圖片檢視(課本第七章實例演練)

PictureBox元件 *1, Button元件*4

程式檔案 圖片檔案

程式碼

Public Class Form1

    Dim no As Integer ' 宣告全域變數以便讓所有事件共用，用來代表第幾張照片
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load PictureBox1.SizeMode = PictureBoxSizeMode.Zoom
       no = 1 '預設為第1張
       PictureBox1.Image = Image.FromFile("相片" & CStr(no) & ".jpg") ' 使用FromFile方法由目前資料夾讀取指定的圖檔
    End Sub

'按第一張鈕顯示第1張相片
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
       no = 1 '設為第1張，使用CStr函式將數值轉成字串
       PictureBox1.Image = Image.FromFile("相片" & CStr(no) & ".jpg")
   End Sub

'按下一張鈕顯示第no+1張相片
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
       no += 1
       If no = 5 Then no = 1 ' 若no等於5，即從令no等於1，即表示再由第一張開始顯示
       PictureBox1.Image = Image.FromFile("相片" & CStr(no) & ".jpg")
    End Sub

'按最後一張鈕顯示第4張相片
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
       no = 4 '設為最後一張(第4張)
       PictureBox1.Image = Image.FromFile("相片" & CStr(no) & ".jpg")
    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
       End
    End Sub
End Class