DragEventArgs.Data Eigenschaft

Definition

Ruft das IDataObject ab, das die diesem Ereignis zugeordneten Daten enthält.Gets the IDataObject that contains the data associated with this event.

public:
 property System::Windows::Forms::IDataObject ^ Data { System::Windows::Forms::IDataObject ^ get(); };
public System.Windows.Forms.IDataObject Data { get; }
member this.Data : System.Windows.Forms.IDataObject
Public ReadOnly Property Data As IDataObject

Eigenschaftswert

IDataObject

Die diesem Ereignis zugeordneten Daten.The data associated with this event.

Beispiele

Im folgenden Beispiel wird ein Drag & Drop-Vorgang zwischen zwei-Steuer ListBox Elementen veranschaulicht.The following example demonstrates a drag-and-drop operation between two ListBox controls. Im Beispiel wird die-Methode aufgerufen, DoDragDrop Wenn die Zieh Aktion gestartet wird.The example calls the DoDragDrop method when the drag action starts. Die Zieh Aktion wird gestartet, wenn die Maus SystemInformation.DragSize während des Ereignisses mehr als die Mausposition bewegt hat MouseDown .The drag action starts if the mouse has moved more than SystemInformation.DragSize from the mouse location during the MouseDown event. Die- IndexFromPoint Methode wird verwendet, um den Index des Elements zu bestimmen, das während des-Ereignisses gezogen werden soll MouseDown .The IndexFromPoint method is used to determine the index of the item to drag during the MouseDown event.

Das Beispiel zeigt auch die Verwendung von benutzerdefinierten Cursorn für den Drag & Drop-Vorgang.The example also demonstrates using custom cursors for the drag-and-drop operation. Im Beispiel wird davon ausgegangen, dass zwei Cursor Dateien, 3dwarro.cur und, 3dwno.cur im Anwendungsverzeichnis vorhanden sind, für die benutzerdefinierten Drag-und No-Drop-Cursor.The example assumes that two cursor files, 3dwarro.cur and 3dwno.cur, exist in the application directory, for the custom drag and no-drop cursors, respectively. Die benutzerdefinierten Cursor werden verwendet, wenn das UseCustomCursorsCheck CheckBox aktiviert ist.The custom cursors will be used if the UseCustomCursorsCheckCheckBox is checked. Die benutzerdefinierten Cursor werden im- GiveFeedback Ereignishandler festgelegt.The custom cursors are set in the GiveFeedback event handler.

Der Tastatur Zustand wird im DragOver Ereignishandler für das Recht ausgewertet ListBox , um zu bestimmen, welcher Zieh Vorgang auf dem Zustand der UMSCHALTTASTE, STRG, alt oder STRG + ALT-Taste basiert.The keyboard state is evaluated in the DragOver event handler for the right ListBox, to determine what the drag operation will be based upon state of the SHIFT, CTRL, ALT, or CTRL+ALT keys. Der Speicherort in der, an dem der Ablage Vorgang ListBox stattfindet, wird auch während des Ereignisses festgelegt DragOver .The location in the ListBox where the drop would occur is also determined during the DragOver event. Wenn es sich bei den zu Lösch Endes Daten nicht um handelt String , DragEventArgs.Effect wird der auf festgelegt DragDropEffects.None .If the data to drop is not a String, then the DragEventArgs.Effect is set to DragDropEffects.None. Schließlich wird der Status der Ablage in der angezeigt DropLocationLabel Label .Finally, the status of the drop is displayed in the DropLocationLabelLabel.

Die Daten, die auf der rechten Seite abgelegt werden, werden ListBox im DragDrop -Ereignishandler bestimmt, und der- String Wert wird an der entsprechenden Stelle in der hinzugefügt ListBox .The data to drop for the right ListBox is determined in the DragDrop event handler and the String value is added at the appropriate place in the ListBox. Wenn der Zieh Vorgang außerhalb der Begrenzungen des Formulars verschoben wird, wird der Drag & Drop-Vorgang im- QueryContinueDrag Ereignishandler abgebrochen.If the drag operation moves outside the bounds of the form, then the drag-and-drop operation is canceled in the QueryContinueDrag event handler.

