TrackBar.ValueChanged Événement

Définition

Espace de noms:
System.Windows.Forms
Assembly:
System.Windows.Forms.dll
Source:
TrackBar.cs
Source:
TrackBar.cs
Source:
TrackBar.cs
Source:
TrackBar.cs
Source:
TrackBar.cs

Se produit lorsque la Value propriété d’une barre de suivi change, soit par mouvement de la zone de défilement, soit par manipulation dans le code.

public:
 event EventHandler ^ ValueChanged;
public event EventHandler ValueChanged;
public event EventHandler? ValueChanged;
member this.ValueChanged : EventHandler 
Public Custom Event ValueChanged As EventHandler

Type d'événement

EventHandler

Exemples

L’exemple de code suivant montre comment utiliser les membres TickStyleet Minimum les Maximummembres et comment gérer l’événementValueChanged. Pour exécuter l’exemple, collez le code suivant dans un formulaire qui contient un TrackBar nom TrackBar1 de contrôle et un TextBox contrôle nommé TextBox1. Appelez la InitializeTrackBar méthode à partir du constructeur du formulaire ou Load de la méthode de gestion des événements.

   //Declare a new TrackBar object.
internal:
   System::Windows::Forms::TrackBar^ TrackBar1;

   // Initialize the TrackBar and add it to the form.
private:
   void InitializeTrackBar()
   {
      this->TrackBar1 = gcnew System::Windows::Forms::TrackBar;
      TrackBar1->Location = System::Drawing::Point( 75, 30 );
      
      // Set the TickStyle property so there are ticks on both sides
      // of the TrackBar.
      TrackBar1->TickStyle = TickStyle::Both;
      
      // Set the minimum and maximum number of ticks.
      TrackBar1->Minimum = 10;
      TrackBar1->Maximum = 100;
      
      // Set the tick frequency to one tick every ten units.
      TrackBar1->TickFrequency = 10;
      
      // Associate the event-handling method with the 
      // ValueChanged event.
      TrackBar1->ValueChanged += gcnew System::EventHandler( this, &Form1::TrackBar1_ValueChanged );
      this->Controls->Add( this->TrackBar1 );
   }

   // Handle the TrackBar.ValueChanged event by calculating a value for
   // TextBox1 based on the TrackBar value.  
   void TrackBar1_ValueChanged( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      TextBox1->Text = (System::Math::Round( TrackBar1->Value / 10.0 )).ToString();
   }


//Declare a new TrackBar object.
internal System.Windows.Forms.TrackBar TrackBar1;

// Initialize the TrackBar and add it to the form.
private void InitializeTrackBar()
{
    this.TrackBar1 = new System.Windows.Forms.TrackBar();
    TrackBar1.Location = new System.Drawing.Point(75, 30);

    // Set the TickStyle property so there are ticks on both sides
    // of the TrackBar.
    TrackBar1.TickStyle = TickStyle.Both;

    // Set the minimum and maximum number of ticks.
    TrackBar1.Minimum = 10;
    TrackBar1.Maximum = 100;

    // Set the tick frequency to one tick every ten units.
    TrackBar1.TickFrequency = 10;

    // Associate the event-handling method with the 
    // ValueChanged event.
    TrackBar1.ValueChanged += 
        new System.EventHandler(TrackBar1_ValueChanged);
    this.Controls.Add(this.TrackBar1);
}

// Handle the TrackBar.ValueChanged event by calculating a value for
// TextBox1 based on the TrackBar value.  
private void TrackBar1_ValueChanged(object sender, System.EventArgs e)
{
    TextBox1.Text = (System.Math.Round(TrackBar1.Value/10.0)).ToString();
}


'Declare a new TrackBar object.
Friend WithEvents TrackBar1 As System.Windows.Forms.TrackBar

' Initialize the TrackBar and add it to the form.
Private Sub InitializeTrackBar()
    Me.TrackBar1 = New System.Windows.Forms.TrackBar

    ' Set the TickStyle property so there are ticks on both sides
    ' of the TrackBar.
    TrackBar1.TickStyle = TickStyle.Both

    ' Set the minimum and maximum number of ticks.
    TrackBar1.Minimum = 10
    TrackBar1.Maximum = 100

    ' Set the tick frequency to one tick every ten units.
    TrackBar1.TickFrequency = 10

    TrackBar1.Location = New System.Drawing.Point(75, 30)
    Me.Controls.Add(Me.TrackBar1)
End Sub


' Handle the TrackBar.ValueChanged event by calculating a value for
' TextBox1 based on the TrackBar value.  
Private Sub TrackBar1_ValueChanged(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles TrackBar1.ValueChanged
    TextBox1.Text = System.Math.Round(TrackBar1.Value / 10)
End Sub

Remarques

Vous pouvez utiliser cet événement pour mettre à jour d’autres contrôles lorsque la valeur représentée dans la barre de suivi change.

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

S’applique à