Tree TreeItemRender event added

Radzen.Blazor/Common.cs

@@ -2639,6 +2639,51 @@ public class TreeItemSettings
         public RenderFragment<RadzenTreeItem> Template { get; set; }
     }
 
+    /// <summary>
+    /// Supplies information about a <see cref="RadzenTree" /> item render event that is being raised.
+    /// </summary>
+    public class TreeItemRenderEventArgs
+    {
+        /// <summary>
+        /// Gets or sets the item HTML attributes. 
+        /// </summary>
+        public IDictionary<string, object> Attributes { get; private set; } = new Dictionary<string, object>();
+
+        bool _checkedSet;
+        internal bool CheckedSet()
+        {
+            return _checkedSet;
+        }
+
+        bool? _checked;
+        /// <summary>
+        /// Gets or sets a value indicating whether this item is checked.
+        /// </summary>
+        /// <value><c>true</c> if expanded; otherwise, <c>false</c>.</value>
+        public bool? Checked 
+        {
+            get
+            {
+                return _checked;
+            }
+            set
+            {
+                _checkedSet = true;
+                _checked = value;
+            }
+        }
+
+        /// <summary>
+        /// Gets tree item.
+        /// </summary>
+        public object Value { get; internal set; }
+
+        /// <summary>
+        /// Gets child items.
+        /// </summary>
+        public IEnumerable Data { get; internal set; }
+    }
+
     /// <summary>
     /// Supplies information about a <see cref="RadzenLogin.Login" /> event that is being raised.
     /// </summary>

Radzen.Blazor/RadzenTree.razor.cs

@@ -114,6 +114,24 @@ protected override string GetComponentCssClass()
         [Parameter]
         public EventCallback<TreeEventArgs> Collapse { get; set; }
 
+        /// <summary>
+        /// A callback that will be invoked when item is rendered.
+        /// </summary>
+        [Parameter]
+        public Action<TreeItemRenderEventArgs> ItemRender { get; set; }
+
+        internal Tuple<Radzen.TreeItemRenderEventArgs, IReadOnlyDictionary<string, object>> ItemAttributes(RadzenTreeItem item)
+        {
+            var args = new TreeItemRenderEventArgs() { Data = item.GetAllChildValues(), Value = item.Value };
+
+            if (ItemRender != null)
+            {
+                ItemRender(args);
+            }
+
+            return new Tuple<TreeItemRenderEventArgs, IReadOnlyDictionary<string, object>>(args, new System.Collections.ObjectModel.ReadOnlyDictionary<string, object>(args.Attributes));
+        }
+
         /// <summary>
         /// Gets or sets the child content.
         /// </summary>

Radzen.Blazor/RadzenTreeItem.razor

@@ -1,15 +1,16 @@
 @using Radzen
 @using Radzen.Blazor.Rendering
 @implements IDisposable
-<li class="rz-treenode" @attributes="Attributes">
+@{var itemArgs = Tree?.ItemAttributes(this); }
+<li class="rz-treenode" @attributes="@(itemArgs.Item1.Attributes.Any() ? itemArgs.Item1.Attributes : Attributes)">
     <div class=@ContentClassList @onclick="@Select">
         @if (ChildContent != null || HasChildren)
         {
             <span class=@IconClassList @onclick="@Toggle" @onclick:stopPropagation></span>
         }
         @if(Tree != null && Tree.AllowCheckBoxes)
         {
-            <RadzenCheckBox TabIndex=-1 Name="@($"{GetHashCode()}")" TValue="bool?" Value="@IsChecked()" Change="@CheckedChange" InputAttributes="@(new Dictionary<string,object>(){ { "aria-label", Tree.SelectItemAriaLabel }})" />
+            <RadzenCheckBox TabIndex=-1 Name="@($"{GetHashCode()}")" TValue="bool?" Value="@(itemArgs.Item1.CheckedSet() ? itemArgs.Item1.Checked : IsChecked())" Change="@CheckedChange" InputAttributes="@(new Dictionary<string,object>(){ { "aria-label", Tree.SelectItemAriaLabel }})" />
         }
         @if (Template != null)
         {

Radzen.Blazor/RadzenTreeItem.razor.cs

@@ -361,7 +361,7 @@ IEnumerable<object> GetCheckedValues()
             return Tree.CheckedValues != null ? Tree.CheckedValues : Enumerable.Empty<object>();
         }
 
-        IEnumerable<object> GetAllChildValues(Func<object, bool> predicate = null)
+        internal IEnumerable<object> GetAllChildValues(Func<object, bool> predicate = null)
         {
             var children = items.Concat(items.SelectManyRecursive(i => i.items)).Select(i => i.Value);
 

RadzenBlazorDemos/Pages/TreeCheckBoxes.razor

@@ -7,7 +7,8 @@
     <div class="row my-5">
         <div class="col-lg-6 offset-lg-3">
             <RadzenCard>
-                <RadzenTree AllowCheckBoxes="true" @bind-CheckedValues=@CheckedValues Style="width: 100%; height: 300px" Data=@categories>
+                <RadzenTree AllowCheckBoxes="true" @bind-CheckedValues=@CheckedValues Style="width: 100%; height: 300px" Data=@categories
+                    ItemRender="@TreeItemRender">
                     <RadzenTreeLevel TextProperty="CategoryName" ChildrenProperty="Products" />
                     <RadzenTreeLevel TextProperty="ProductName" HasChildren=@(product => false) />
                 </RadzenTree>
@@ -57,5 +58,15 @@
         await base.OnInitializedAsync();
 
         categories = dbContext.Categories.Include(c => c.Products);
+
+        checkedValues = dbContext.Products.Where(p => p.ProductName.StartsWith("C"));
+    }
+
+    void TreeItemRender(TreeItemRenderEventArgs args)
+    {
+        if (args.Value == categories.FirstOrDefault() && !args.Data.Cast<object>().Any())
+        {
+            args.Checked = null;
+        }
     }
 }