In diesem Code Ausschnitt wird die Verwendung der- DragEventArgs Klasse veranschaulicht.This code excerpt demonstrates using the DragEventArgs class. Das gesamte Codebeispiel finden Sie unter der- DoDragDrop Methode.See the DoDragDrop method for the complete code example.

void ListDragTarget_DragOver( Object^ /*sender*/, System::Windows::Forms::DragEventArgs^ e )
{
   // Determine whether string data exists in the drop data. If not, then
   // the drop effect reflects that the drop cannot occur.
   if (  !e->Data->GetDataPresent( System::String::typeid ) )
   {
      e->Effect = DragDropEffects::None;
      DropLocationLabel->Text = "None - no string data.";
      return;
   }

   // Set the effect based upon the KeyState.
   if ( (e->KeyState & (8 + 32)) == (8 + 32) && ((e->AllowedEffect & DragDropEffects::Link) == DragDropEffects::Link) )
   {
      // KeyState 8 + 32 = CTL + ALT
      // Link drag-and-drop effect.
      e->Effect = DragDropEffects::Link;
   }
   else
   if ( (e->KeyState & 32) == 32 && ((e->AllowedEffect & DragDropEffects::Link) == DragDropEffects::Link) )
   {
      // ALT KeyState for link.
      e->Effect = DragDropEffects::Link;
   }
   else
   if ( (e->KeyState & 4) == 4 && ((e->AllowedEffect & DragDropEffects::Move) == DragDropEffects::Move) )
   {
      // SHIFT KeyState for move.
      e->Effect = DragDropEffects::Move;
   }
   else
   if ( (e->KeyState & 8) == 8 && ((e->AllowedEffect & DragDropEffects::Copy) == DragDropEffects::Copy) )
   {
      // CTL KeyState for copy.
      e->Effect = DragDropEffects::Copy;
   }
   else
   if ( (e->AllowedEffect & DragDropEffects::Move) == DragDropEffects::Move )
   {
      // By default, the drop action should be move, if allowed.
      e->Effect = DragDropEffects::Move;
   }
   else
            e->Effect = DragDropEffects::None;





   
   // Get the index of the item the mouse is below.
   // The mouse locations are relative to the screen, so they must be
   // converted to client coordinates.
   indexOfItemUnderMouseToDrop = ListDragTarget->IndexFromPoint( ListDragTarget->PointToClient( Point(e->X,e->Y) ) );
   
   // Updates the label text.
   if ( indexOfItemUnderMouseToDrop != ListBox::NoMatches )
   {
      DropLocationLabel->Text = String::Concat( "Drops before item # ", (indexOfItemUnderMouseToDrop + 1) );
   }
   else
            DropLocationLabel->Text = "Drops at the end.";
}
private void ListDragTarget_DragOver(object sender, DragEventArgs e)
{
    // Determine whether string data exists in the drop data. If not, then
    // the drop effect reflects that the drop cannot occur.
    if (!e.Data.GetDataPresent(typeof(System.String)))
    {
        e.Effect = DragDropEffects.None;
        DropLocationLabel.Text = "None - no string data.";
        return;
    }

    // Set the effect based upon the KeyState.
    if ((e.KeyState & (8 + 32)) == (8 + 32) &&
        (e.AllowedEffect & DragDropEffects.Link) == DragDropEffects.Link)
    {
        // KeyState 8 + 32 = CTL + ALT

        // Link drag-and-drop effect.
        e.Effect = DragDropEffects.Link;
    }
    else if ((e.KeyState & 32) == 32 &&
        (e.AllowedEffect & DragDropEffects.Link) == DragDropEffects.Link)
    {
        // ALT KeyState for link.
        e.Effect = DragDropEffects.Link;
    }
    else if ((e.KeyState & 4) == 4 &&
        (e.AllowedEffect & DragDropEffects.Move) == DragDropEffects.Move)
    {
        // SHIFT KeyState for move.
        e.Effect = DragDropEffects.Move;
    }
    else if ((e.KeyState & 8) == 8 &&
        (e.AllowedEffect & DragDropEffects.Copy) == DragDropEffects.Copy)
    {
        // CTL KeyState for copy.
        e.Effect = DragDropEffects.Copy;
    }
    else if ((e.AllowedEffect & DragDropEffects.Move) == DragDropEffects.Move)
    {
        // By default, the drop action should be move, if allowed.
        e.Effect = DragDropEffects.Move;
    }
    else
    {
        e.Effect = DragDropEffects.None;
    }

    // Get the index of the item the mouse is below. 

