Filter CategoriesTree control by Blog.

December 09, 2009 Digital Experience

The main reason of this post is a discussion that I had in Sitefinity's forum post. So, the problem here is that you have BlogPosts control that supports filtering, but the same does not apply for CategoriesTree control. Using BlogPosts FilterExpression property you can  show only a specific blog posts or group of blog posts instead of all blogs and posts from your provider. So far so good. The main problem comes here. When you drop CategoriesTree built-in control on a page and set ProviderName property, the CategoriesTree control is bound to all categories for this provider instead of categories related to your filtered list of blogs only. I managed to come up with a simple solution that requires creating a custom control that derives from CategoriesTree, implementing a simple property and overriding one method - BindCategories.

1. The property - I will implement a simple property of type Guid[] which will be used to return the ID of selected blogs. These blogs should be the same as those one listed in BlogPosts control

 

 [Category("FilterByCategories")] 
    [TypeConverter("Telerik.Blogs.WebControls.SelectedBlogsConverter, Telerik.Blogs")] 
    [WebEditor("Telerik.Blogs.WebControls.BlogsSelector, Telerik.Blogs")] 
    public Guid[] SelectedBlogs 
    { 
        get
        { 
            returnthis.selectedBlogs; 
        } 
        set
        { 
            this.selectedBlogs = value; 
        } 
    } 

2. Override LayoutTemplatePath property - we will "map" the external template for CategoriesTree which will allow to make some modifications in RadTreeView declaration.

   publicoverridestring LayoutTemplatePath 
    { 
        get
        { 
            return"~/Sitefinity/ControlTemplates/Generic_Content/CategoriesTree.ascx"
        } 
    } 
 

3. Override BindCategories() method.

- here I check whether there is a value set for our property SelectedBlog.  If there is no value I call the base and do not change anything. If there is a value set, I proceed with our custom logic.

- Get the blogs by IDs.

- Get all posts from our blogs

- get metadata - Category for IContent object

- create a new generic list of type ICategory

- add all matches to this list

- bind RadTreeView control to our custom list

- subscribe for NodeDataBound of RadTreeView control to set the node.NavigateUrl property.

 

The full code is shown below:

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using Telerik.Cms.Engine.WebControls.Categories; 
using Telerik.Cms.Web.UI; 
using System.ComponentModel; 
using System.Collections; 
using Telerik.Cms.Engine; 
using Telerik.Blogs; 
using Telerik.Cms; 
 
/// <summary>
/// Summary description for CategoriesTreeFiltered
/// </summary>
publicclass CategoriesTreeFiltered :CategoriesTree 
    public CategoriesTreeFiltered() 
    { 
    } 
#region properties
    publicoverridestring LayoutTemplatePath 
    { 
        get
        { 
            return"~/Sitefinity/ControlTemplates/Generic_Content/CategoriesTree.ascx"
        } 
    } 
 
    [Category("FilterByCategories")] 
    [TypeConverter("Telerik.Blogs.WebControls.SelectedBlogsConverter, Telerik.Blogs")] 
    [WebEditor("Telerik.Blogs.WebControls.BlogsSelector, Telerik.Blogs")] 
    public Guid[] SelectedBlogs 
    { 
        get
        { 
            returnthis.selectedBlogs; 
        } 
        set
        { 
            this.selectedBlogs = value; 
        } 
    } 
    
#endregion
    #region Methods
 
    protectedoverridevoid BindCategories() 
    { 
        IList categories; 
 
        blogManager = new BlogManager("Blogs"); 
        if (this.selectedBlogs.Length == 0) 
            // call the base class we will not change anything.
            base.BindCategories(); 
        else
        { 
            IList allCategories = new List<ICategory>(); 
            if (string.IsNullOrEmpty(RootCategory)) 
            { 
                allCategories = blogManager.Content.GetCategories(0, 0, "CategoryName ASC"); 
            } 
            else
            { 
                ICategory rootCategory = blogManager.Content.GetCategory(RootCategory); 
                allCategories = blogManager.Content.GetCategoriesTree(rootCategory); 
            } 
            IList allselectedBlogs = blogManager.GetBlogs(selectedBlogs); 
            IList<ICategory> filteredList = new List<ICategory>(); 
            foreach (IBlog blog in allselectedBlogs) 
            { 
                if (blog.PostsCount > 0) 
                { 
                    IList blogposts = blog.Posts; 
                    foreach (IContent cnt in blogposts) 
                    { 
                        string postCategory = (string)cnt.GetMetaData("Category"); 
                        if (!string.IsNullOrEmpty(postCategory)) 
                        { 
                            ICategory cat = Manager.GetCategory(postCategory); 
                            if (!filteredList.Contains(cat) && allCategories.Contains(cat)) 
                            { 
                                filteredList.Add(cat); 
                            } 
                            var parentId = cat.ParentCategoryID; 
                            while (parentId != Guid.Empty) 
                            { 
                                ICategory cat1 = Manager.GetCategory(parentId); 
                                if (!filteredList.Contains(cat1)) 
                                    filteredList.Add(cat1); 
                                parentId = cat1.ParentCategoryID; 
                            } 
                        } 
                    } 
                } 
            } 
             
          
        this.CategoriesTreeView.DataTextField = "CategoryName"
        this.CategoriesTreeView.DataFieldID = "ID"
        this.CategoriesTreeView.DataValueField = "ID"
        this.CategoriesTreeView.DataFieldParentID = "ParentCategoryID"
        this.CategoriesTreeView.DataSource = filteredList; 
        this.CategoriesTreeView.NodeDataBound +=new Telerik.Web.UI.RadTreeViewEventHandler(CategoriesTreeView_NodeDataBound); 
        this.CategoriesTreeView.DataBind(); 
 
        } 
 
    } 
    // you can unsubscribe from the event if you do not want to use ToolTip
    void CategoriesTreeView_NodeDataBound(object sender, Telerik.Web.UI.RadTreeNodeEventArgs e) 
    { 
        ICategory nodeCategory = (ICategory)e.Node.DataItem; 
        e.Node.NavigateUrl = base.GetNodeUrl(nodeCategory.CategoryName, nodeCategory.ID.ToString()); 
        e.Node.ToolTip = nodeCategory.CategoryName; 
        
    } 
    #endregion
    #region Private contstraints
    private Guid[] selectedBlogs = new Guid[] {}; 
    private BlogManager blogManager; 
    #endregion
 
  

 

 

The Progress Team