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首页 - 经验之谈 - 使机箱内的小喇叭发出不同的声音
发表评论(0)作者:, 平台:, 阅读:15002, 日期:2000-03-12

- chengdx


Mmsound.drv 是小喇叭的系统接口 ,很多API的书都有用法介绍

- 219 张晶




Use the Beep API function.

This example demonstrates two interesting things. First, it shows how to

make a beep of any frequency and duration rather than using the standard

tone you get with the Beep statement.

Second, note that the Beep API function has the same name as Visual

Basic's Beep statement. To differentiate them, you can assign a new name

to the Beep API function in its Declare statement. It is known as "Beep"

in the library (the Alias statement) but it is known as APIBeep to the


You can use this technique to differentiate between functions with the

same name, or you can use it to give API functions a name that is easier

to write (for example, if the API name is very long).

In the declarations section:

Option Explicit

Private Declare Function APIBeep Lib "kernel32" Alias "Beep" ( _

ByVal dwFreq As Long, ByVal dwDuration As Long) As Long

To make a beep lasting 500 milliseconds with frequency specified in the

TextBox txtFrequency (try 1000 for starters):

Private Sub Command1_Click()

Dim frequency As Long

frequency = CLng(txtFrequency.Text)

APIBeep frequency, 500

End Sub

- Prisoner