
    }

问题来了

    protected void btnAddVisa_Click(object sender, EventArgs e)
    {

        List<string> temp = null;
        var uc = (VisaUserControl)this.LoadControl(@"VisaUserControl.ascx");

        string id = Guid.NewGuid().ToString();
        uc.ID = id;

        temp = NoOfControls;
        temp.Add(id);
        NoOfControls = temp;
        rpt1.Controls.Add(uc);
    }

在下图中，如果单击添加按钮出现此错误

In the below image if Click add button I got this error

有什么想法吗?提前致谢

Any ideas? Thanks in advance

推荐答案

尝试从用户控件中删除 ScriptManager.

Try removing ScriptManager from user control.

您肯定在 .aspx 页面或 MasterPage 的其他位置添加了 ScriptManager.检查这些页面.

You have definitely added a ScriptManager somewhere else in your .aspx Page or MasterPage. Check these pages.

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>

如果您在母版页上需要 ScriptManager，在这种情况下，用户控件中不需要有 ScriptManager.请遵守以下规则:

In case you require ScriptManager on Master page,In this case, there is NO need to have a ScriptManager in userControl. Follow below rules:

• 确保母版页上只有一个 <asp:Scriptmanager>.
• 确保在每个可能需要脚本管理器的内容页面上也只有一个 <asp:ScriptManagerProxy>

以下是 MSDN 谈到 ScriptManager 控制.

Below is what MSDN says about ScriptManager Control.

只能将 ScriptManager 控件的一个实例添加到页.页面可以直接或间接包含控件在嵌套组件内，例如用户控件、内容页面母版页或嵌套母版页.如果页面已经包含ScriptManager 控件，但需要嵌套或父组件ScriptManager 控件的附加功能，该组件可以包括一个 ScriptManagerProxy 控件.例如，ScriptManagerProxy 控件使您能够添加脚本和服务特定于嵌套组件

Only one instance of the ScriptManager control can be added to the page. The page can include the control directly, or indirectly inside a nested component such as a user control, content page for a master page, or nested master page. If a page already contains a ScriptManager control, but a nested or parent component needs additional features of the ScriptManager control, the component can include a ScriptManagerProxy control. For example, the ScriptManagerProxy control enables you to add scripts and services that are specific to nested components

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