通过代码将自定义链接添加到 SharePoint 列表设置页面

通过代码将自定义链接添加到 SharePoint 列表设置页面需要使用 SharePoint 的 REST API 和 CSOM（Client-side Object Model）。以下是一个完整的解决方案：

使用 REST API 创建自定义操作

首先，我们需要创建一个自定义操作，这将在列表设置页面上显示为一个链接。我们可以使用 REST API 来创建这个操作。以下是一个示例代码：

function createCustomAction() {
  var requestUri = _spPageContextInfo.webAbsoluteUrl + "/_api/web/usercustomactions";
  var requestHeaders = {
    "accept": "application/json;odata=verbose",
    "content-type": "application/json;odata=verbose",
    "X-RequestDigest": $("#__REQUESTDIGEST").val()
  };
  var requestData = {
    "__metadata": { "type": "SP.UserCustomAction" },
    "Title": "My Custom Link",
    "Description": "This is a custom link that will be added to the SharePoint list settings page.",
    "Location": "Microsoft.SharePoint.StandardMenu",
    "Group": "SiteActions",
    "Sequence": 1000,
    "Url": "https://www.example.com"
  };
  return $.ajax({
    url: requestUri,
    type: "POST",
    headers: requestHeaders,
    data: JSON.stringify(requestData)
  });
}

使用 CSOM 将自定义操作添加到列表设置页面

接下来，我们需要使用 CSOM 将自定义操作添加到列表设置页面。以下是一个示例代码：

using (var clientContext = new ClientContext("https://your-tenant.sharepoint.com/sites/your-site"))
{
    var web = clientContext.Web;
    var list = web.Lists.GetByTitle("Your List");
    var customAction = list.UserCustomActions.Add();
    customAction.Title = "My Custom Link";
    customAction.Description = "This is a custom link that will be added to the SharePoint list settings page.";
    customAction.Location = "Microsoft.SharePoint.StandardMenu";
    customAction.Group = "SiteActions";
    customAction.Sequence = 1000;
    customAction.Url = "https://www.example.com";
    customAction.Update();
    clientContext.ExecuteQuery();
}

将自定义操作添加到列表设置页面

最后，我们需要将自定义操作添加到列表设置页面。以下是一个示例代码：

function addCustomActionToSettingsPage() {
  var settingsPageUrl = _spPageContextInfo.webAbsoluteUrl + "/_layouts/15/listedit.aspx?List=" + _spPageContextInfo.pageListId;
  var requestUri = settingsPageUrl + "?loadCustomActions=true";
  var requestHeaders = {
    "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9",
    "X-RequestDigest": $("#__REQUESTDIGEST").val()
  };
  return $.ajax({
    url: requestUri,
    type: "GET",
    headers: requestHeaders
  }).done(function(response) {
    var customActionLink = "<a href='https://www.example.com' target='_blank'>My Custom Link</a>";
    var $settingsPage = $(response);
    $settingsPage.find("#DeltaPlaceHolderPageTitleInTitleArea").append(customActionLink);
    $settingsPage.find("#DeltaPlaceHolderPageTitleInTitleArea").css("display", "inline-block");
    $settingsPage.find("#DeltaPlaceHolderPageTitleInTitleArea").css("float", "left");
    $settingsPage.find("#DeltaPlaceHolderPageTitleInTitleArea").css("margin-right", "10px");
    $("body").html($settingsPage);
  });
}

这个解决方案将创建一个自定义操作，并将其添加到列表设置页面上。当用户点击该链接时，将会打开一个新的标签页，链接到指定的 URL。