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GiveFeedbackEventArgs Classe

Provides data for the GiveFeedback event, which occurs during a drag operation.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (em System.Windows.Forms. dll)

[ComVisibleAttribute(true)]
public class GiveFeedbackEventArgs : EventArgs

The GiveFeedback event occurs during a drag operation.It allows the origem of a evento de arrastar to modify the aparência of the ponteiro do mouse in Ordem to give the comentários visuais do usuário During a drag-and-Soltar operation.A GiveFeedbackEventArgs object specifies the type of drag-and-drop operation and whether default cursors are used.

For information about the event model, see Eventos e representantes.

The following example demonstrates a drag-and-drop operation between two ListBox controls.The example calls the DoDragDrop method when the drag action starts.The drag action starts if the mouse has moved more than SystemInformation.DragSize from the mouse location during the MouseDown event.The IndexFromPoint method is used to determine the index of the item to drag during the MouseDown event.

O exemplo também demonstra o uso Cursores Personalizars para a operação arrastar-e-soltar.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.The custom cursors will be used if the UseCustomCursorsCheckCheckBox is checked.The custom cursors are set in the GiveFeedback event handler.

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.The location in the ListBox where the drop would occur is also determined during the DragOver event.If the data to drop is not a String, then the DragEventArgs.Effect is set to DragDropEffects.None.Finally, the status of the drop is displayed in the DropLocationLabelLabel.

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.If the drag operation moves outside the bounds of the form, then the drag-and-drop operation is canceled in the QueryContinueDrag event handler.

This code excerpt demonstrates using the GiveFeedbackEventArgs class.See the DoDragDrop method for the complete code example.

private void ListDragSource_GiveFeedback(object sender, System.Windows.Forms.GiveFeedbackEventArgs e) 
{
    // Use custom cursors if the check box is checked.
    if (UseCustomCursorsCheck.Checked) {

        // Sets the custom cursor based upon the effect.
        e.UseDefaultCursors = false;
        if ((e.Effect & DragDropEffects.Move) == DragDropEffects.Move)
            Cursor.Current = MyNormalCursor;
        else 
            Cursor.Current = MyNoDropCursor;
    }

}


private void listDragSource_GiveFeedback(Object sender, 
    System.Windows.Forms.GiveFeedbackEventArgs e)
{
    // Use custom cursors if the check box is checked.
    if (useCustomCursorsCheck.get_Checked()) {
        // Sets the custom cursor based upon the effect.
        e.set_UseDefaultCursors(false);
        if ((e.get_Effect() & DragDropEffects.Move) 
            == DragDropEffects.Move) {
            get_Cursor().set_Current(myNormalCursor);
        }
        else {
            get_Cursor().set_Current(myNoDropCursor);
        }
    }
} //listDragSource_GiveFeedback


System.Object
  System.EventArgs
    System.Windows.Forms.GiveFeedbackEventArgs

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