form1.vb

这是一本用Visual Studio.NET进行多媒体编程的读物

Option Strict Off
Option Explicit On
Friend Class Form1
	Inherits System.Windows.Forms.Form
#Region "Windows 窗体设计器生成的代码"
	Public Sub New()
		MyBase.New()
		If m_vb6FormDefInstance Is Nothing Then
			If m_InitializingDefInstance Then
				m_vb6FormDefInstance = Me
			Else
				Try 
					'对于启动窗体，所创建的第一个实例为默认实例。
					If System.Reflection.Assembly.GetExecutingAssembly.EntryPoint.DeclaringType Is Me.GetType Then
						m_vb6FormDefInstance = Me
					End If
				Catch
				End Try
			End If
		End If
		'此调用是 Windows 窗体设计器所必需的。
		InitializeComponent()
	End Sub
	'窗体重写处置，以清理组件列表。
	Protected Overloads Overrides Sub Dispose(ByVal Disposing As Boolean)
		If Disposing Then
			If Not components Is Nothing Then
				components.Dispose()
			End If
		End If
		MyBase.Dispose(Disposing)
	End Sub
    Private components As System.ComponentModel.IContainer
	'Windows 窗体设计器所必需的
		Public ToolTip1 As System.Windows.Forms.ToolTip
	Public WithEvents Command2 As System.Windows.Forms.Button
	Public WithEvents Command1 As System.Windows.Forms.Button
	Public WithEvents HScroll2 As System.Windows.Forms.HScrollBar
	Public WithEvents HScroll1 As System.Windows.Forms.HScrollBar
	Public WithEvents Label2 As System.Windows.Forms.Label
	Public WithEvents Label1 As System.Windows.Forms.Label
	'注意：以下过程是 Windows 窗体设计器所必需的
	'可以使用 Windows 窗体设计器来修改它。
	'不要使用代码编辑器来修改它。
	<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.components = New System.ComponentModel.Container()
        Me.Command1 = New System.Windows.Forms.Button()
        Me.Command2 = New System.Windows.Forms.Button()
        Me.ToolTip1 = New System.Windows.Forms.ToolTip(Me.components)
        Me.HScroll2 = New System.Windows.Forms.HScrollBar()
        Me.HScroll1 = New System.Windows.Forms.HScrollBar()
        Me.Label1 = New System.Windows.Forms.Label()
        Me.Label2 = New System.Windows.Forms.Label()
        Me.SuspendLayout()
        '
        'Command1
        '
        Me.Command1.BackColor = System.Drawing.SystemColors.Control
        Me.Command1.Cursor = System.Windows.Forms.Cursors.Default
        Me.Command1.Location = New System.Drawing.Point(8, 83)
        Me.Command1.Name = "Command1"
        Me.Command1.RightToLeft = System.Windows.Forms.RightToLeft.No
        Me.Command1.Size = New System.Drawing.Size(166, 29)
        Me.Command1.TabIndex = 4
        Me.Command1.Text = "停止播放"
        '
        'Command2
        '
        Me.Command2.BackColor = System.Drawing.SystemColors.Control
        Me.Command2.Cursor = System.Windows.Forms.Cursors.Default
        Me.Command2.Location = New System.Drawing.Point(192, 83)
        Me.Command2.Name = "Command2"
        Me.Command2.RightToLeft = System.Windows.Forms.RightToLeft.No
        Me.Command2.Size = New System.Drawing.Size(175, 29)
        Me.Command2.TabIndex = 5
        Me.Command2.Text = "播放测试声音"
        '
        'HScroll2
        '
        Me.HScroll2.Cursor = System.Windows.Forms.Cursors.Default
        Me.HScroll2.LargeChange = 1
        Me.HScroll2.Location = New System.Drawing.Point(80, 46)
        Me.HScroll2.Maximum = 255
        Me.HScroll2.Name = "HScroll2"
        Me.HScroll2.RightToLeft = System.Windows.Forms.RightToLeft.No
        Me.HScroll2.Size = New System.Drawing.Size(288, 20)
        Me.HScroll2.TabIndex = 2
        Me.HScroll2.TabStop = True
        '
        'HScroll1
        '
        Me.HScroll1.Cursor = System.Windows.Forms.Cursors.Default
        Me.HScroll1.LargeChange = 1
        Me.HScroll1.Location = New System.Drawing.Point(80, 19)
        Me.HScroll1.Maximum = 255
        Me.HScroll1.Name = "HScroll1"
        Me.HScroll1.RightToLeft = System.Windows.Forms.RightToLeft.No
        Me.HScroll1.Size = New System.Drawing.Size(288, 19)
        Me.HScroll1.TabIndex = 0
        Me.HScroll1.TabStop = True
        '
        'Label1
        '
        Me.Label1.BackColor = System.Drawing.SystemColors.Control
        Me.Label1.Cursor = System.Windows.Forms.Cursors.Default
        Me.Label1.ForeColor = System.Drawing.SystemColors.ControlText
        Me.Label1.Location = New System.Drawing.Point(8, 19)
        Me.Label1.Name = "Label1"
        Me.Label1.RightToLeft = System.Windows.Forms.RightToLeft.No
        Me.Label1.Size = New System.Drawing.Size(63, 19)
        Me.Label1.TabIndex = 1
        Me.Label1.Text = "左声道"
        '
        'Label2
        '
        Me.Label2.BackColor = System.Drawing.SystemColors.Control
        Me.Label2.Cursor = System.Windows.Forms.Cursors.Default
        Me.Label2.ForeColor = System.Drawing.SystemColors.ControlText
        Me.Label2.Location = New System.Drawing.Point(8, 46)
        Me.Label2.Name = "Label2"
        Me.Label2.RightToLeft = System.Windows.Forms.RightToLeft.No
        Me.Label2.Size = New System.Drawing.Size(63, 20)
        Me.Label2.TabIndex = 3
        Me.Label2.Text = "右声道"
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
        Me.ClientSize = New System.Drawing.Size(376, 119)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Command2, Me.Command1, Me.HScroll2, Me.HScroll1, Me.Label2, Me.Label1})
        Me.Location = New System.Drawing.Point(3, 16)
        Me.MaximizeBox = False
        Me.MinimizeBox = False
        Me.Name = "Form1"
        Me.StartPosition = System.Windows.Forms.FormStartPosition.Manual
        Me.Text = "控制音量API函数的使用"
        Me.ResumeLayout(False)

