CODEWITHSUNDEEP
asp.nettreeview
BlackMael
BlackMael

Reputation: 3208

ASP.NET TreeView and Selecting the Selected Node

How do I capture the event of the clicking the Selected Node of a TreeView? It doesn't fire the SelectedNodeChanged since the selection has obviously not changed but then what event can I catch so I know that the Selected Node was clicked?

UPDATE: When I have some time, I'm going to have to dive into the bowels of the TreeView control and dig out what and where it handles the click events and subclass the TreeView to expose a new event OnSelectedNodeClicked.

I'll probably do this over the Christmas holidays and I'll report back with the results.

UPDATE: I have come up with a solution below that sub-classes the TreeView control.

Upvotes: 14

Views: 99887

Answers (9)

French Refilou
French Refilou

Reputation: 1

I use the ShowCheckBox property and the Checked property to "highlight" the selected item. When the SelectedNodeChanged event raises:

  1. I set to false the ShowCheckBox property and the Checked property for the old selected one and I set to true the ShowCheckBox property and the Checked property for the new selected one.
  2. I use the selected node for any action
  3. Finally, I unselect the selected item: myTreeView.SelecteNode.Selected = false

Upvotes: 0

Evren
Evren

Reputation: 19

protected void Page_Load(object sender, EventArgs e) 
    {
        if (!IsPostBack)
        {
            TreeView1.SelectedNode.Selected = false;
        }
    }

works for me

Upvotes: 1

MOJTABA GIVI
MOJTABA GIVI

Reputation: 1

i have a problem look like but i solved it !

in server side code :

    protected void MainTreeView_SelectedNodeChanged(object sender, EventArgs e)
    {
        ClearTreeView();
        MainTreeView.SelectedNode.Text = "<span class='SelectedTreeNodeStyle'>" + MainTreeView.SelectedNode.Text + "</span>";
        MainTreeView.SelectedNode.Selected = false;

    }

    public void ClearTreeView()
    {
         for (int i = 0; i < MainTreeView.Nodes.Count; i++)
        {
            for(int j=0;j< MainTreeView.Nodes[i].ChildNodes.Count;j++)
            {
                ClearNodeText(MainTreeView.Nodes[i].ChildNodes[j]);
            }
            ClearNodeText(MainTreeView.Nodes[i]);
        }
    }

    public void ClearNodeText(TreeNode tn)
    {
        tn.Text = tn.Text.Replace("<span class='SelectedTreeNodeStyle'>", "").Replace("</span>", "");
    }

in client side code :

 <style type="text/css">
     .SelectedTreeNodeStyle { font-weight: bold;}
 </style>

Upvotes: -1

Randa Hesham
Randa Hesham

Reputation: 13

c#:

TreeNode node = TreeTypes.FindNode(obj.CustomerTypeId.ToString());


TreeTypes.Nodes[TreeTypes.Nodes.IndexOf(node)].Select();

Upvotes: 1

BlackMael
BlackMael

Reputation: 3208

After a somewhat lengthy period, I have finally had some time to look into how to subclass the TreeView to handle a Selected Node being clicked.

Here is my solution which exposes a new event SelectedNodeClicked which you can handle from the Page or wherever. (If needed it is a simple task to refactor into C#)

Imports System.Web.UI
Imports System.Web


Public Class MyTreeView
  Inherits System.Web.UI.WebControls.TreeView

  Public Event SelectedNodeClicked As EventHandler

  Private Shared ReadOnly SelectedNodeClickEvent As Object

  Private Const CurrentValuePathState As String = "CurrentValuePath"

  Protected Property CurrentValuePath() As String
    Get
      Return Me.ViewState(CurrentValuePathState)
    End Get
    Set(ByVal value As String)
      Me.ViewState(CurrentValuePathState) = value
    End Set
  End Property

  Friend Sub RaiseSelectedNodeClicked()

    Me.OnSelectedNodeClicked(EventArgs.Empty)

