From 96ee366063c090274cf3d6e1b2d50780eeaaadec Mon Sep 17 00:00:00 2001
From: dmlvr <lvr@dmlvr.com>
Date: Wed, 21 Jan 2026 15:41:57 +0200
Subject: [PATCH 1/2] add allowSelect option and functions

---
 .../__internal/ui/tree_view/tree_view.base.ts | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/packages/devextreme/js/__internal/ui/tree_view/tree_view.base.ts b/packages/devextreme/js/__internal/ui/tree_view/tree_view.base.ts
index fd4680d6cbfd..4870c31209ad 100644
--- a/packages/devextreme/js/__internal/ui/tree_view/tree_view.base.ts
+++ b/packages/devextreme/js/__internal/ui/tree_view/tree_view.base.ts
@@ -96,6 +96,8 @@ export interface TreeViewBaseProperties extends Properties<TreeViewNode>, Omit<
 > {
   deferRendering?: boolean;
 
+  allowSelect?: boolean | ((e: { component: TreeViewBase; item: ItemData }) => boolean);
+
   _supportItemUrl?: boolean;
 }
 
@@ -256,6 +258,7 @@ class TreeViewBase extends HierarchicalCollectionWidget<TreeViewBaseProperties,
   _getDefaultOptions(): TreeViewBaseProperties {
     const defaultOptions = {
       ...super._getDefaultOptions(),
+      allowSelect: true,
       animationEnabled: true,
       dataStructure: 'tree',
       deferRendering: true,
@@ -1549,6 +1552,10 @@ class TreeViewBase extends HierarchicalCollectionWidget<TreeViewBaseProperties,
   }
 
   _renderCheckBox($node: dxElementWrapper, node: TreeViewNode | null): void {
+    if (!this._isItemSelectable(node)) {
+      return;
+    }
+
     const $checkbox = $('<div>').appendTo($node);
 
     this._createComponent<CheckBox, CheckBoxProperties>($checkbox, CheckBox, {
@@ -1581,6 +1588,28 @@ class TreeViewBase extends HierarchicalCollectionWidget<TreeViewBaseProperties,
     }
   }
 
+  _isItemSelectable(node: TreeViewNode | null): boolean {
+    if (!node) {
+      return true;
+    }
+
+    const { allowSelect } = this.option();
+
+    if (typeof allowSelect === 'boolean') {
+      return allowSelect;
+    }
+
+    if (isFunction(allowSelect)) {
+      const result = allowSelect({
+        component: this,
+        item: node.internalFields.item,
+      });
+      return Boolean(result);
+    }
+
+    return true;
+  }
+
   _itemOptionChanged(item: Item, property: keyof Item, value: unknown): void {
     const node = this._dataAdapter.getNodeByItem(item);
     const { disabledExpr } = this.option();
@@ -1670,6 +1699,10 @@ class TreeViewBase extends HierarchicalCollectionWidget<TreeViewBaseProperties,
       return false;
     }
 
+    if (!this._isItemSelectable(node)) {
+      return false;
+    }
+
     if (node.internalFields.selected === value) {
       return true;
     }

From a4a6a30fb27cbb1b168c61c8cca3d6c9357132b0 Mon Sep 17 00:00:00 2001
From: dmlvr <lvr@dmlvr.com>
Date: Wed, 21 Jan 2026 17:54:12 +0200
Subject: [PATCH 2/2] update getSelectedNodes

---
 .../devextreme/js/__internal/ui/tree_view/tree_view.base.ts  | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/devextreme/js/__internal/ui/tree_view/tree_view.base.ts b/packages/devextreme/js/__internal/ui/tree_view/tree_view.base.ts
index 4870c31209ad..f565b01181f0 100644
--- a/packages/devextreme/js/__internal/ui/tree_view/tree_view.base.ts
+++ b/packages/devextreme/js/__internal/ui/tree_view/tree_view.base.ts
@@ -2244,7 +2244,10 @@ class TreeViewBase extends HierarchicalCollectionWidget<TreeViewBaseProperties,
   }
 
   getSelectedNodeKeys(): ItemKey[] {
-    return this._dataAdapter.getSelectedNodesKeys();
+    return this._dataAdapter.getSelectedNodesKeys().filter((key: ItemKey) => {
+      const node = this._dataAdapter.getNodeByKey(key) as TreeViewNode;
+      return this._isItemSelectable(node);
+    });
   }
 
   selectAll(): void {