Control.DoubleClick Control.DoubleClick Control.DoubleClick Control.DoubleClick Event

Definizione

Si verifica quando si fa doppio clic sul controllo.Occurs when the control is double-clicked.

public:
 event EventHandler ^ DoubleClick;
public event EventHandler DoubleClick;
member this.DoubleClick : EventHandler 
Public Custom Event DoubleClick As EventHandler 

Esempi

Il codice seguente viene illustrato come utilizzare il DoubleClick eventi di un ListBox per caricare i file di testo elencati nella ListBox in un TextBox controllo.The following code example uses the DoubleClick event of a ListBox to load text files listed in the ListBox into a TextBox control.

   // This example uses the DoubleClick event of a ListBox to load text files
   // listed in the ListBox into a TextBox control. This example
   // assumes that the ListBox, named listBox1, contains a list of valid file
   // names with path and that this event handler method
   // is connected to the DoublClick event of a ListBox control named listBox1.
   // This example requires code access permission to access files.
private:
   void listBox1_DoubleClick( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Get the name of the file to open from the ListBox.
      String^ file = listBox1->SelectedItem->ToString();
      try
      {
         // Determine if the file exists before loading.
         if ( System::IO::File::Exists( file ) )
         {
            
            // Open the file and use a TextReader to read the contents into the TextBox.
            System::IO::FileInfo^ myFile = gcnew System::IO::FileInfo( listBox1->SelectedItem->ToString() );
            System::IO::TextReader^ myData = myFile->OpenText();
            ;
            textBox1->Text = myData->ReadToEnd();
            myData->Close();
         }
      }
      // Exception is thrown by the OpenText method of the FileInfo class.
      catch ( System::IO::FileNotFoundException^ ) 
      {
         MessageBox::Show( "The file you specified does not exist." );
      }
      // Exception is thrown by the ReadToEnd method of the TextReader class.
      catch ( System::IO::IOException^ ) 
      {
         MessageBox::Show( "There was a problem loading the file into the TextBox. Ensure that the file is a valid text file." );
      }
   }
// This example uses the DoubleClick event of a ListBox to load text files
// listed in the ListBox into a TextBox control. This example
// assumes that the ListBox, named listBox1, contains a list of valid file
// names with path and that this event handler method
// is connected to the DoublClick event of a ListBox control named listBox1.
// This example requires code access permission to access files.
private void listBox1_DoubleClick(object sender, System.EventArgs e)
{
    // Get the name of the file to open from the ListBox.
    String file = listBox1.SelectedItem.ToString();

    try
    {
        // Determine if the file exists before loading.
        if (System.IO.File.Exists(file))
        {
            // Open the file and use a TextReader to read the contents into the TextBox.
            System.IO.FileInfo myFile = new System.IO.FileInfo(listBox1.SelectedItem.ToString());
            System.IO.TextReader myData = myFile.OpenText();;

            textBox1.Text = myData.ReadToEnd();
            myData.Close();
        }
    }
        // Exception is thrown by the OpenText method of the FileInfo class.
    catch(System.IO.FileNotFoundException)
    {
        MessageBox.Show("The file you specified does not exist.");
    }
        // Exception is thrown by the ReadToEnd method of the TextReader class.
    catch(System.IO.IOException)
    {
        MessageBox.Show("There was a problem loading the file into the TextBox. Ensure that the file is a valid text file.");
    }
}
' This example uses the DoubleClick event of a ListBox to load text files  
' listed in the ListBox into a TextBox control. This example
' assumes that the ListBox, named listBox1, contains a list of valid file 
' names with path and that this event handler method
' is connected to the DoublClick event of a ListBox control named listBox1.
' This example requires code access permission to access files.
Private Sub listBox1_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles listBox1.DoubleClick
    ' Get the name of the file to open from the ListBox.
    Dim file As [String] = listBox1.SelectedItem.ToString()

    Try
        ' Determine if the file exists before loading.
        If System.IO.File.Exists(file) Then
            ' Open the file and use a TextReader to read the contents into the TextBox.
            Dim myFile As New System.IO.FileInfo(listBox1.SelectedItem.ToString())
            Dim myData As System.IO.TextReader = myFile.OpenText()

            textBox1.Text = myData.ReadToEnd()
            myData.Close()
        End If
        ' Exception is thrown by the OpenText method of the FileInfo class.
    Catch
        MessageBox.Show("The file you specified does not exist.")
        ' Exception is thrown by the ReadToEnd method of the TextReader class.
    Catch
     MessageBox.Show("There was a problem loading the file into the TextBox. Ensure that the file is a valid text file.")
    End Try
End Sub

Commenti

Un doppio clic è determinato dalle impostazioni del mouse del sistema operativo dell'utente.A double-click is determined by the mouse settings of the user's operating system. L'utente può impostare un intervallo tra i clic effettuati con un pulsante del mouse in modo che debbano essere considerati come un doppio clic anziché come due clic distinti.The user can set the time between clicks of a mouse button that should be considered a double-click rather than two clicks. Il Click evento viene generato ogni volta che un controllo viene fatto doppio clic.The Click event is raised every time a control is double-clicked. Ad esempio, se si dispongono di gestori eventi per il Click e DoubleClick eventi di un Form, il Click e DoubleClick eventi vengono generati quando il form fare doppio clic ed entrambi i metodi vengono chiamati.For example, if you have event handlers for the Click and DoubleClick events of a Form, the Click and DoubleClick events are raised when the form is double-clicked and both methods are called. Se un controllo è fatto doppio clic e che non supporta il DoubleClick evento, il Click evento potrebbe essere generato due volte.If a control is double-clicked and that control does not support the DoubleClick event, the Click event might be raised twice.

