Export (0) Print
Expand All

Control.OnDoubleClick Method

Raises the DoubleClick event.

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

protected virtual void OnDoubleClick(
	EventArgs 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 void listBox1_DoubleClick(object sender, System.EventArgs e)
    // Get the name of the file to open from the ListBox.
    String file = listBox1.SelectedItem.ToString();

        // 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();
        // Exception is thrown by the OpenText method of the FileInfo class. 
        MessageBox.Show("The file you specified does not exist.");
        // Exception is thrown by the ReadToEnd method of the TextReader class. 
        MessageBox.Show("There was a problem loading the file into the TextBox. Ensure that the file is a valid text file.");

.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
Was this page helpful?
(1500 characters remaining)
Thank you for your feedback
© 2015 Microsoft