Control.DoubleClick 活动

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

Source:

Control.cs

双击控件时发生。

public:
 event EventHandler ^ DoubleClick;

public event EventHandler? DoubleClick;

member this.DoubleClick : EventHandler 

Public Custom Event DoubleClick As EventHandler 

事件类型

EventHandler

示例

下面的代码示例使用DoubleClick事件ListBox将列表中列出的文本文件加载到ListBox控件中TextBox。

   // 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

注解

双击由用户的操作系统的鼠标设置决定。 用户可以设置鼠标按钮单击之间的时间，该按钮应被视为双击，而不是两次单击。 Click每次双击控件时都会引发该事件。 例如，如果你有事件的ClickDoubleClickFormClick事件处理程序，则当双击窗体并调用这两种方法时，将引发和DoubleClick事件。 如果双击某个控件并且该控件不支持该 DoubleClick 事件， Click 则可能会引发该事件两次。

必须设置StandardDoubleClick要引发此事件的和StandardClick值ControlStylestrue。 如果从现有Windows 窗体控件继承，这些值可能已设置为 true。

注释

除非集合TabControl中至少有一个：、、TabPage、TabControl.TabPages、ClickDoubleClick、、 MouseDown和MouseUp中MouseHover至少有一个MouseEnter，否则不会为MouseLeave类引发以下MouseMove事件。 如果集合中至少有一个 TabPage ，并且用户与选项卡控件的标头（其中 TabPage 显示名称）交互，则会 TabControl 引发相应的事件。 但是，如果用户交互位于选项卡页的工作区内，则会 TabPage 引发相应的事件。

有关处理事件的详细信息，请参阅 处理和引发事件。

继承者说明

从标准Windows 窗体控件继承并将 StandardClick 或 StandardDoubleClick 值ControlStyles更改为 true可能会导致意外行为，或者如果控件不支持 Click 或 DoubleClick 事件，则根本不起作用。

下表列出了Windows 窗体控件以及为响应指定的鼠标操作而引发的事件（Click或 DoubleClick）。

控制	鼠标左键单击	鼠标左键双击	右键单击	鼠标右键双击	鼠标中键单击	鼠标中间双击	XButton1 鼠标单击	XButton1 鼠标 Double-Click	XButton2 鼠标单击	XButton2 鼠标 Double-Click
MonthCalendar、 DateTimePicker, RichTextBox, HScrollBar, VScrollBar	没有	无	无	无	无	无	无	无	无	无
Button、 CheckBox, RadioButton	单击	单击，单击	无	无	无	无	无	无	无	无
ListBox、 CheckedListBox, ComboBox	单击	单击，DoubleClick	无	无	无	无	无	无	无	无
TextBox、 DomainUpDown, NumericUpDown	单击	单击，DoubleClick	无	无	无	无	无	无	无	无
* TreeView, * ListView	单击	单击，DoubleClick	单击	单击，DoubleClick	无	无	无	无	无	无
ProgressBar、 TrackBar	单击	单击，单击	单击	单击，单击	单击	单击，单击	单击	单击，单击	单击	单击，单击
Form、 DataGrid, Label, LinkLabel, Panel, GroupBox, PictureBox, Splitter, StatusBar, ToolBar, TabPage, ** TabControl	单击	单击，DoubleClick	单击	单击，DoubleClick	单击	单击，DoubleClick	单击	单击，DoubleClick	单击	单击，DoubleClick

* 鼠标指针必须位于子对象上（TreeNode 或 ListViewItem）。

TabControl** 集合TabPage中必须至少有一个TabPages。

另请参阅

• OnDoubleClick(EventArgs)
• StandardClick
• StandardDoubleClick
• Click
• MouseClick
• MouseDoubleClick