vb.net校验和 vbnet byval

VB.NET如何对输入的数据进行合法性检验,过滤不合法的数据代码

合法性校验有很多方法，要视情况而定，比如说可以用正则表达式，如果是数字，除了正则表达式，也可以用诸如TryParse这种方法。

10年积累的成都做网站、网站设计经验，可以快速应对客户对网站的新想法和需求。提供各种问题对应的解决方案。让选择我们的客户得到更好、更有力的网络服务。我虽然不认识你，你也不认识我。但先做网站设计后付款的网站建设流程，更有定海免费网站建设让你可以放心的选择与我们合作。

vb.net 点击一个叫button1的按钮 用COM1发送（接收） 假设八位数据位，有奇偶校验位

这是我的简单串口代码：

Dim a As Integer

Dim b As Variant

Private Sub u_Click()

Text1.Text = "请先设置波特率与COM口！！！"

End Sub

Private Sub Cbo1_Click()

On Error GoTo blak '打开串口发生错误，提示信息

If MSComm1.PortOpen = True And a = 1 Then

MSComm1.PortOpen = False '必须先关闭端口，再对端口进行设置

MSComm1.CommPort = cbo1.ListIndex + 1 '端口号从0开始，必须加1

Else '有必要

MSComm1.CommPort = cbo1.ListIndex + 1

End If '注释的必须有，为第二次切换做准备，否则第二次换COM口会出问题

Exit Sub

blak:

MsgBox "串口不存在或被占用!", vbOKOnly, "提示信息" '必须是这种格式

End Sub

Private Sub Cbo2_Click() '单击事件，不是change事件

MSComm1.Settings = 1200 * 2 ^ cbo2.ListIndex "n,8,1" '设置端口的波特率，连接符前后必须空一格

End Sub

Private Sub cmd1_Click()

a = a + 1

If a = 1 Then

cmd1.Caption = "关闭串口"

cbo1.Enabled = False

MSComm1.PortOpen = True '打开串口

ElseIf a = 2 Then

cmd1.Caption = "打开串口"

cbo1.Enabled = True

MSComm1.PortOpen = False '关闭串口

a = 0

End If

End Sub

Private Sub cmd2_Click()

Text1.Text = "" '清空接收区

Text2.SetFocus

End Sub

Private Sub cmd3_Click()

Text2.Text = "" '清空发送区

Text2.SetFocus

End Sub

Private Sub cmd4_Click()

Dim d As Integer

Dim e(0) As Byte 'outbyte 输出字符

d = Val(Text2.Text)

e(0) = CByte(d)

MSComm1.OutBufferCount = 0 '清除发送缓冲区

MSComm1.Output = e '此命令执行一次发送8字节

End Sub

Private Sub Form_Load()

cbo1.ListIndex = 0

cbo2.ListIndex = 0

MSComm1.OutBufferCount = 0

MSComm1.InBufferCount = 0

End Sub

Private Sub MSComm1_OnComm()

Select Case MSComm1.CommEvent '返回最近的通信过程

Case comEvReceive '接受的数据

c: b = MSComm1.Input

If Option1.Value = True Then

Text3.Text = Text1.Text Hex(b(0)) '首次不行，因为有字符

Text1.Text = Text3.Text " " '转换一下

ElseIf Option2.Value = True Then

Text1.Text = Text1.Text b ""

End If

If MSComm1.InBufferCount 0 Then 'mscomm1.InBufferCount是缓冲区的数据数

GoTo c

End If

End Select

End Sub

Private Sub Option1_Click()

MSComm1.InputMode = comInputModeBinary '接收方式，十六进制

End Sub

Private Sub Option2_Click()

MSComm1.InputMode = comInputModeText '接收方式，字符格式

End Sub

Private Sub Text1_Change()

Text1.SelStart = Len(Text1.Text)

End Sub

VB.NET登陆界面。要验证登录用户名和密码是否正确。登陆后有管理员和普通用户权限判断。管理员只能登录一

将用户名，密码，用户类型存在数据库中，登陆时比较输入的值是否与数据库相同即可。

VB.Net 怎么验证 SQL2008 数据库的ID与密码

基础类库：

Imports Microsoft.VisualBasic

'执行Access语句的封装类。

Public Class AccessExecClass

Private conn As Data.OleDb.OleDbConnection

Private cmd As Data.OleDb.OleDbCommand

'创建类对象，并连接到数据库。

Sub New()

If openAccess Then

Else

msgbox("open Access Fail.")

End If

End Sub

'创建类对象，并连接到数据库。 '输入带目录名称的数据库文件名称：dbFileName，例如：“\DB数据库\企业数据库.aspx”

Sub New(ByVal dbFileName As String)

If OpenAccess(dbFileName) Then

Else

MsgBox("open Access Fail.")

