TreeNode.BeginEdit Metode

Definisi

Ruang nama:

System.Windows.Forms

Rakitan:

System.Windows.Forms.dll

Memulai pengeditan label simpul pohon.

public:
 void BeginEdit();

public void BeginEdit ();

member this.BeginEdit : unit -> unit

Public Sub BeginEdit ()

Pengecualian

InvalidOperationException

LabelEdit diatur ke false.

Contoh

Contoh kode berikut memungkinkan pengguna mengedit simpul pohon nonroot dengan menggunakan ContextMenu. Ketika pengguna mengklik kanan mouse, pada posisi tersebut TreeNode ditentukan dan disimpan dalam variabel bernama mySelectedNode. Jika simpul pohon nonroot dipilih, simpul tersebut dimasukkan ke dalam status dapat diedit, memungkinkan pengguna mengedit label simpul. Setelah pengguna berhenti mengedit label simpul pohon, teks label baru dievaluasi dan disimpan. Untuk contoh ini, beberapa karakter dianggap tidak valid dalam teks label. Jika salah satu karakter yang tidak valid berada dalam string label, atau string kosong, pengguna akan diberi tahu tentang kesalahan dan label dikembalikan ke teks sebelumnya.

   /* 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();
         }
      }
   }

/* 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();
     }
   }
}

' 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
   End If
End Sub

Keterangan

Skenario umum untuk menggunakan metode ini adalah memanggilnya pada Click peristiwa MenuItem atau ContextMenu.

Catatan

Metode ini hanya berfungsi jika LabelEdit properti diatur TreeView ke true. Jika LabelEdit diatur ke false, pengecualian dilemparkan dan simpul pohon tidak akan dimasukkan ke dalam status dapat diedit.

Lihat juga

• EndEdit(Boolean)
• IsEditing