TreeNode.FirstNode Property

Gets the first child tree node in the tree node collection.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

public TreeNode FirstNode { get; }
/** @property */
public TreeNode get_FirstNode ()

public function get FirstNode () : TreeNode

Property Value

The first child TreeNode in the Nodes collection.

The FirstNode is the first child TreeNode in the TreeNodeCollection stored in the Nodes property of the current tree node. If the TreeNode has no child tree node, the FirstNode property returns a null reference (Nothing in Visual Basic).

The following code example selects the appropriate TreeNode after determining if the TreeNode passed in is selected and which TreeNode to select. This example requires that you have a Form with a TreeView control that has a TreeNodeCollection containing several TreeNode objects. It also requires that you have a ComboBox with the following items: "Previous", "PreviousVisible", "Next", "NextVisible", "First", and "Last".

private void SelectNode(TreeNode node)
{
    if(node.IsSelected)
    {
        // Determine which TreeNode to select.
        switch(myComboBox.Text)
        {
            case "Previous":
                node.TreeView.SelectedNode = node.PrevNode;
                break;
            case "PreviousVisible":
                node.TreeView.SelectedNode = node.PrevVisibleNode;
                break;
            case "Next":
                node.TreeView.SelectedNode = node.NextNode;
                break;
            case "NextVisible":
                node.TreeView.SelectedNode = node.NextVisibleNode;
                break;
            case "First":
                node.TreeView.SelectedNode = node.FirstNode;
                break;
            case "Last":
                node.TreeView.SelectedNode = node.LastNode;
                break;
        }
    }
    node.TreeView.Focus();
}

private void SelectNode(TreeNode node)
{
    if (node.get_IsSelected()) {
        // Determine which TreeNode to select.
        if (myComboBox.get_Text().Equals("Previous")) {
            node.get_TreeView().set_SelectedNode(node.get_PrevNode());
        }
        else {
            if (myComboBox.get_Text().Equals("PreviousVisible")) {
                node.get_TreeView().set_SelectedNode(node.
                    get_PrevVisibleNode());
            }
            else {
                if (myComboBox.get_Text().Equals("Next")) {
                    node.get_TreeView().set_SelectedNode(node.get_NextNode());
                }
                else {
                    if (myComboBox.get_Text().Equals("NextVisible")) {
                        node.get_TreeView().set_SelectedNode(
                            node.get_NextVisibleNode());
                    }
                    else {
                        if (myComboBox.get_Text().Equals("First")) {
                            node.get_TreeView().set_SelectedNode(
                                node.get_FirstNode());
                        }
                        else {
                            if (myComboBox.get_Text().Equals("Last")) {
                                node.get_TreeView().set_SelectedNode(
                                    node.get_LastNode());
                            }
                        }
                    }
                }
            }
        }
    }
    node.get_TreeView().Focus();
} //SelectNode

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

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