Hi Yordon,
We have checked your query on performance problem in TreeView component. When you expanded all the TreeView nodes, then it will load the 1000 nodes in the approximate of 5 seconds. By default, TreeView component has a lazy loading functionality. By default, TreeView component has LoadOnDemand (Lazy loading).
LoadOnDemand reduces the bandwidth size when consuming huge data. It loads first level nodes initially, and when parent node is expanded, loads the child nodes based on the ParentID/Child
member. By default, the LoadOnDemand
is set to true.
When you set the loadOnDemand as true and expanded property as false, when initializing TreeView. The parent nodes will be accessed from the server-side and it will gets generated into the DOM. Only when expanding any tree node, its child node will be accessed from the server side and loaded in DOM. By using this functionalities, you can reduce the performance of TreeView component.
Refer the below link to know more about the loadOnDemand of TreeView component.
Please let us know, if you need any further assistance.
Regards,
Sowmiya.P