sharepoint 2019 solution添加自定義按鈕

問題描述：sharepoint2019有modern模式和經典模式兩種，16即以前版本只有經典模式，經典模式支持js腳本，modern下面寫了js腳本調用但是起不到作用

實現功能:在document library(RegistrationId='101')下面添加一個按鈕CustomButton1，按鈕實現alert("hello,Oliver!')功能

1.在原有16的solution（）下面element.xml的基礎上修改button的響應方法,將原來commandAction中"javascript:test();"改爲"="~site/_layouts/15/2019/BeforeCustomAction.aspx"

<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Control Id="PromotedActions"
 Sequence="91"
 ControlSrc="/_ControlTemplates/15/2019/BeforeCustomAction.ascx">
  </Control>
  <CustomAction
       Id="Ribbon.ListItem.Actions.Scripts"
       Location="ScriptLink"
       ScriptSrc ="/_layouts/15/2019/JS/CustomAction.js"/>
  <CustomAction Id="Ribbon.CustomGroup" RegistrationId="101" RegistrationType="List"
        Title="CustomButton1" Location="CommandUI.Ribbon">
    <CommandUIExtension>
      <CommandUIDefinitions>
        <CommandUIDefinition Location="Ribbon.Library.Settings.Controls._children">
          <Button Id="Ribbon.Library.New.CustomButton1"
          Command="AddFavourite"
          Image32by32="/_layouts/15/images/CustomButton1_32x32.png"
          LabelText="CustomButton1"
          Sequence="11"
          TemplateAlias="o1"
          ToolTipTitle="CustomButton1"                 
          ToolTipDescription="CustomButton1"/>
        </CommandUIDefinition>
      </CommandUIDefinitions>
      <CommandUIHandlers>
        <CommandUIHandler
        Command="AddFavourite"
        CommandAction="~site/_layouts/15/2019/BeforeCustomAction.aspx"/>
      </CommandUIHandlers>
    </CommandUIExtension>
  </CustomAction>
</Elements>

2.新創建一個BeforeCustomAction.aspx文件,在PageHead下面添加需要的腳本引用和方法調用，這樣就會在點擊OliverCustomButton1的時候調用js中test()方法

<asp:content id="PageHead" contentplaceholderid="PlaceHolderAdditionalPageHead" runat="server">
        <script type="text/javascript" src="JS/CustomAction.js"></script>   
    <script type="text/javascript">
        test();
    </script>    
</asp:content>

3.新建一個js腳本CustomAction.js,裏面加上函數方法

function test(){
    alert("Hello,Oliver!");
}

4.publish該project，然後在相應網站部署上solution,並且在CA上action feature,打開相應網站就可以看到新添加的button，並且點擊響應