DateTimePicker.DropDown Ereignis

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Tritt ein, wenn der Dropdownkalender angezeigt wird.

public:
 event EventHandler ^ DropDown;

public event EventHandler? DropDown;

member this.DropDown : EventHandler 

Public Custom Event DropDown As EventHandler 

Ereignistyp

EventHandler

Beispiele

Im folgenden Codebeispiel wird die Behandlung des DropDown Ereignisses von und DateTimePicker mithilfe der MinDateTime Felder und MaxDateTime veranschaulicht. Fügen Sie zum Ausführen dieses Beispiels den folgenden Code in ein Formular ein, das einen DateTimePicker namens DateTimePicker1enthält.

// When the calendar drops down, display a MessageBox indicating 
// that DateTimePicker will not accept dates before MinDateTime or 
// after MaxDateTime. Use a StringBuilder object to build the string
// for efficiency.
void DateTimePicker1_DropDown( Object^ /*sender*/, System::EventArgs^ /*e*/ )
{
   System::Text::StringBuilder^ messageBuilder = gcnew System::Text::StringBuilder;
   messageBuilder->Append( "Choose a date after: " );
   messageBuilder->Append( DateTimePicker::MinDateTime.ToShortDateString() );
   messageBuilder->Append( " and a date before: " );
   messageBuilder->Append( DateTimePicker::MaxDateTime.ToShortDateString() );
   MessageBox::Show( messageBuilder->ToString() );
}

// When the calendar drops down, display a MessageBox indicating 
// that DateTimePicker will not accept dates before MinDateTime or 
// after MaxDateTime. Use a StringBuilder object to build the string
// for efficiency.
private void DateTimePicker1_DropDown(object sender, 
    System.EventArgs e)
{

    System.Text.StringBuilder messageBuilder = 
        new System.Text.StringBuilder();
    messageBuilder.Append("Choose a date after: ");
    messageBuilder.Append
        (DateTimePicker.MinDateTime.ToShortDateString());
    messageBuilder.Append(" and a date before: ");
    messageBuilder.Append
        (DateTimePicker.MaxDateTime.ToShortDateString());
    MessageBox.Show(messageBuilder.ToString());
}

' When the calendar drops down, display a MessageBox indicating 
' that DateTimePicker will not accept dates before MinDateTime or 
' after MaxDateTime. Use a StringBuilder object to build the string
' for efficiency.
Private Sub DateTimePicker1_DropDown(ByVal sender As Object, _
    ByVal e As EventArgs) Handles DateTimePicker1.DropDown

    Dim messageBuilder As New System.Text.StringBuilder
    messageBuilder.Append("Choose a date after: ")
    messageBuilder.Append(DateTimePicker.MinDateTime.ToShortDateString)
    messageBuilder.Append(" and a date before: ")
    messageBuilder.Append(DateTimePicker.MaxDateTime.ToShortDateString)
    MessageBox.Show(messageBuilder.ToString())
End Sub

Hinweise

Weitere Informationen zur Behandlung von Ereignissen finden Sie unter behandeln und Auslösen von Ereignissen.

Weitere Informationen

• OnDropDown(EventArgs)