Custom Filtering
Custom filtering is a flexible mechanism for filtering RadTreeView nodes by using custom logic. It has a higher priority than the applied FilterDescriptors.
In order to apply custom logic for filtering, you have to create a Predicate. Here is an example of a Predicate which will return just the nodes which text is longer than one char:
Creating predicate
private bool FilterNode(RadTreeNode node)
{
if (node.Text.Length > 1)
{
return true;
}
return false;
}
Private Function FilterNode(node As RadTreeNode) As Boolean
If node.Text.Length > 1 Then
Return True
End If
Return False
End Function
| Here you have nodes from 1-100 | After the filtering the nodes are only from 10-100, since nodes 1-9 contain just one char as text |
|---|---|
 |
 |
To set the Predicate to RadTreeView, use the FilterPredicate property of the control:
Applying predicate
radTreeView1.TreeViewElement.FilterPredicate = FilterNode;
RadTreeView1.TreeViewElement.FilterPredicate = AddressOf FilterNode
At the end, in order to apply the filter to the control, just set the Filter property to any string, which will invoke the filtering operation:
Invoke filtering
private void radButton1_Click(object sender, EventArgs e)
{
this.radTreeView1.Filter = "Custom";
}
Private Sub RadButton1_Click(sender As System.Object, e As System.EventArgs) Handles RadButton1.Click
Me.RadTreeView1.Filter = "Custom"
End Sub