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TreeView.AfterCheck Événement

  • Référence

Définition

Espace de noms:
System.Windows.Forms
Assembly:
System.Windows.Forms.dll

Se produit après que la case du nœud d'arbre a été cochée.

public:
 event System::Windows::Forms::TreeViewEventHandler ^ AfterCheck;
public event System.Windows.Forms.TreeViewEventHandler AfterCheck;
public event System.Windows.Forms.TreeViewEventHandler? AfterCheck;
member this.AfterCheck : System.Windows.Forms.TreeViewEventHandler 
Public Custom Event AfterCheck As TreeViewEventHandler

Type d'événement

TreeViewEventHandler

Exemples

L’exemple de code suivant met à jour tous les nœuds d’arborescence enfants d’un TreeNode lorsque l’utilisateur change son état vérifié. Ce code nécessite que vous ayez un Form avec un qui a TreeNode des TreeView objets dans son TreeNodeCollection. Doit avoir des TreeNodeCollection nœuds d’arborescence avec des nœuds enfants.

// Updates all child tree nodes recursively.
void CheckAllChildNodes( TreeNode^ treeNode, bool nodeChecked )
{
   IEnumerator^ myEnum = treeNode->Nodes->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      TreeNode^ node = safe_cast<TreeNode^>(myEnum->Current);
      node->Checked = nodeChecked;
      if ( node->Nodes->Count > 0 )
      {
         
         // If the current node has child nodes, call the CheckAllChildsNodes method recursively.
         this->CheckAllChildNodes( node, nodeChecked );
      }
   }
}

// NOTE   This code can be added to the BeforeCheck event handler instead of the AfterCheck event.
// After a tree node's Checked property is changed, all its child nodes are updated to the same value.
void node_AfterCheck( Object^ /*sender*/, TreeViewEventArgs^ e )
{
   // The code only executes if the user caused the checked state to change.
   if ( e->Action != TreeViewAction::Unknown )
   {
      if ( e->Node->Nodes->Count > 0 )
      {
         /* Calls the CheckAllChildNodes method, passing in the current
             Checked value of the TreeNode whose checked state changed. */
         this->CheckAllChildNodes( e->Node, e->Node->Checked );
      }
   }
}

// Updates all child tree nodes recursively.
private void CheckAllChildNodes(TreeNode treeNode, bool nodeChecked)
{
   foreach(TreeNode node in treeNode.Nodes)
   {
      node.Checked = nodeChecked;
      if(node.Nodes.Count > 0)
      {
         // If the current node has child nodes, call the CheckAllChildsNodes method recursively.
         this.CheckAllChildNodes(node, nodeChecked);
      }
   }
}

// NOTE   This code can be added to the BeforeCheck event handler instead of the AfterCheck event.
// After a tree node's Checked property is changed, all its child nodes are updated to the same value.
private void node_AfterCheck(object sender, TreeViewEventArgs e)
{
   // The code only executes if the user caused the checked state to change.
   if(e.Action != TreeViewAction.Unknown)
   {
      if(e.Node.Nodes.Count > 0)
      {
         /* Calls the CheckAllChildNodes method, passing in the current 
         Checked value of the TreeNode whose checked state changed. */
         this.CheckAllChildNodes(e.Node, e.Node.Checked);
      }
   }
}

' Updates all child tree nodes recursively.
Private Sub CheckAllChildNodes(treeNode As TreeNode, nodeChecked As Boolean)
   Dim node As TreeNode
   For Each node In  treeNode.Nodes 
      node.Checked = nodeChecked
      If node.Nodes.Count > 0 Then
         ' If the current node has child nodes, call the CheckAllChildsNodes method recursively.
         Me.CheckAllChildNodes(node, nodeChecked)
      End If
   Next node
End Sub
      
' NOTE   This code can be added to the BeforeCheck event handler instead of the AfterCheck event.
' After a tree node's Checked property is changed, all its child nodes are updated to the same value.
Private Sub node_AfterCheck(sender As Object, e As TreeViewEventArgs) Handles treeView1.AfterCheck
   ' The code only executes if the user caused the checked state to change.
   If e.Action <> TreeViewAction.Unknown Then 
      If e.Node.Nodes.Count > 0 Then
         ' Calls the CheckAllChildNodes method, passing in the current 
         ' Checked value of the TreeNode whose checked state changed. 
         Me.CheckAllChildNodes(e.Node, e.Node.Checked)
      End If
   End If
End Sub

Remarques

La définition de la TreeNode.Checked propriété à partir d’un gestionnaire d’événements ou AfterCheck entraîne la levée de l’événement plusieurs fois et peut entraîner un BeforeCheck comportement inattendu. Pour empêcher la levée de l’événement plusieurs fois, ajoutez une logique à votre gestionnaire d’événements qui exécute uniquement votre code récursif si la Action propriété du TreeViewEventArgs n’est pas définie sur TreeViewAction.Unknown.

Pour plus d'informations sur la gestion des événements, voir gestion et déclenchement d’événements.

S’applique à

Voir aussi