Nguyễn Hữu HiếuProblem
- Each time angular material tree refresh or update data source => tree auto collapse all row
Solution
- Save tree expanded state before update data
expandedNodeSet = new Set<any>();
private saveExpandedNode(): void {
const mExpandedNode =
this.treeControl?.dataNodes
?.filter((node) => {
return this.treeControl.isExpanded(node);
})
.map((node) => node.id) || [];
this.expandedNodeSet = new Set(mExpandedNode);
}
private restoreExpandedNode(): void {
this.treeControl.dataNodes.forEach((node) => {
const id = node.id;
const result = this.expandedNodeSet.has(id);
if (result) {
this.treeControl.expand(node);
}
});
}
