DragEventArgs.Effect DragEventArgs.Effect DragEventArgs.Effect DragEventArgs.Effect Property

定義

ドラッグ アンド ドロップ操作のターゲットのドロップ効果を取得または設定します。Gets or sets the target drop effect in a drag-and-drop operation.

public:
 property System::Windows::Forms::DragDropEffects Effect { System::Windows::Forms::DragDropEffects get(); void set(System::Windows::Forms::DragDropEffects value); };
public System.Windows.Forms.DragDropEffects Effect { get; set; }
member this.Effect : System.Windows.Forms.DragDropEffects with get, set
Public Property Effect As DragDropEffects

プロパティ値

次の例では、2 つの間でドラッグ アンド ドロップ操作ListBoxコントロール。The following example demonstrates a drag-and-drop operation between two ListBox controls. 例では、DoDragDropドラッグ操作の開始メソッド。The example calls the DoDragDrop method when the drag action starts. ドラッグ操作の開始、マウスが移動した場合は、複数のSystemInformation.DragSize中にマウスの位置から、MouseDownイベント。The drag action starts if the mouse has moved more than SystemInformation.DragSize from the mouse location during the MouseDown event. IndexFromPointメソッドを使用中にドラッグする項目のインデックスを確認して、MouseDownイベント。The IndexFromPoint method is used to determine the index of the item to drag during the MouseDown event.

例では、カスタム カーソルをドラッグ アンド ドロップ操作を使用しても示しています。The example also demonstrates using custom cursors for the drag-and-drop operation. この例ではその 2 つカーソル ファイル、3dwarro.cur3dwno.cur、カスタム ドラッグ用のアプリケーション ディレクトリ内に存在および非ドロップ カーソルの場合、それぞれします。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. 場合に使用されるカスタム カーソル、 UseCustomCursorsCheck CheckBoxがチェックされます。The custom cursors will be used if the UseCustomCursorsCheckCheckBox is checked. カスタム カーソルが設定されて、GiveFeedbackイベント ハンドラー。The custom cursors are set in the GiveFeedback event handler.

キーボードの状態が評価される、DragOver右側のイベント ハンドラー ListBox、ドラッグ操作を決定する SHIFT、CTRL、alt キーを押し、または CTRL + ALT キーの状態に基づいています。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. 内の場所、ListBox中にも決定されますが、ドロップが発生、DragOverイベント。The location in the ListBox where the drop would occur is also determined during the DragOver event. 削除するデータがない場合、 StringDragEventArgs.Effectに設定されているDragDropEffects.Noneします。If the data to drop is not a String, then the DragEventArgs.Effect is set to DragDropEffects.None. ドロップダウンの状態を表示する最後に、 DropLocationLabelLabelします。Finally, the status of the drop is displayed in the DropLocationLabelLabel.

右側のドロップするデータListBoxで決定されます、DragDropイベント ハンドラーとStringの適切な場所にある値を追加、ListBoxします。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. ドラッグ操作が、フォームの境界の外側に移動しでドラッグ アンド ドロップ操作を取り消したかどうか、QueryContinueDragイベント ハンドラー。If the drag operation moves outside the bounds of the form, then the drag-and-drop operation is canceled in the QueryContinueDrag event handler.

このコードの抜粋では、使用方法を示します、DragEventArgsクラス。This code excerpt demonstrates using the DragEventArgs class. 参照してください、DoDragDrop完全なコード例のメソッド。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, 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(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

注釈

既定では、適用された効果は、ドラッグ アンド ドロップ操作の対象のマウス カーソルを決定します。By default, the effect applied determines the mouse cursor for the target of a drag-and-drop operation. これは、実行される操作のユーザーにフィードバックを提供するのに便利です。This is useful to provide feedback to the user on the operation that will occur. たとえば場合は、元のファイルをドラッグすると、CTRL キーを押すと、指定DragDropEffects.Copyを示す、ターゲットは、コピー操作を実行しようとしています。For example, if you press the CTRL key when you drag a file from a source, specify DragDropEffects.Copy to indicate the target will try to perform a copy operation.

ドラッグ操作にカスタムのカーソルを使用する、次を参照してください。GiveFeedbackEventArgs.UseDefaultCursorsします。To use custom cursors for a drag operation, see GiveFeedbackEventArgs.UseDefaultCursors.

適用対象

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