  End Sub

  Protected Overridable Sub OnSelectedNodeClicked(ByVal e As EventArgs)

    RaiseEvent SelectedNodeClicked(Me, e)

  End Sub

  Protected Overrides Sub OnSelectedNodeChanged(ByVal e As System.EventArgs)

    MyBase.OnSelectedNodeChanged(e)

    ' Whenever the Selected Node changed, remember its ValuePath for future reference
    Me.CurrentValuePath = Me.SelectedNode.ValuePath

  End Sub

  Protected Overrides Sub RaisePostBackEvent(ByVal eventArgument As String)

    ' Check if the node that caused the event is the same as the previously selected node
    If Me.SelectedNode IsNot Nothing AndAlso Me.SelectedNode.ValuePath.Equals(Me.CurrentValuePath) Then
      Me.RaiseSelectedNodeClicked()
    End If

    MyBase.RaisePostBackEvent(eventArgument)

  End Sub

End Class

Upvotes: 6

Drell
Drell

Reputation: 166

When you're adding nodes to the tree in the _TreeNodePopulate() event, set the .SelectionAction property on the node.

TreeNode newCNode;
newCNode = new TreeNode("New Node");

newCNode.SelectAction = TreeNodeSelectAction.Select;

//now you can set the .NavigateUrl property to call the same page with some query string parameter to catch in the page_load()

newCNode.NavigateUrl = "~/ThisPage.aspx?args=" + someNodeAction

RootNode.ChildNodes.Add(newCNode);

Upvotes: 1

Larry Smithmier
Larry Smithmier

Reputation: 2731

Store what is selected and use code in the Page_Load event handler to compare what is selected to what you have stored. Page_Load is called for every post back even if the selected value doesn't change, unlike SelectedNodeChanged.

Example

alt text http://smithmier.com/TreeViewExample.png

html

<form id="form1" runat="server">
<div>
    <asp:TreeView ID="TreeView1" runat="server" OnSelectedNodeChanged="TreeView1_SelectedNodeChanged"
        ShowLines="True">
        <Nodes>
            <asp:TreeNode Text="Root" Value="Root">
                <asp:TreeNode Text="RootSub1" Value="RootSub1"></asp:TreeNode>
                <asp:TreeNode Text="RootSub2" Value="RootSub2"></asp:TreeNode>
            </asp:TreeNode>
            <asp:TreeNode Text="Root2" Value="Root2">
                <asp:TreeNode Text="Root2Sub1" Value="Root2Sub1">
                    <asp:TreeNode Text="Root2Sub1Sub1" Value="Root2Sub1Sub1"></asp:TreeNode>
                </asp:TreeNode>
                <asp:TreeNode Text="Root2Sub2" Value="Root2Sub2"></asp:TreeNode>
            </asp:TreeNode>
        </Nodes>
    </asp:TreeView>
    <asp:Label ID="Label1" runat="server" Text="Selected"></asp:Label>
    <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
    <asp:Label ID="Label2" runat="server" Text="Label"></asp:Label></div>
</form>

C#

protected void Page_Load(object sender, EventArgs e)
{
    if(TreeView1.SelectedNode!=null && this.TextBox1.Text == TreeView1.SelectedNode.Value.ToString())
    {
        Label2.Text = (int.Parse(Label2.Text) + 1).ToString();
    }
    else
    {
        Label2.Text = "0";
    }
}
protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
{
    this.TextBox1.Text = TreeView1.SelectedNode.Value.ToString();
}

Upvotes: 4

Blackadder
Blackadder

Reputation:

You can always use the MouseDown or MouseUp event and check to see if it the selected node.

Upvotes: 0

Wayne
Wayne

Reputation: 39878

Easiest way - if it doesn't interfere with the rest of your code - is to simply set the node as not selected in the SelectedNodeChanged method.

protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e){
  // Do whatever you're doing
  TreeView1.SelectedNode.Selected = false;
}

Upvotes: 9

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