C# – How to get ScriptManager to work with ScriptmanagerProxy

asp.netcscriptmanager

I have been dealing with an unusual set of errors when I try to compile my asp.net page. This page is inheriting from my masterpage. It should be getting the Scriptmanager from there. But the errors I am getting suggest that it is not.

Now I have this in my page:

    <%@ Page Title="MassUpdate" Language="C#"
         MasterPageFile="~/Site1.Master"
         AutoEventWireup="true"
         CodeBehind="Update.aspx.cs"
         Inherits="AdminSite.Update"
         MaintainScrollPositionOnPostback="true" %>


     <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server" >

        <div id="contentarea">
            <div>
                <h3 style="color:Red; padding-left:5px;">
                    WARNING - This page can push large amounts of data into the database. Use care when using it!
                </h3>
            </div>    


        <asp:ScriptManagerProxy runat="server"  >

        </asp:ScriptManagerProxy>

And in my masterpage, I have this:

<body>
    <header>
       <div id="banner">

            <h1 style="color:#DBFFFF">UAC Parts Admin</h1>    
    </div>
</header>
<form id="form1" runat="server">

<div id="container">

    <asp:ContentPlaceHolder ID="MainContent" runat="server">


    </asp:ContentPlaceHolder>
    <asp:LoginView ID="LoginView1" runat="server" EnableViewState="false">
        <LoggedInTemplate>
      <div id="menubar">

        <h6>Reports</h6>
        <div>
            <asp:ScriptManager ID="ScriptManager1" runat="server">
                <Scripts>
                    <asp:ScriptReference Path="~/Scripts/jquery.js" />
                    <asp:ScriptReference Path="~/Scripts/jqueryui.js" />
                    <asp:ScriptReference Path="~/Scripts/menubar.js" />
                </Scripts>
            </asp:ScriptManager>

The first error is this:

The control with ID '' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it.

It happens when I don't have ScriptManager on my page and use ScriptManagerProxy instead.Even though I have ScriptManager on my Master page.

Now when I put a ScriptManager on my page I get a different error.

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

What do I need to do to get this to work?
Is this an issue with one of my Nuget Packages? (JuiceUI,Widgmo, etc)

I would be glad to post code if requested.

EDIT:
Yeah, this whole thing has been weird. Oddly the master page did not have issues itself. But only when the other pages used it did I have any problems. Moving it to the first element after the form tag was the solution I believe. Though I had also moved the ScriptManagerProxy up a bit in my code too.

Best Answer

The ScriptManager must appear before any ContentPlaceHolders. Generally as Joshua pointed out, the script manager is put at the first element after the form tag. Like so:

<form id="form1" runat="server">

    <asp:ScriptManager ID="ScriptManager1" runat="server">
        <Scripts>
            <asp:ScriptReference Path="~/Scripts/jquery.js" />
            <asp:ScriptReference Path="~/Scripts/jqueryui.js" />
            <asp:ScriptReference Path="~/Scripts/menubar.js" />
        </Scripts>
    </asp:ScriptManager>

    <div id="container">

        <asp:ContentPlaceHolder ID="MainContent" runat="server">


        </asp:ContentPlaceHolder>
    </div>
</form>

The reason for this is because the .aspx pages that uses this master page provide content that is placed into the ContentPlaceHolder controls. Because your ContentPlaceHolder appeared before your ScriptManager, the ScriptManagerProxy located in your content page was throwing because the ScriptManager would not be defined until later down the page.

This can be a bit odd to think about because you are defining controls in multiple different places. But the codebehind does not execute until everything is put together.

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