    End Sub
#End Region 
#Region "升级支持"
	Private Shared m_vb6FormDefInstance As Form1
	Private Shared m_InitializingDefInstance As Boolean
	Public Shared Property DefInstance() As Form1
		Get
			If m_vb6FormDefInstance Is Nothing OrElse m_vb6FormDefInstance.IsDisposed Then
				m_InitializingDefInstance = True
				m_vb6FormDefInstance = New Form1()
				m_InitializingDefInstance = False
			End If
			DefInstance = m_vb6FormDefInstance
		End Get
		Set
			m_vb6FormDefInstance = Value
		End Set
	End Property
#End Region 
	Private Declare Function waveOutGetVolume Lib "winmm.dll" (ByVal uDeviceID As Integer, ByRef lpdwVolume As Integer) As Integer
	Private Declare Function waveOutSetVolume Lib "winmm.dll" (ByVal uDeviceID As Integer, ByVal dwVolume As Integer) As Integer
	Private Declare Function waveOutGetDevCaps Lib "winmm.dll"  Alias "waveOutGetDevCapsA"(ByVal uDeviceID As Integer, ByRef lpCaps As WAVEOUTCAPS, ByVal uSize As Integer) As Integer
	Private Declare Function sndPlaySound Lib "winmm.dll"  Alias "sndPlaySoundA"(ByVal lpszSoundName As String, ByVal uFlags As Integer) As Integer
	
	Const SND_ASYNC As Short = &H1s
	Const SND_PURGE As Short = &H40s
	Const WAVE_MAPPER As Short = -1
	Const MAXPNAMELEN As Short = 32
	Const MMSYSERR_NOERROR As Short = 0
	
	Private Structure WAVEOUTCAPS
		Dim wMid As Short
		Dim wPid As Short
		Dim vDriverVersion As Integer
		<VBFixedString(MAXPNAMELEN),System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.ByValTStr,SizeConst:=MAXPNAMELEN)> Dim szPname As String
		Dim dwFormats As Integer
		Dim wChannels As Short
		Dim dwSupport As Integer
	End Structure
	Private Sub Form1_Load(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles MyBase.Load
		Dim lVol As Integer
		Dim tWaveCaps As WAVEOUTCAPS
		
		waveOutGetVolume(WAVE_MAPPER, lVol)
		System.Diagnostics.Debug.WriteLine(Hex(lVol))
		HScroll1.Value = (lVol And 255)
		HScroll2.Value = ((lVol \ &H10000) And 255)
	End Sub

    Private Sub HScroll1_Change(ByVal newScrollValue As Integer)
        SetVolume()
    End Sub

    Private Sub HScroll2_Change(ByVal newScrollValue As Integer)
        SetVolume()
    End Sub
    Private Sub Command1_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles Command1.Click
        '停止播放测试声音
        Dim aa As String
        sndPlaySound(aa, SND_ASYNC)
    End Sub

    Private Sub Command2_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles Command2.Click
        '播放播放测试声音
        sndPlaySound("e:\demo1.wav", SND_ASYNC)
    End Sub
    Sub SetVolume()
        Dim lVol As Integer
        lVol = CInt(HScroll2.Value) * &H100S Or HScroll1.Value
        '设置音量
        If waveOutSetVolume(WAVE_MAPPER, lVol) <> MMSYSERR_NOERROR Then
            MsgBox("音量设置出错")
        End If
    End Sub
    Private Sub HScroll1_Scroll(ByVal eventSender As System.Object, ByVal eventArgs As System.Windows.Forms.ScrollEventArgs) Handles HScroll1.Scroll
        Select Case eventArgs.Type
            Case System.Windows.Forms.ScrollEventType.EndScroll
                HScroll1_Change(eventArgs.NewValue)
        End Select
    End Sub
    Private Sub HScroll2_Scroll(ByVal eventSender As System.Object, ByVal eventArgs As System.Windows.Forms.ScrollEventArgs) Handles HScroll2.Scroll
        Select Case eventArgs.Type
            Case System.Windows.Forms.ScrollEventType.EndScroll
                HScroll2_Change(eventArgs.NewValue)
        End Select
    End Sub
End Class