Control.OnDoubleClick Method (EventArgs)
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Raises the DoubleClick event.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
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(); 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."); } }
Available since 1.1