    // The mouse locations are relative to the screen, so they must be 
    // converted to client coordinates.

    indexOfItemUnderMouseToDrop =
        ListDragTarget.IndexFromPoint(ListDragTarget.PointToClient(new Point(e.X, e.Y)));

    // Updates the label text.
    if (indexOfItemUnderMouseToDrop != ListBox.NoMatches)
    {
        DropLocationLabel.Text = "Drops before item #" + (indexOfItemUnderMouseToDrop + 1);
    }
    else
    {
        DropLocationLabel.Text = "Drops at the end.";
    }
}
Private Sub ListDragTarget_DragOver(ByVal sender As Object, ByVal e As DragEventArgs) Handles ListDragTarget.DragOver
    ' Determine whether string data exists in the drop data. If not, then
    ' the drop effect reflects that the drop cannot occur.
    If Not (e.Data.GetDataPresent(GetType(System.String))) Then

        e.Effect = DragDropEffects.None
        DropLocationLabel.Text = "None - no string data."
        Return
    End If

    ' Set the effect based upon the KeyState.
    If ((e.KeyState And (8 + 32)) = (8 + 32) And
        (e.AllowedEffect And DragDropEffects.Link) = DragDropEffects.Link) Then
        ' KeyState 8 + 32 = CTL + ALT

        ' Link drag-and-drop effect.
        e.Effect = DragDropEffects.Link

    ElseIf ((e.KeyState And 32) = 32 And
        (e.AllowedEffect And DragDropEffects.Link) = DragDropEffects.Link) Then

        ' ALT KeyState for link.
        e.Effect = DragDropEffects.Link

    ElseIf ((e.KeyState And 4) = 4 And
        (e.AllowedEffect And DragDropEffects.Move) = DragDropEffects.Move) Then

        ' SHIFT KeyState for move.
        e.Effect = DragDropEffects.Move

    ElseIf ((e.KeyState And 8) = 8 And
        (e.AllowedEffect And DragDropEffects.Copy) = DragDropEffects.Copy) Then

        ' CTL KeyState for copy.
        e.Effect = DragDropEffects.Copy

    ElseIf ((e.AllowedEffect And DragDropEffects.Move) = DragDropEffects.Move) Then

        ' By default, the drop action should be move, if allowed.
        e.Effect = DragDropEffects.Move

    Else
        e.Effect = DragDropEffects.None
    End If

    ' Gets the index of the item the mouse is below. 

    ' The mouse locations are relative to the screen, so they must be 
    ' converted to client coordinates.

    indexOfItemUnderMouseToDrop =
        ListDragTarget.IndexFromPoint(ListDragTarget.PointToClient(New Point(e.X, e.Y)))

    ' Updates the label text.
    If (indexOfItemUnderMouseToDrop <> ListBox.NoMatches) Then
        DropLocationLabel.Text = "Drops before item #" & (indexOfItemUnderMouseToDrop + 1)
    Else
        DropLocationLabel.Text = "Drops at the end."
    End If

End Sub

Hinweise

Im Text des Ereignis Handlers können Sie mithilfe der- GetDataPresent Methode ermitteln, ob die Daten mit den Formatanforderungen des Steuer Elements übereinstimmen, an das die Daten gezogen werden.In the body of your event handler, you can use the GetDataPresent method to determine whether the data matches the format requirements of the control onto which the data is being dragged. Sie können auch angeben, ob Sie versuchen möchten, die Daten zu konvertieren, um Ihre Formatanforderungen zu erfüllen.You also can specify whether you want to attempt to convert the data to meet your format requirements. Wenn die gezogenen Daten Ihren Formatanforderungen entsprechen, verwenden Sie die- GetData Methode, um die Daten abzurufen.If the dragged data meets your format requirements, use the GetData method to retrieve the data.

Gilt für:

Siehe auch