Button

   PostBack Using Button
   Bubbling Button Clicks Within a List
   Mouse-Over Effects on Button

Bubbling Button Clicks Within a List

When used in a templated list such as a Repeater, DataList, or DataGrid, many Button controls might be rendered as the list iterates over its data source. For more information, see the Data Binding section. Because each of these Button controls shares the same ID, you cannot simply bind an event handler to each Button control's OnClick event to determine the particular Button that was clicked. To solve this, you use event bubbling to fire an event on the container control (in this case, the Repeater, DataList, or DataGrid), and let the container impart additional information to the event handler about the item that fired the event.

These events can be fired from a Button by specifying a CommandName property with the name of the event. When the Button is clicked, the command "bubbles" to the container control (such as Repeater), which fires its own event. The arguments for this event might contain additional information, such as a custom string or the index of the item that fired the event.

The following sample illustrates how a Button control's commands can bubble to the OnItemCommand event of a list. The Button control's CommandName and CommandArgument strings are passed to the OnItemCommand event, permitting the sample code to distinguish which button was clicked.

VB Button2.aspx [Run Sample] | [View Source]

Mouse-Over Effects on Button

You can hook the client script events onmouseover and onmouseout on a Button control to provide mouse-over effects such as changing the font or color of the button. Client attributes such as onmouseover are disregarded by ASP.NET on the server, and passed "as is" to the browser. If your application targets newer browsers that support DHTML, these events will fire in the browser as the cursor passes over the button. The following sample demonstrates buttons with mouse-over effects.

VB Button3.aspx [Run Sample] | [View Source]