NodeLabelEditEventArgs Class
Assembly: System.Windows.Forms (in system.windows.forms.dll)
The AfterLabelEdit event occurs when the user finishes editing the text for a tree node. The BeforeLabelEdit event occurs when the user begins editing the text for a tree node. A NodeLabelEditEventArgs object specifies the new text to associate with the tree node, the tree node that contains the label to edit, and whether the edit operation has been canceled.
For more information about handling events, see Consuming Events.
The following example allows the user to edit nonroot tree nodes by using a ContextMenu. When the user right clicks the mouse, the TreeNode at that position is determined and stored in a variable named mySelectedNode. If a nonroot tree node was selected, it is put into an editable state, allowing the user to edit the node label. After the user stops editing the tree node label, the new label text is evaluated and saved. For this example, several characters are considered not valid in the label text. If one of the invalid characters is in the label string, or the string is empty, the user is notified of the error and the label is returned to its previous text.
' Get the tree node under the mouse pointer and ' save it in the mySelectedNode variable. Private Sub treeView1_MouseDown(sender As Object, _ e As System.Windows.Forms.MouseEventArgs) mySelectedNode = treeView1.GetNodeAt(e.X, e.Y) End Sub Private Sub menuItem1_Click(sender As Object, e As System.EventArgs) If Not (mySelectedNode Is Nothing) And _ Not (mySelectedNode.Parent Is Nothing) Then treeView1.SelectedNode = mySelectedNode treeView1.LabelEdit = True If Not mySelectedNode.IsEditing Then mySelectedNode.BeginEdit() End If Else MessageBox.Show("No tree node selected or selected node is a root node." & _ Microsoft.VisualBasic.ControlChars.Cr & _ "Editing of root nodes is not allowed.", "Invalid selection") End If End Sub Private Sub treeView1_AfterLabelEdit(sender As Object, _ e As System.Windows.Forms.NodeLabelEditEventArgs) If Not (e.Label Is Nothing) Then If e.Label.Length > 0 Then If e.Label.IndexOfAny(New Char() {"@"c, "."c, ","c, "!"c}) = -1 Then ' Stop editing without canceling the label change. e.Node.EndEdit(False) Else ' Cancel the label edit action, inform the user, and ' place the node in edit mode again. e.CancelEdit = True MessageBox.Show("Invalid tree node label." & _ Microsoft.VisualBasic.ControlChars.Cr & _ "The invalid characters are: '@','.', ',', '!'", _ "Node Label Edit") e.Node.BeginEdit() End If Else ' Cancel the label edit action, inform the user, and ' place the node in edit mode again. e.CancelEdit = True MessageBox.Show("Invalid tree node label." & _ Microsoft.VisualBasic.ControlChars.Cr & _ "The label cannot be blank", "Node Label Edit") e.Node.BeginEdit() End If Me.treeView1.LabelEdit = False End If End Sub
/* Get the tree node under the mouse pointer and
save it in the mySelectedNode variable.
*/
private void treeView1_MouseDown(Object sender,
System.Windows.Forms.MouseEventArgs e)
{
mySelectedNode = treeView1.GetNodeAt(e.get_X(), e.get_Y());
} //treeView1_MouseDown
private void menuItem1_Click(Object sender, System.EventArgs e)
{
if (mySelectedNode != null && mySelectedNode.get_Parent() != null) {
treeView1.set_SelectedNode(mySelectedNode);
treeView1.set_LabelEdit(true);
if (!(mySelectedNode.get_IsEditing())) {
mySelectedNode.BeginEdit();
}
}
else {
MessageBox.Show("No tree node selected or selected node"
+ "is a root node.\n"
+ "Editing of root nodes is not allowed.", "Invalid selection");
}
} //menuItem1_Click
private void treeView1_AfterLabelEdit(Object sender,
System.Windows.Forms.NodeLabelEditEventArgs e)
{
if (e.get_Label()!= null) {
if (e.get_Label().length() > 0) {
if (e.get_Label().IndexOfAny((new char[]{ '@', '.', ',', '!' }))
== -1) {
// Stop editing without canceling the label change.
e.get_Node().EndEdit(false);
}
else {
/* Cancel the label edit action, inform the user, and
place the node in edit mode again.
*/
e.set_CancelEdit(true);
MessageBox.Show("Invalid tree node label.\n"
+ "The invalid characters are: "
+ "'@','.', ',', '!'", "Node Label Edit");
e.get_Node().BeginEdit();
}
}
else {
/* Cancel the label edit action, inform the user, and
place the node in edit mode again.
*/
e.set_CancelEdit(true);
MessageBox.Show("Invalid tree node label.\n"
+ "The label cannot be blank", "Node Label Edit");
e.get_Node().BeginEdit();
}
this.treeView1.set_LabelEdit(false);
}
} //treeView1_AfterLabelEdit
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.