Understanding TreeView Control
TreeView Control is used for showing hierarchical structured data visually eg. XML.
Class Hierarchy of TreeView Control
- TreeView
- TreeNodeCollection
- TreeNode
TreeView is contains collection of TreeNodes. Each TreeNode is a member of TreeNodeCollection.
TreeNode is a type of recursive Data Structure as itself contains Collection of TreeNodes. All TreeNodes are number from 0 to Nodes.Count-1 sequentially in the order of appearance irrespective of the hierarchical structure
Sample:
ROOT
T1
T11
T2
For the above structure the nodes are numbered as
ROOT - 1
T1 - 2
T11 - 3
T2 - 4
1. Creating TreeView
TreeView is created by instancing the TreeView class.
Sample:
TreeView tvSample = new TreeView();
2. Add Nodes to TreeView
The Nodes property of the TreeView is an instance of TreeNodeCollection class which is used to Add/Remove Nodes.
Sample:
tvSample.Nodes.Add("Sample")
or
tvSample.Nodes.Add(new TreeNode("Sample"))
3. Removing Nodes from TreeView
The Nodes Property of the TreeView is an instance of TreeNodeCollection class which is used to Add/Remove Nodes.
Sample:
tvSample.Nodes.RemoveAt(1) //To Remove the First appearing node in the Tree.
or
tvSample.Nodes.Remove(tvSample.SelectedNode) //Removes the currently selected node.
4. Determine the SelectedNode
SelectedNode property is used to determine the currently selected node in the Tree.
Sample:
string nodeText=tvSample.SelectedNode.Text;
will retrieve the Text of the selected node.
Other Useful Members of TreeView
TreeView::Indent
Space between Parent and child nodes.
TreeView::ItemHeight
Height of each TreeNode in the Tree.
TreeNode::FullPath
Returns the Path of the Node from the its Topmost Parent.
Sample:
ROOT
T1
T11
T2
Fullpath of T2 is ROOT/T1/T11/T2
TreeNode::Expand()
Expand the currently selected node.
TreeNode::ExpandAll()
Expand the currently selected node and all its child hierarchy.
TreeNode::Collapse()
Collapse the currently selected node.
TreeNode::ImageIndex
Showing an image in TreeNode.To use this property.The TreeView's ImageList
property is set to an ImageList.
Useful Tips
[Q] How do I show all the Nodes in the TreeView?
[A] tvSample.SelectedNode=tvSample.Nodes[0]
tvSample.SelectedNode.ExpandAll()
[Q] How do I collapse all the parent Nodes in the TreeView?
[A] It's not possible directly but can be done using coding.
void CollapseTree(TreeNode ParentNode)
{
if(ParentNode.IsExpanded)
ParentNode.Toggle();
for(int i=ParentNode.Nodes.Count-1;i>=0;i--)
{
if(ParentNode.Nodes[i].Nodes.Count>0)
{
if(ParentNode.Nodes[i].IsExpanded)
ParentNode.Nodes[i].Toggle();
CollapseTree(ParentNode.Nodes[i])
}
}
}
[Q] How do I make the NodeText as Hyperlink?
[A] tvSample.HotTracking=true;
[Q] Can I have Checkboxes in TreeNode?
[A]tvSample.CheckBoxes=true;
[Q] How do I show all the Nodes in the TreeView?
[A] tvSample.SelectedNode=tvSample.Nodes[0]
tvSample.SelectedNode.ExpandAll()
[Q] How do I collapse all the parent Nodes in the TreeView?
[A] It's not possible directly but can be done using coding.
void CollapseTree(TreeNode ParentNode)
{
if(ParentNode.IsExpanded)
ParentNode.Toggle();
for(int i=ParentNode.Nodes.Count-1;i>=0;i--)
{
if(ParentNode.Nodes[i].Nodes.Count>0)
{
if(ParentNode.Nodes[i].IsExpanded)
ParentNode.Nodes[i].Toggle();
CollapseTree(ParentNode.Nodes[i])
}
}
}
[Q] How do I make the NodeText as Hyperlink?
[A] tvSample.HotTracking=true;
[Q] Can I have Checkboxes in TreeNode?
[A]tvSample.CheckBoxes=true;
Munesh SharmaPosted May 25, 2016, 12:38 AM
nice
Pradeep KumarPosted May 23, 2010, 3:23 PM
http://pradeep1210.spaces.live.com/Blog/cns!2E84C99518D46BB4!258.entry
hamid hematiPosted Apr 7, 2010, 3:40 AM
esfw
Gokhan GuvenPosted Nov 12, 2009, 7:02 PM
Hi thanks for the post. I want to learn that how can i show count of all nodes of treeview ? for example i will click buton and it will show at label the count of all nodes of treview.
Tedd SandstromPosted Sep 8, 2008, 10:46 AM
needs forms in download to complete the example