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Control.OnDoubleClick Method

Raises the DoubleClick event.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

'Declaration
Protected Overridable Sub OnDoubleClick ( _
	e As EventArgs _
)

Parameters

e
Type: System.EventArgs

An EventArgs that contains the event data.

Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.

The OnDoubleClick method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors

When overriding OnDoubleClick in a derived class, be sure to call the base class's OnDoubleClick method so that registered delegates receive the event.

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 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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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