Imports System.Text
Imports System.Runtime.InteropServices

Public Class frmStart

    Private Sub frmStart_Load(sender As Object,e As EventArgs) Handles Me.Load

        Dim bb As Bitmap

        bb = vbnetStartForm.My.Resources.Resources.earch

        Dim bmp As New Bitmap(bb)

        SetBits(bmp)

    End Sub

#Region "窗体移动"
    <DllImport("user32.dll")>
    Public Shared Function ReleaseCapture() As Boolean
    End Function
    <DllImport("user32.dll")>
    Public Shared Function SendMessage(hwnd As IntPtr,wMsg As Integer,wParam As Integer,lParam As Integer) As Boolean
    End Function
    Public Const WM_SYSCOMMAND As Integer = &H112
    Public Const SC_MOVE As Integer = &HF010
    Public Const HTCAPTION As Integer = &H2
    '无边框窗体移动
#End Region

#Region "调用UpdateLayeredWindow函数"

    Protected Overrides ReadOnly Property CreateParams() As CreateParams
        '重载窗体的CreateParams方法
        Get
            Const WS_MINIMIZEBox As Integer = &H20000
            ' Winuser.h中定义
            Dim cp As CreateParams = MyBase.CreateParams
            cp.Style = cp.Style Or WS_MINIMIZEBox
            ' 允许最小化操作
            cp.ExStyle = cp.ExStyle Or &H80000
            ' WS_EX_LAYERED
            Return cp
        End Get
    End Property

    Public Sub SetBits(bitmap__1 As Bitmap)
        '调用UpdateLayeredWindow（）方法。this.BackgroundImage为你事先准备的带透明图片。
        'if (!haveHandle) return;

        If Not Bitmap.IsCanonicalPixelFormat(bitmap__1.PixelFormat) OrElse Not Bitmap.IsAlphaPixelFormat(bitmap__1.PixelFormat) Then
            Throw New ApplicationException("图片必须是32位带Alhpa通道的图片。")
        End If

        Dim oldBits As IntPtr = IntPtr.Zero
        Dim screenDC As IntPtr = Win32.GetDC(IntPtr.Zero)
        Dim hBitmap As IntPtr = IntPtr.Zero
        Dim memDc As IntPtr = Win32.CreateCompatibleDC(screenDC)

        Try
            Dim topLoc As New Win32.Point(Left,Top)
            Dim bitMapSize As New Win32.Size(bitmap__1.Width,bitmap__1.Height)
            Dim blendFunc As New Win32.BLENDFUNCTION()
            Dim srcLoc As New Win32.Point(0,0)

            hBitmap = bitmap__1.GetHbitmap(Color.FromArgb(0))
            oldBits = Win32.SelectObject(memDc,hBitmap)

            blendFunc.BlendOp = Win32.AC_SRC_OVER
            blendFunc.SourceConstantAlpha = 255
            blendFunc.AlphaFormat = Win32.AC_SRC_ALPHA
            blendFunc.BlendFlags = 0

            Win32.UpdateLayeredWindow(Handle,screenDC,topLoc,bitMapSize,memDc,srcLoc,blendFunc,Win32.ULW_ALPHA)
        Finally
            If hBitmap <> IntPtr.Zero Then
                Win32.SelectObject(memDc,oldBits)
                Win32.DeleteObject(hBitmap)
            End If
            Win32.ReleaseDC(IntPtr.Zero,screenDC)
            Win32.DeleteDC(memDc)
        End Try
    End Sub

#End Region

#Region "Win32 API声明"
    Class Win32
        <StructLayout(LayoutKind.Sequential)>
        Public Structure Size
            Public cx As Int32
            Public cy As Int32

            Public Sub New(x As Int32,y As Int32)
                cx = x
                cy = y
            End Sub
        End Structure

        <StructLayout(LayoutKind.Sequential,Pack:=1)>
        Public Structure BLENDFUNCTION
            Public BlendOp As Byte
            Public BlendFlags As Byte
            Public SourceConstantAlpha As Byte
            Public AlphaFormat As Byte
        End Structure

        <StructLayout(LayoutKind.Sequential)>
        Public Structure Point
            Public x As Int32
            Public y As Int32

            Public Sub New(x As Int32,y As Int32)
                Me.x = x
                Me.y = y
            End Sub
        End Structure

        Public Const AC_SRC_OVER As Byte = 0
        Public Const ULW_ALPHA As Int32 = 2
        Public Const AC_SRC_ALPHA As Byte = 1

        Public Declare Auto Function CreateCompatibleDC Lib "gdi32.dll" (hDC As IntPtr) As IntPtr

        Public Declare Auto Function GetDC Lib "user32.dll" (hWnd As IntPtr) As IntPtr

        <DllImport("gdi32.dll",ExactSpelling:=True)>
        Public Shared Function SelectObject(hDC As IntPtr,hObj As IntPtr) As IntPtr
        End Function

        <DllImport("user32.dll",ExactSpelling:=True)>
        Public Shared Function ReleaseDC(hWnd As IntPtr,hDC As IntPtr) As Integer
        End Function

        Public Declare Auto Function DeleteDC Lib "gdi32.dll" (hDC As IntPtr) As Integer

        Public Declare Auto Function DeleteObject Lib "gdi32.dll" (hObj As IntPtr) As Integer

        Public Declare Auto Function UpdateLayeredWindow Lib "user32.dll" (hwnd As IntPtr,hdcDst As IntPtr,ByRef pptDst As Point,ByRef psize As Size,hdcSrc As IntPtr,ByRef pptSrc As Point,crKey As Int32,ByRef pblend As BLENDFUNCTION,dwFlags As Int32) As Integer

        Public Declare Auto Function ExtCreateRegion Lib "gdi32.dll" (lpXform As IntPtr,nCount As UInteger,rgnData As IntPtr) As IntPtr
    End Class
#End Region

    Private Sub frmStart_MouseDown(sender As Object,e As MouseEventArgs) Handles MyBase.MouseDown
        ReleaseCapture()
        SendMessage(Me.Handle,WM_SYSCOMMAND,SC_MOVE + HTCAPTION,0)
        '窗体移动
    End Sub

End Class

文章比较乱请多包涵，下面的地址是我在写文章时测试的项目文件源码，有兴趣的朋友可以下载测试下，有什么问题可留言，我看到后会尽量回复

http://download.csdn.net/detail/ivanwfy/9888101