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Rank: Advanced Member
Groups: Member
Joined: 4/30/2009
Posts: 36
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I have a Treeview which saves state across pages when NOT in a masterpage. However, when embedded in a masterpage, it does not save state. Do I need to save state in session and then restore it from the session after postback?
Thanks
Kennaxx
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Rank: Administration
Groups: Administration
Joined: 5/27/2007
Posts: 24,194
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Hi,
No. The TreeView should not have a problem with master page in general, so it's more likely has to do with your particular scenario. The most likely problem is the ClientID changes across different pages. The TreeView must have exactly same ID in all pages.
Also I do not think save state cross page works when the TreeView raises server event. It only works when the TreeView navigate to another page through NavigateUrl.
If the problem continues, please create a test project to reproduce the problem. Once we have that we will debug it here and see what we can find.
Thanks!
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Rank: Advanced Member
Groups: Member
Joined: 4/30/2009
Posts: 36
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EO,
This is the code that I have to save/restore the Treeview before/after posts. The node.Childnodes.count keeps coming out count of 0 eventhough I am 100% sure it should not be 0.
public class EOTreeViewState
{
public void SaveTreeView(EO.Web.TreeView treeView, string key)
{
List<bool?> list = new List<bool?>();
SaveTreeViewExpandedState(treeView.Nodes, list);
HttpContext.Current.Session[key + treeView.ID] = list;
}
private void SaveTreeViewExpandedState(EO.Web.TreeNodeCollection nodes, List<bool?> list)
{
foreach (EO.Web.TreeNode node in nodes)
{
list.Add(node.Expanded);
if (node.ChildNodes.Count > 0)
{
SaveTreeViewExpandedState(node.ChildNodes, list);
}
}
}
private int RestoreTreeViewIndex;
public void RestoreTreeView(EO.Web.TreeView treeView, string key)
{
RestoreTreeViewIndex = 0;
RestoreTreeViewExpandedState(treeView.Nodes,
(List<bool?>)HttpContext.Current.Session[key + treeView.ID] ?? new List<bool?>());
}
private void RestoreTreeViewExpandedState(EO.Web.TreeNodeCollection nodes, List<bool?> list)
{
foreach (EO.Web.TreeNode node in nodes)
{
if (RestoreTreeViewIndex >= list.Count) return;
node.Expanded = (bool)list[RestoreTreeViewIndex++];
if (node.ChildNodes.Count > 0)
{
RestoreTreeViewExpandedState(node.ChildNodes, list);
}
}
}
}
Thanks Kennaxx
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Rank: Administration
Groups: Administration
Joined: 5/27/2007
Posts: 24,194
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Hi,
I am not quite clear about what you wanted to save. Your function saves/restores node state, but not the node themselves.
TreeView automatically saves/restores all nodes and state for nodes state through view state. When you navigate from one page to another, view state is discarded. So in this case it does not restore nodes that you have dynamically created. For example, if you have a blank TreeView in your master page, and Button1 and Button2 in Page1 (Page1 ueses master page) and:
1. Button1 adds a new TreeNode into the TreeView. So after Button1 is clicked, TreeView has one node;
2. Button2 redirects to Page2 (which also use the same master page). Once the page is redirected to Page2, TreeView will be blank again;
This is normal. If you wish the TreeView to retain all nodes created in Page1, you will need to save it somehow. For example, you can save it in the Session or in the database.
Thanks!
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