PnP PowerShell将很多内容隐藏起来，以使你轻松使用。

要将代码修改为C＃，需要按如下所述编写：

var siteUrl = "https://your-sitecollection-url";
var userName = "userName";
var password = "password";

using (ClientContext clientContext = new ClientContext(siteUrl))
{
    SecureString securePassword = new SecureString();
    foreach (char c in password.ToCharArray())
    {
        securePassword.AppendChar(c);
    }

    clientContext.AuthenticationMode = ClientAuthenticationMode.Default;
    clientContext.Credentials = new SharePointOnlineCredentials(userName, securePassword);

    clientContext.ExecuteQuery();

    var ServerVersion = clientContext.ServerLibraryVersion.Major;

    var site = clientContext.Site;
    var web = clientContext.Site.RootWeb;

    clientContext.Load(web, w => w.ServerRelativeUrl);
    clientContext.ExecuteQuery();

    var serverRelativeUrl = clientContext.Site.RootWeb.ServerRelativeUrl;
}

要执行此代码，你的项目中将需要Microsoft.SharePointOnline.CSOM nuget包。