NodeLabelEditEventArgs 类

提供有关 BeforeLabelEdit 和 AfterLabelEdit 事件的数据。

**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）

语法

声明
Public Class NodeLabelEditEventArgs
    Inherits EventArgs
用法
Dim instance As NodeLabelEditEventArgs

public class NodeLabelEditEventArgs : EventArgs

public ref class NodeLabelEditEventArgs : public EventArgs

public class NodeLabelEditEventArgs extends EventArgs

public class NodeLabelEditEventArgs extends EventArgs

备注

用户完成对树节点文本的编辑时发生 AfterLabelEdit 事件。用户开始对树节点进行编辑时发生 BeforeLabelEdit 事件。NodeLabelEditEventArgs 对象指定以下内容：与树节点相关联的新文本，包含待编辑标签的树节点，以及是否已取消编辑操作。

有关处理事件的更多信息，请参见 使用事件。

示例

下面的示例允许用户使用 ContextMenu 编辑非根树节点。当用户右击鼠标时，即可确定该位置的 TreeNode，并将其存储在一个名为 mySelectedNode 的变量中。如果选择了非根树节点，则它被置于可编辑状态，允许用户编辑节点标签。用户停止编辑树节点标签后，将计算新的标签文本并予以保存。对于本示例，多个字符在标签文本中无效。如果标签字符串中有一个无效字符，或者该字符串为空，则将向用户通知错误，同时标签返回到其以前的文本。

' 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.X, e.Y);
}

private void menuItem1_Click(object sender, System.EventArgs e)
{
   if (mySelectedNode != null && mySelectedNode.Parent != null)
   {
      treeView1.SelectedNode = mySelectedNode;
      treeView1.LabelEdit = true;
      if(!mySelectedNode.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");
   }
}

private void treeView1_AfterLabelEdit(object sender, 
         System.Windows.Forms.NodeLabelEditEventArgs e)
{
   if (e.Label != null)
   {
     if(e.Label.Length > 0)
     {
        if (e.Label.IndexOfAny(new char[]{'@', '.', ',', '!'}) == -1)
        {
           // 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.\n" + 
              "The invalid characters are: '@','.', ',', '!'", 
              "Node Label Edit");
           e.Node.BeginEdit();
        }
     }
     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.\nThe label cannot be blank", 
           "Node Label Edit");
        e.Node.BeginEdit();
     }
     this.treeView1.LabelEdit = false;
   }
}

   /* 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->X, e->Y );
   }

   void menuItem1_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      if ( mySelectedNode != nullptr && mySelectedNode->Parent != nullptr )
      {
         treeView1->SelectedNode = mySelectedNode;
         treeView1->LabelEdit = true;
         if (  !mySelectedNode->IsEditing )
         {
            mySelectedNode->BeginEdit();
         }
      }
      else
      {
         MessageBox::Show( String::Concat( "No tree node selected or selected node is a root node.\n",
            "Editing of root nodes is not allowed." ), "Invalid selection" );
      }
   }

   void treeView1_AfterLabelEdit( Object^ /*sender*/,
      System::Windows::Forms::NodeLabelEditEventArgs^ e )
   {
      if ( e->Label != nullptr )
      {
         if ( e->Label->Length > 0 )
         {
            array<Char>^ temp0 = {'@','.',',','!'};
            if ( e->Label->IndexOfAny( temp0 ) == -1 )
            {
               
               // 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( String::Concat( "Invalid tree node label.\n",
                  "The invalid characters are: '@','.', ',', '!'" ),
                  "Node Label Edit" );
               e->Node->BeginEdit();
            }
         }
         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.\nThe label cannot be blank",
               "Node Label Edit" );
            e->Node->BeginEdit();
         }
         this->treeView1->LabelEdit = false;
      }
   }

/* 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

继承层次结构

System.Object
   System.EventArgs
    System.Windows.Forms.NodeLabelEditEventArgs

线程安全

此类型的任何公共静态（Visual Basic 中的 Shared）成员都是线程安全的，但不保证所有实例成员都是线程安全的。

平台

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

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

请参见

参考

NodeLabelEditEventArgs 成员
System.Windows.Forms 命名空间
NodeLabelEditEventHandler
BeforeLabelEdit
AfterLabelEdit