如何讓Form變型及漸漸淡出及透明

常常看到有些設計師發問如何讓Form展現漸漸淡出或如Vista一樣的透明方式，在這裡本人舉出用程式的方式及圖片的配合做出讓Form產生變型及漸漸淡出及透明。

而本人用了vb6.0及vb.net的方式來表現此方法，讓有心設計美美Form的設計師參考。

在vb6.0裡不需準備一張透明的背景圖，可以用windows裡的API來做，程式碼如下：

Private Declare Function SetWindowPos Lib "user32" (ByVal hWnd As Long, ByVal hWndInsertAfter As Long, ByVal X As Long, Y, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long) As Long

Private Declare Function CreateRoundRectRgn Lib "gdi32" (ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long, ByVal X3 As Long, ByVal Y3 As Long) As Long

Private Declare Function SetWindowRgn Lib "user32" (ByVal hWnd As Long, ByVal hRgn As Long, ByVal bRedraw As Boolean) As Long

Private Declare Function RoundRect Lib "gdi32" (ByVal hDC As Long, ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long, ByVal X3 As Long, ByVal Y3 As Long) As Long

Private Declare Function SetLayeredWindowAttributes Lib "user32" (ByVal hWnd As Long, ByVal crKey As Long, ByVal bAlpha As Byte, ByVal dwFlags As Long) As Long

Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

Const GWL_EXSTYLE = (-20)

Const WS_EX_LAYERED = &H80000

Const LWA_ALPHA = &H2

Const HWND_TOPMOST = -1

Const HWND_NOTOPMOST = -2

Const SWP_NOMOVE = &H2

Const SWP_NOSIZE = &H1

Const TOPMOST_FLAGS = SWP_NOMOVE Or SWP_NOSIZE

Private Sub TOPFORM(hWnd As Long, Action As Boolean)

    If Action = True Then

        SetWindowPos hWnd, HWND_TOPMOST, 0, 0, 0, 0, TOPMOST_FLAGS

    Else

        SetWindowPos hWnd, HWND_NOTOPMOST, 0, 0, 0, 0, TOPMOST_FLAGS

    End If

End Sub

Private Sub Form_Load()

    On Local Error Resume Next

    LBLB.Left = Me.ScaleWidth / 2 - LBLB.Width / 2 - 1

    LBLB.Top = 100

    lonRect = CreateRoundRectRgn(0, 0, Me.ScaleWidth, Me.ScaleHeight, 20, 20)

    SetWindowRgn Me.hWnd, lonRect, True

'    RoundRectBorder Me, 0, 0, Me.ScaleWidth - 1, Me.ScaleHeight - 1, 20, 20, vbWhite

    FormFadeIn Me, 0, 240, 4

    End Sub

Private Sub RoundRectBorder(nObject As Object, X1 As Long, Y1 As Long, X2 As Long, Y2 As Long, X3 As Long, Y3 As Long, nColor As ColorConstants)

    Dim A As Variant

    A = nObject.ForeColor

    nObject.ForeColor = nColor

    RoundRect nObject.hDC, X1, Y1, X2, Y2, X3, Y3

    nObject.ForeColor = A

End Sub

Private Sub FormFadeIn(ByRef nForm As Form, Optional ByVal nFadeStart As Byte = 0, Optional ByVal nFadeEnd As Byte = 255, Optional ByVal nFadeInSpeed As Byte = 5)

    Dim c

    Dim ne As Integer, en(32767) As Boolean

    For Each c In nForm.Controls

        ne = ne + 1

        en(ne) = c.Enabled

        c.Enabled = False

    Next

    If nFadeEnd = 0 Then

        nFadeEnd = 255

    End If

    If nFadeInSpeed = 0 Then

        nFadeInSpeed = 5

    End If

    If nFadeStart >= nFadeEnd Then

        nFadeStart = 0

    ElseIf nFadeEnd <= nFadeStart Then

        nFadeEnd = 255

    End If

    TransparentsForm nForm.hWnd, 0

    nForm.Show

    Dim i As Long

    For i = nFadeStart To nFadeEnd Step nFadeInSpeed

        TransparentsForm nForm.hWnd, CByte(i)

        DoEvents

        Call Sleep(5)

    Next

    TransparentsForm nForm.hWnd, nFadeEnd

    i = 0

    For Each c In nForm.Controls

        i = i + 1

        c.Enabled = en(i)

    Next

End Sub

Private Function TransparentsForm(FormhWnd As Long, Alpha As Byte) As Boolean

    SetWindowLong FormhWnd, GWL_EXSTYLE, WS_EX_LAYERED

    SetLayeredWindowAttributes FormhWnd, 0, Alpha, LWA_ALPHA

    LastAlpha = Alpha

End Function

Private Sub FormFadeOut(ByRef nForm As Form)

    On Local Error Resume Next

    Dim c

    Dim S As Integer

    For Each c In nForm.Controls

        c.Enabled = False

    Next

    Dim i As Long

    For i = 240 To 0 Step -5

        TransparentsForm nForm.hWnd, CByte(i)

        DoEvents

        Call Sleep(5)

    Next

End Sub

'Private Sub SBtn_Exit_Click()

    FormFadeOut Me

    TOPFORM Me.hWnd, False

    Unload Me

End Sub

在vb.net裡我們可以透過一張透明的圖片來達成使Form變行與透明，而方法很簡單，只要在load及paint裡設計程式就可以了。步驟如下：

第一、  在Form的屬性backcolor設定為黑色。

第二、  將Form的windowstate設為normal。

第三、  拉一個picturebox在Form裡。將picturebox的backgroundimage設定準備好的透明圖片。

程式碼如下：

 

Imports System

Imports System.Drawing

Imports System.Drawing.Drawing2D

Imports System.Collections

Imports System.ComponentModel

Imports System.Windows.Forms

Imports System.Data

Imports System.IO

Imports System.Xml.Serialization

Private Sub MainPage_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Me.Location = New System.Drawing.Point(200, 100)

        Me.Opacity = 0

        Me.TransparencyKey = BackColor

    End Sub

    Private Sub MainPage_Paint(ByVal sender As Object, ByVal e As PaintEventArgs) Handles MyBase.Paint

        For dblLoop As System.Double = 0.01 To 1 Step 0.01

            Opacity = dblLoop

            Application.DoEvents()

            Threading.Thread.Sleep(12)

        Next

    End Sub

Private Sub Btn_Exit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btn_Exit.Click

       If MessageBox.Show("確定要離開監測系統嗎?", "離開?", _

                                   MessageBoxButtons.YesNo, MessageBoxIcon.Question, _

                                   MessageBoxDefaultButton.Button1) = DialogResult.Yes Then

            For dblLoop As System.Double = 1 To 0 Step -0.01

                Opacity = dblLoop

                Application.DoEvents()

                Threading.Thread.Sleep(12)

            Next

            Me.Close()

        End If

    End Sub