关于一个函数的问题

tomzhang

Begin Dialog dialogName [x , y ,] dx , dy [, caption$ ]  [, .dialogfunction ]

...        ' dialog box definition statements

End Dialog

这是创建一个对话框 的函数,我对最后一个参数不太理解,在help中得到如下:
The optional .dialogfunction function must be defined (using the Function statement) or declared (using Dim) before being used in the Begin Dialog statement. Define the dialogfunction with the following three arguments:

Function dialogfunction% ( id$ , action% , suppvalue& )

...                        ' function body
End Function

Following are the descriptions of the arguments:

Argument        Description

id$        The text string that identifies the dialog control that triggered the call to the dialog function (usually because the user changed this control).

action%        An integer from 1 to 5 identifying the reason why the dialog function was called.

suppvalue&        Gives more specific information about why the dialog function was called.

action%,suppvalue&代表什么？
想知道如何可以引发控件的事件，最好斑竹能给个简单的例子！！