HOW TO: Use the .NET Framework Properties and Events in Visual J# .NET (316680)

SUMMARY

This step-by-step article discusses how to use the Microsoft .NET Framework properties and the .NET Framework predefined events in your Microsoft Visual J# .NET application.

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How to Gain Access to the .NET Framework Properties

Through Visual J# .NET, you cannot gain direct access to the .NET Framework properties and events. However, you can use the get_Property method and the set_Property method in Visual J# .NET to gain access to the .NET Framework properties.

Use get_Property Name to gain access to a .NET Framework property, and then use set_Property Name to set the property. For example, to get the value of the Text property of a button, use the get_Property method as follows:

String buttonText = this.sendButton.get_Text();

To set the value of the Text property of the button, use the set_Property method as follows:

this.sendButton.set_Text("Send");

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How to Define the .NET Framework Predefined Events

Visual J# .NET provides the add_Event method and the remove_Event method to define event handlers for the .NET Framework predefined events. Use the add_Event method to add an event handler for an event. Use the remove_Event method to remove the event handler for that event. For example, to add a Click event handler for a button, use the add_Event method as follows:

this.sendButton.add_Click( new System.EventHandler(this.sendButton_Click) );

To remove a Click event handler for a button, use the remove_Event method as follows:

this.sendButton.remove_Click(new System.EventHandler(this.sendButton_Click));

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Step-by-Step Procedure

1. Start Microsoft Visual Studio .NET.
2. On the File menu, point to New, and then click Project.
3. Under Project Types, click Visual J# Projects, and then click Windows Application under Templates.
4. In the Name text box, type MyJSharpWindowsApplication, and then type C:\ in the Location text box. Click OK.
5. In Design view, drag a Button from the Toolbox to Form1.
6. Double-click Form1, and then paste the following Form_Load event sample code in the button1_Click event:

   MessageBox.Show("Adding an Event Handler for a Button Click Event");
   this.button1.add_Click(new System.EventHandler(this.MyHandler));

7. After the Form1_Load method, paste the following sample code:

   private void MyHandler(Object sender,System.EventArgs e)
   {
   	// Setting Text Property of the Button
   	button1.set_Text("Button Text");
   	// Getting Text Property of Button
   	MessageBox.Show("New Text Property Value of Button1 " + button1.get_Text());
   	MessageBox.Show("Now Removing the Existing Event Handler");
   	// Removing the Event
   	this.button1.remove_Click(new System.EventHandler(this.MyHandler));
   }

8. On the Debug menu, click Start.
9. Click button1. In the Form1_Load event handler, notice that the add_Click method is added to the button. Also, notice that the text on button1 has changed to Button Text.
10. Click button1 again. Notice that the messages do not appear.

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