Control.OnDoubleClick メソッド

.NET Framework クラス ライブラリ リファレンス

Control.OnDoubleClick メソッド

DoubleClick イベントを発生させます。

名前空間: System.Windows.Forms
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文

Visual Basic (宣言)

Protected Overridable Sub
 OnDoubleClick ( _
    e As EventArgs _
)

Visual Basic (使用法)

Dim e As EventArgs

Me.OnDoubleClick(e)

C#

protected virtual void OnDoubleClick (
    EventArgs e
)

C++

protected:
virtual void OnDoubleClick (
    EventArgs^ e
)

J#

protected void OnDoubleClick (
    EventArgs e
)

JScript

protected function OnDoubleClick (
    e : EventArgs
)

パラメータ

e

イベント データを格納している EventArgs。

解説

イベントが発生すると、デリゲートを使用してイベント ハンドラが呼び出されます。詳細については、「イベントの発生」を参照してください。

OnDoubleClick メソッドを使用すると、デリゲートを結び付けずに、派生クラスでイベントを処理することもできます。派生クラスでイベントを処理する場合は、この手法をお勧めします。

継承時の注意 派生クラスで OnDoubleClick をオーバーライドする場合は、登録されているデリゲートがイベントを受け取ることができるように、基本クラスの OnDoubleClick メソッドを呼び出してください。

使用例

ListBox の DoubleClick イベントを使用して、ListBox に示すテキスト ファイルを TextBox コントロールに読み込むコード例を次に示します。

Visual Basic

' 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

C#

// 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.");
    }
}

C++

   // 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." );
      }
   }

J#

// 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.get_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.
                get_SelectedItem().ToString());
            System.IO.TextReader myData = myFile.OpenText();
            textBox1.set_Text(myData.ReadToEnd());
            myData.Close();
        }
    }
    // Exception is thrown by the OpenText method of the FileInfo class.
    catch (System.IO.FileNotFoundException exp) {
        MessageBox.Show("The file you specified does not exist.");
    }
    // Exception is thrown by the ReadToEnd method of the TextReader
 class.
    catch (System.IO.IOException exp) {
        MessageBox.Show("There was a problem loading the file into the "
            + "TextBox. Ensure that the file is a valid text file.");
    }
} //listBox1_DoubleClick

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0

参照

関連項目
Control クラス
Control メンバ
System.Windows.Forms 名前空間
DoubleClick