TreeView - Collapse All Nodes Except SelectedNode's Parent Nodes

Question

User322428247 posted

Control Markup

<asp:TreeView ID="tv_Menu" 
         DataSourceId="nav1"  
         OnDataBound="tv_Menu_DataBound"  
         runat="server" />

Code Behind

Add more cases for a deeper tree.

protected void tv_Menu_DataBound(object sender, EventArgs e) {
tv_Menu.CollapseAll();
if (tv_Menu.SelectedNode != null) {
	TreeNode tn = tv_Menu.SelectedNode;
	switch (tn.Depth) {
		case 5:
		tn.Parent.Parent.Parent.Parent.Parent.Expand();
		tn.Parent.Parent.Parent.Parent.Expand();
		tn.Parent.Parent.Parent.Expand();
		tn.Parent.Parent.Expand();
		tn.Parent.Expand();
		break;

		case 4:
		tn.Parent.Parent.Parent.Parent.Expand();
		tn.Parent.Parent.Parent.Expand();
		tn.Parent.Parent.Expand();
		tn.Parent.Expand();
		break;

		case 3:
		tn.Parent.Parent.Parent.Expand();
		tn.Parent.Parent.Expand();
		tn.Parent.Expand();
		break;

		case 2:
		tn.Parent.Parent.Expand();
		tn.Parent.Expand();
		break;

		case 1:
		tn.Parent.Expand();
		break;
	}
}
}

Answer 1

User1224194097 posted

You have to use SelectedNodeChanged Event. SelectedNode will be null in databound event.

protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
{
    //Expand Nodes here
}

Answer 2

User-371711912 posted

This is an awful way to write it, and will probably end up on thedailywtf.com.

You should recursively step though the selected node and its parents to expand them.

Answer 3

User322428247 posted

Selected node is not null, the code works.

Have a better solution key? post some code.

Answer 4

User-205780277 posted

Try something like this:

 

// First Collpase All Nodes
tv_Menu.CollapseAll();

// Then expand the SelectedNode and ALL its parents until no parent found
TreeNode tn = tv_Menu.SelectedNode;
tn.Expand();
while (tn.Parent != null)
{
     tn = tn.Parent;
     tn.Expand();
}

Answer 5

User-47646173 posted

hi ,

in cs file its ok

but how this code will be use . any link with aspx file

please answer

thanks