DragEventArgs.KeyState DragEventArgs.KeyState DragEventArgs.KeyState DragEventArgs.KeyState Property

Definición

Obtiene el estado actual de las teclas MAYÚS, CTRL y ALT, así como el estado de los botones del mouse.Gets the current state of the SHIFT, CTRL, and ALT keys, as well as the state of the mouse buttons.

public:
 property int KeyState { int get(); };
public int KeyState { get; }
member this.KeyState : int
Public ReadOnly Property KeyState As Integer

Valor de propiedad

Estado actual de las teclas MAYÚS, CTRL y ALT y de los botones del mouse.The current state of the SHIFT, CTRL, and ALT keys and of the mouse buttons.

Ejemplos

En el ejemplo siguiente se muestra una operación de arrastrar y colocar entre ListBox dos controles.The following example demonstrates a drag-and-drop operation between two ListBox controls. En el ejemplo se DoDragDrop llama al método cuando se inicia la acción de arrastrar.The example calls the DoDragDrop method when the drag action starts. La acción de arrastrar comienza si el mouse ha pasado más SystemInformation.DragSize de la ubicación del mouse durante MouseDown el evento.The drag action starts if the mouse has moved more than SystemInformation.DragSize from the mouse location during the MouseDown event. El IndexFromPoint método se utiliza para determinar el índice del elemento que se va a arrastrar MouseDown durante el evento.The IndexFromPoint method is used to determine the index of the item to drag during the MouseDown event.

En el ejemplo también se muestra el uso de cursores personalizados para la operación de arrastrar y colocar.The example also demonstrates using custom cursors for the drag-and-drop operation. En el ejemplo se da por supuesto que 3dwarro.cur dos 3dwno.curarchivos de cursor, y, existen en el directorio de la aplicación para los cursores de arrastrar y no colocar personalizados, respectivamente.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. Se usarán los cursores personalizados si UseCustomCursorsCheck CheckBox está activado.The custom cursors will be used if the UseCustomCursorsCheckCheckBox is checked. Los cursores personalizados se establecen en el GiveFeedback controlador de eventos.The custom cursors are set in the GiveFeedback event handler.

El estado del teclado se evalúa en DragOver el controlador de eventos de ListBoxla derecha, para determinar qué operación de arrastre se basará en el estado de las teclas Mayús, Ctrl, Alt o Ctrl + Alt.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. La ubicación en ListBox donde se produciría la colocación también se determina durante el DragOver evento.The location in the ListBox where the drop would occur is also determined during the DragOver event. Si los datos que se van a quitar Stringno son, DragEventArgs.Effect el se establece DragDropEffects.Noneen.If the data to drop is not a String, then the DragEventArgs.Effect is set to DragDropEffects.None. Por último, el estado de la eliminación se muestra en DropLocationLabel. LabelFinally, the status of the drop is displayed in the DropLocationLabelLabel.

Los datos que se van a quitar ListBox para el derecho se DragDrop determinan en String el controlador de eventos y el valor ListBoxse agrega en el lugar adecuado en.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. Si la operación de arrastre se mueve fuera de los límites del formulario, la operación de arrastrar y colocar se cancela en el QueryContinueDrag controlador de eventos.If the drag operation moves outside the bounds of the form, then the drag-and-drop operation is canceled in the QueryContinueDrag event handler.

En este fragmento de código se DragEventArgs muestra cómo usar la clase.This code excerpt demonstrates using the DragEventArgs class. Vea el DoDragDrop método para obtener el ejemplo de código completo.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

Comentarios

Puede hacer que el efecto de una operación de arrastrar y colocar dependa del estado de una clave determinada.You can make the effect of a drag-and-drop operation to depend on the state of a particular key. Por ejemplo, puede decidir copiar o mover datos dependiendo de si se presionan las teclas CTRL o Mayús durante la operación de arrastrar y colocar.For example, you may decide to copy or move data depending on whether the CTRL or SHIFT keys are pressed during the drag-and-drop operation.

Los bits que se establecen en la KeyState propiedad identifican las teclas o los botones del mouse que se presionaron durante la operación.The bits that are set in the KeyState property identify the keys or mouse buttons that were pressed during the operation. Por ejemplo, si se presiona el botón primario del mouse, se establece el primer KeyState bit de la propiedad.For example, if the left mouse button is pressed, the first bit in the KeyState property is set. Puede usar el operador and bit a bit para probar un estado de clave determinado.You can use the bitwise AND operator to test for a given key state.

En la tabla siguiente se enumeran los valores que se usan para un evento especificado.The following table lists the values that are used for a specified event.

ValorValue KeyKey
1 (bit 0)1 (bit 0) Botón primario del mouse.The left mouse button.
2 (bit 1)2 (bit 1) Botón secundario del mouse.The right mouse button.
4 (bit 2)4 (bit 2) Tecla MAYÚS.The SHIFT key.
8 (bit 3)8 (bit 3) Tecla CTRL.The CTRL key.
16 (bit 4)16 (bit 4) Botón central del mouse.The middle mouse button.
32 (bit 5)32 (bit 5) Tecla ALT.The ALT key.

Se aplica a