Specifying the Parent Container

In this example we plan to use a DataGrid to display a list of all the objects in the selected container. However, before we can get the DataGrid to display a list of objects, we need to specify a parent container. The parent container will be a channel, resource gallery, or template gallery. We’ll need this container to determine the objects to be displayed in the DataGrid. If the user hasn’t specified a parent container, we use the root containers (i.e. the Channels channel, the Templates template gallery, and the Resources resource gallery).

Above and within the Page_Load() event handler, add the following code:

// the current CmsHttpContext
private CmsHttpContext cmsContext;

// the parent container whose contents we are displaying
					private HierarchyItem startItem;
private void Page_Load(object sender, System.EventArgs e)
{
  cmsContext = CmsHttpContext.Current;

  // Get the URL of the current page
					string currentUrl = HttpContext.Current.Request.Url.ToString();

  // Redirect if not in unpublished mode
  if (cmsContext.Mode != PublishingMode.Unpublished
       && cmsContext.Mode != PublishingMode.Update)
  {
    string query;
    query = cmsContext.RootChannel.QueryStringModeUnpublished;
    Response.Redirect(currentUrl + "?" + query);
  }

  InitializeStartItem();

  if (!Page.IsPostBack)
  {
    // Display the publishing mode
    lblPublishingMode.Text = "Publishing Mode: "
                  + cmsContext.Mode.ToString();

   // use the start channel's display name as the
					// header for the page
					litCurrentContainer.Text = startItem.Name;
  }
}

Add the InitializeStartItem() method directly below the Page_Load() event handler:

private void InitializeStartItem()
{
  // determine the object type
  string cmsObject = "";
  if (Request.QueryString["CMSObject"] != null)
  {
    cmsObject = Request.QueryString["CMSObject"].ToString();
  }

  // determine the GUID of the working container
  string cmsObjectGuid = "";
  if (Request.QueryString["CMSObjectGuid"] != null)
  {
    cmsObjectGuid = Request.QueryString["CMSObjectGuid"].ToString();
  }

  if (cmsObjectGuid == "")
  {
    // if not specified, we start with channels
    startItem = cmsContext.Channel;
  }
  else
  {
    startItem = cmsContext.Searches.GetByGuid(cmsObjectGuid);
  }

  // no working container has been specified. Use the root containers
  if (startItem == null)
  {
    switch(cmsObject)
    {
      case "Templates":
        // using the root template gallery
        startItem = cmsContext.RootTemplateGallery;
        break;
      case "Resources":
        // using the root resource gallery
        startItem = cmsContext.RootResourceGallery;
        break;
      default:
        // using the root channel
        startItem = cmsContext.RootChannel;
        break;
    }
  }
}

The code first determines the type of objects you are working with: channels, template galleries, or resource galleries. It gets this information from the CMSObject querystring parameter.

For channels, the logic is straightforward. Information about the channel is available from the CmsHttpContext.Channel property. If it isn’t null, the DataGrid uses that as the start channel. Otherwise, the root container is assigned to startItem.

For template galleries and resource galleries, the current gallery item can’t be obtained from the current CmsHttpContext. For these objects, the PAPI gets the GUID of the working container from the CMSObjectGuid querystring parameter we inserted earlier.