È necessario impostare il StandardDoubleClick e StandardClick i valori di ControlStyles a true per questo evento da generare.You must set the StandardDoubleClick and StandardClick values of ControlStyles to true for this event to be raised. Questi valori potrebbero già essere impostati su true se sta ereditando da esistente controlli Windows Form.These values might already be set to true if you are inheriting from existing Windows Forms controls.

Nota

Gli eventi seguenti non vengono generati per il TabControl classe a meno che non è presente almeno un TabPage nel TabControl.TabPages insieme: Click, DoubleClick, MouseDown, MouseUp, MouseHover, MouseEnter, MouseLeave e MouseMove.The following events are not raised for the TabControl class unless there is at least one TabPage in the TabControl.TabPages collection: Click, DoubleClick, MouseDown, MouseUp, MouseHover, MouseEnter, MouseLeave and MouseMove. Se è presente almeno un TabPage nella raccolta, e l'utente interagisce con l'intestazione del controllo scheda (in cui la TabPage vengono visualizzati i nomi), il TabControl genera l'evento appropriato.If there is at least one TabPage in the collection, and the user interacts with the tab control's header (where the TabPage names appear), the TabControl raises the appropriate event. Tuttavia, se l'interazione dell'utente è all'interno dell'area client della pagina della scheda, il TabPage genera l'evento appropriato.However, if the user interaction is within the client area of the tab page, the TabPage raises the appropriate event.

Per ulteriori informazioni sulla gestione degli eventi, consultare gestione e generazione di eventi.For more information about handling events, see Handling and Raising Events.

Note per gli eredi

Eredità da un controllo standard di Windows Form e modificando il StandardClick o StandardDoubleClick i valori di ControlStyles a true può causare un comportamento imprevisto o del tutto non hanno alcun effetto se il controllo non supporta il Click o DoubleClickgli eventi.Inheriting from a standard Windows Forms control and changing the StandardClick or StandardDoubleClick values of ControlStyles to true can cause unexpected behavior or have no effect at all if the control does not support the Click or DoubleClick events.

La tabella seguente elenca i controlli Windows Form e gli eventi (Click o DoubleClick) viene generata in risposta all'azione del mouse specificato.The following table lists Windows Forms controls and which event (Click or DoubleClick) is raised in response to the mouse action specified.

ControlControl Clic del Mouse a sinistraLeft Mouse Click Fare doppio clic del Mouse a sinistraLeft Mouse Double Click Fare clic destro del MouseRight Mouse Click Fare doppio clic destro del MouseRight Mouse Double Click Fare clic su centrale del Mouse.Middle Mouse Click Fare doppio clic del Mouse al centroMiddle Mouse Double Click Fare clic di pulsante XButton1 del MouseXButton1 Mouse Click Fare doppio clic di pulsante XButton1 del MouseXButton1 Mouse Double-Click Fare clic su di XButton2 del MouseXButton2 Mouse Click Fare doppio clic su di XButton2 del MouseXButton2 Mouse Double-Click
MonthCalendar,MonthCalendar, DateTimePicker,DateTimePicker, RichTextBox,RichTextBox, HScrollBar,HScrollBar, VScrollBar nonenone nonenone nonenone nonenone nonenone nonenone nonenone nonenone nonenone nonenone
Button,Button, CheckBox,CheckBox, RadioButton Fare clic suClick Fare clic suClick, Click nonenone nonenone nonenone nonenone nonenone nonenone nonenone nonenone
ListBox,ListBox, CheckedListBox,CheckedListBox, ComboBox Fare clic suClick Click, DoubleClickClick, DoubleClick nonenone nonenone nonenone nonenone nonenone nonenone nonenone nonenone
TextBox,TextBox, DomainUpDown,DomainUpDown, NumericUpDown Fare clic suClick Click, DoubleClickClick, DoubleClick nonenone nonenone nonenone nonenone nonenone nonenone nonenone nonenone
\* TreeView,\* TreeView, \* ListView\* ListView Fare clic suClick Click, DoubleClickClick, DoubleClick Fare clic suClick Click, DoubleClickClick, DoubleClick nonenone nonenone nonenone nonenone nonenone nonenone
ProgressBar,ProgressBar, TrackBar Fare clic suClick Fare clic suClick, Click Fare clic suClick Fare clic suClick, Click Fare clic suClick Fare clic suClick, Click Fare clic suClick Fare clic suClick, Click Fare clic suClick Fare clic suClick, Click
Form,Form, DataGrid,DataGrid, Label,Label, LinkLabel,LinkLabel, Panel,Panel, GroupBox,GroupBox, PictureBox,PictureBox, Splitter,Splitter, StatusBar,StatusBar, ToolBar,ToolBar, TabPage,TabPage, ** TabControl Fare clic suClick Click, DoubleClickClick, DoubleClick Fare clic suClick Click, DoubleClickClick, DoubleClick Fare clic suClick Click, DoubleClickClick, DoubleClick Fare clic suClick Click, DoubleClickClick, DoubleClick Fare clic suClick Click, DoubleClickClick, DoubleClick

* Il puntatore del mouse deve essere posizionato su un oggetto figlio (TreeNode o ListViewItem).* The mouse pointer must be over a child object (TreeNode or ListViewItem).

* Il TabControl deve avere almeno un TabPage nel relativo TabPages raccolta.** The TabControl must have at least one TabPage in its TabPages collection.

Si applica a

Vedi anche