showvalidate.aspx.vb

《ASP.NET C#程序设计案例教程》

Imports System
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Drawing
Imports System.Drawing.Imaging

Public Class showvalidate: Inherits Page
	Sub Page_Load(Sender As Object,E as Eventargs)
		'这里随机生成一个1000到9999之间的整数,并将其转化为字符串,然后将其保存在Session中
		Dim numTemp As String
		Dim rnd As New Random										'定义一个随机数对象
		numTemp=rnd.Next(1000,9999).ToString						'生成随机数并转化成字符串
		Session("numValidate")=numTemp								'保存到Session中
		'下面建立一个图像，并在上面写字
		Dim bmp As New Bitmap(50,20,PixelFormat.Format32bppArgb)	'建立Bitmap对象
		Dim grh As Graphics = Graphics.FromImage(bmp)				'建立Graphics对象	
		grh.Clear(Color.Gray)										'填充灰色背景
		grh.DrawString(numTemp,new Font("宋体",14),Brushes.Blue,0,0)	'在图像上写字
		'将生成图片以Jpeg格式显示在页面上
		bmp.Save(Response.OutputStream,ImageFormat.Jpeg)
	End Sub
End Class