TrackBar.ValueChanged Evento

Definición

Espacio de nombres:

System.Windows.Forms

Ensamblado:

System.Windows.Forms.dll

Se produce cuando cambia la propiedad Value de una barra de seguimiento, ya sea por el movimiento del cuadro de desplazamiento o por una manipulación del código.

public:
 event EventHandler ^ ValueChanged;

public event EventHandler? ValueChanged;

member this.ValueChanged : EventHandler 

Public Custom Event ValueChanged As EventHandler 

Tipo de evento

EventHandler

Ejemplos

En el ejemplo de código siguiente se muestra cómo usar los TickStylemiembros , Minimumy Maximum y cómo controlar el ValueChanged evento. Para ejecutar el ejemplo, pegue el código siguiente en un formulario que contenga un TrackBar nombre TrackBar1 de control y un TextBox control denominado TextBox1. Llame al método desde el InitializeTrackBar constructor Load o el método de control de eventos del formulario.

   //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

Comentarios

Puede usar este evento para actualizar otros controles cuando cambia el valor representado en la barra de seguimiento.

Para obtener más información sobre el manejo de eventos, consulte controlar y provocar eventos.