KeyEventArgs.Alt 屬性

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

取得值，指出是否按下 ALT 鍵。

public:
 virtual property bool Alt { bool get(); };

public virtual bool Alt { get; }

member this.Alt : bool

Public Overridable ReadOnly Property Alt As Boolean

屬性值

Boolean

如果按下 ALT 鍵則為 true，否則為 false。

範例

範例 1

下列程式碼範例示範如何使用 KeyDown 事件搭配 Help 類別，向使用者顯示快顯樣式說明。 此範例會使用 KeyEventArgs 傳遞至事件處理常式方法的屬性，篩選使用修飾詞鍵按下 F1 鍵的所有變化。 當使用者按下包含任何鍵盤修飾詞的任何 F1 變化時，類別 Help 會顯示類似 ToolTip 控制項附近的快顯視窗。 如果使用者按下 ALT+F2，則會顯示其他資訊顯示不同的 [說明] 快顯視窗。

   // This example demonstrates how to use the KeyDown event with the Help class to display
   // pop-up style help to the user of the application. The example filters for all variations
   // of pressing the F1 key with a modifier key by using the KeyEventArgs properties passed
   // to the event handling method.
   // When the user presses any variation of F1 that includes any keyboard modifier, the Help
   // class displays a pop-up window, similar to a ToolTip, near the control. If the user presses
   // ALT + F2, a different Help pop-up is displayed with additional information. This example assumes
   // that a tTextBox control, named textBox1, has been added to the form and its KeyDown
   // event has been contected to this event handling method.
private:
   void textBox1_KeyDown( Object^ /*sender*/, System::Windows::Forms::KeyEventArgs^ e )
   {
      // Determine whether the key entered is the F1 key. If it is, display Help.
      if ( e->KeyCode == Keys::F1 && (e->Alt || e->Control || e->Shift) )
      {
         
         // Display a pop-up Help topic to assist the user.
         Help::ShowPopup( textBox1, "Enter your name.", Point(textBox1->Bottom,textBox1->Right) );
      }
      else
      if ( e->KeyCode == Keys::F2 && e->Modifiers == Keys::Alt )
      {
         // Display a pop-up Help topic to provide additional assistance to the user.
         Help::ShowPopup( textBox1, "Enter your first name followed by your last name. Middle name is optional.",
            Point(textBox1->Top,this->textBox1->Left) );
      }
   }

private void textBox1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
    // Determine whether the key entered is the F1 key. If it is, display Help.
    if(e.KeyCode == Keys.F1 && (e.Alt || e.Control || e.Shift))
    {
        // Display a pop-up Help topic to assist the user.
        Help.ShowPopup(textBox1, "Enter your name.", new Point(textBox1.Bottom, textBox1.Right));
    }
    else if(e.KeyCode == Keys.F2 && e.Modifiers == Keys.Alt)
    {
        // Display a pop-up Help topic to provide additional assistance to the user.
        Help.ShowPopup(textBox1, "Enter your first name followed by your last name. Middle name is optional.",
            new Point(textBox1.Top, this.textBox1.Left));
    }
}

Private Sub textBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles textBox1.KeyDown
    ' Determine whether the key entered is the F1 key. If it is, display Help.
    If e.KeyCode = Keys.F1 AndAlso (e.Alt OrElse e.Control OrElse e.Shift) Then
        ' Display a pop-up Help topic to assist the user.
        Help.ShowPopup(textBox1, "Enter your name.", New Point(textBox1.Bottom, textBox1.Right))
    ElseIf e.KeyCode = Keys.F2 AndAlso e.Modifiers = Keys.Alt Then
        ' Display a pop-up Help topic to provide additional assistance to the user.
        Help.ShowPopup(textBox1, "Enter your first name followed by your last name. Middle name is optional.", _
             New Point(textBox1.Top, Me.textBox1.Left))
    End If
End Sub

範例 2

下列範例會判斷使用者是否按下 ALT+E，以及滑鼠指標是否在 上方 TreeNode ，允許使用者編輯該 TreeNode 。

private:
   void treeView1_KeyDown( Object^ /*sender*/, KeyEventArgs^ e )
   {
      /* If the 'Alt' and 'E' keys are pressed,
         * allow the user to edit the TreeNode label. */
      if ( e->Alt && e->KeyCode == Keys::E )
      {
         treeView1->LabelEdit = true;
         
         // If there is a TreeNode under the mouse cursor, begin editing.
         TreeNode^ editNode = treeView1->GetNodeAt( treeView1->PointToClient( Control::MousePosition ) );
         if ( editNode != nullptr )
         {
            editNode->BeginEdit();
         }
      }
   }

   void treeView1_AfterLabelEdit( Object^ /*sender*/, NodeLabelEditEventArgs^ /*e*/ )
   {
      // Disable the ability to edit the TreeNode labels.
      treeView1->LabelEdit = false;
   }

private void treeView1_KeyDown(object sender, KeyEventArgs e)
{
   /* If the 'Alt' and 'E' keys are pressed,
      * allow the user to edit the TreeNode label. */
   if(e.Alt && e.KeyCode == Keys.E)
         
   {
      treeView1.LabelEdit = true;
      // If there is a TreeNode under the mouse cursor, begin editing. 
      TreeNode editNode = treeView1.GetNodeAt(
         treeView1.PointToClient(System.Windows.Forms.Control.MousePosition));
      if(editNode != null)
      { 
         editNode.BeginEdit();
      }
   }
}

private void treeView1_AfterLabelEdit(object sender, NodeLabelEditEventArgs e)
{
   // Disable the ability to edit the TreeNode labels.
   treeView1.LabelEdit = false;
}

Private Sub treeView1_KeyDown(sender As Object, _
  e As KeyEventArgs) Handles treeView1.KeyDown
   ' If the 'Alt' and 'E' keys are pressed,
   ' allow the user to edit the TreeNode label. 
   If e.Alt And e.KeyCode = Keys.E Then
      treeView1.LabelEdit = True
      ' If there is a TreeNode under the mouse cursor, begin editing. 
      Dim editNode As TreeNode = treeView1.GetNodeAt( _
        treeView1.PointToClient(System.Windows.Forms.Control.MousePosition))
      If (editNode IsNot Nothing) Then
         editNode.BeginEdit()
      End If
   End If
End Sub

Private Sub treeView1_AfterLabelEdit(sender As Object, _
  e As NodeLabelEditEventArgs) Handles treeView1.AfterLabelEdit
   ' Disable the ability to edit the TreeNode labels.
   treeView1.LabelEdit = False
End Sub

另請參閱

• Control
• Shift
• Modifiers