End If

End Sub

Function OpenAccess() As Boolean

OpenAccess = False

'检验用户的帐号密码是否正确

Dim provider As String '= ConfigurationManager.ConnectionStrings("ConnectionString").ProviderName

provider = "Provider=Microsoft.Jet.OLEDB.4.0"

Dim database As String

database = "Data Source=" System.Web.HttpContext.Current.Server.MapPath("\数据库.aspx") ";Persist Security Info=true"

conn = New Data.OleDb.OleDbConnection(provider ";" database)

conn.Open()

OpenAccess = True

End Function

Function OpenAccess(ByVal dbFileName As String) As Boolean

OpenAccess = False

'检验用户的帐号密码是否正确

Dim provider As String '= ConfigurationManager.ConnectionStrings("ConnectionString").ProviderName

provider = "Provider=Microsoft.Jet.OLEDB.4.0"

Dim database As String

database = "Data Source=" System.Web.HttpContext.Current.Server.MapPath(dbFileName) ";Persist Security Info=true"

conn = New Data.OleDb.OleDbConnection(provider ";" database)

conn.Open()

OpenAccess = True

End Function

'关闭数据库。

Sub CloseAccess()

cmd = Nothing

conn.Close()

End Sub

'执行一条Access语句，执行成功就返回True。

Function ExecAccessString(ByVal AccessStr As String) As Boolean

cmd = New Data.OleDb.OleDbCommand(AccessStr, conn)

cmd.ExecuteNonQuery()

'Dim aa As Data.OleDb.OleDbDataReader = cmd.ExecuteReader

ExecAccessString = True

End Function

'返回读取到的数据，注意是用地址传递方式返回

Sub ExecAccessString(ByVal AccessStr As String, ByRef AccessReader As Data.OleDb.OleDbDataReader)

cmd = New Data.OleDb.OleDbCommand(AccessStr, conn)

cmd.ExecuteNonQuery()

AccessReader = cmd.ExecuteReader

End Sub

End Class

登陆代码：

Protected Sub LinkButton1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles LinkButton1.Click

Dim wl As New WebLog '用户登录记录开始，仅对购买了Log 功能的用户，才开放此功能，否则不会实际记录Log

Dim sql As String

Dim aDB As New AccessExecClass

Dim mypw As String

Label1.Visible = False

Label2.Visible = False

Label3.Visible = False

Label4.Visible = False

'没有输入时,不能进行登陆

If TextBox1.Text = "" Then

Label1.Visible = True

Return

End If

If TextBox2.Text = "" Then

Label2.Visible = True

Return

End If

If TextBox3.Text = "" Then

Label3.Visible = True

Return

End If

If TextBox3.Text = TextBox4.Text Then

Else

Label3.Visible = True

Return

End If

Dim iRnd As Integer = Rnd(10) * 100

TextBox3.Text = ""

TextBox4.Text = iRnd.ToString

'Dim iRnd As Integer = Rnd(10) * 100

'注意:此处需要加入防止注入分析,包含'的肯定是特别语句,讲拒绝.

If TextBox1.Text.IndexOf("'") 0 Or TextBox2.Text.IndexOf("'") 0 Then

TextBox1.Text = "不能输入非法字符,将强制清空"

TextBox2.Text = ""

Else

Dim pw As New MD5EnCode(13, 19) ' '2次加密

sql = "select 权限组号,ID , 密码 from 编辑人数据 where 编辑姓名='" + TextBox1.Text + "'"

Dim aa As Data.OleDb.OleDbDataReader '= cmd.ExecuteReader

aDB.ExecAccessString(sql, aa)

If aa.Read() Then

'密码正确()

'sql = aa(2)'需要特别注意：只能单向解密，不能直接转换

mypw = pw.simDeCode(pw.simDeCode(aa(2)))

If TextBox2.Text = mypw Then

Session("LOGIN_Name") = TextBox1.Text '设置登录后的用户名称

Session("Login_Group") = aa(0) 'cmd.ExecuteScalar '设置登录后的权限级别

Session("Login_ID") = aa(1) 'cmd.ToString

'cmd = Nothing

'conn.Close()

Call wl.NewLog("登录", "管理员成功登录")

Response.Redirect("../WebManages/Default.ASPX")

Else

'密码错误()

sql = sql.Replace("'", "【单引号】")

sql = sql.Replace(",", "【逗号】")

Call wl.NewLog("登录", "管理员失败的登录", TextBox1.Text, sql.Replace("""", "【双引号】"), "")

Label4.Visible = True

End If

Else

'密码错误()

sql = sql.Replace("'", "【单引号】")

sql = sql.Replace(",", "【逗号】")

Call wl.NewLog("登录", "管理员失败的登录", TextBox1.Text, sql.Replace("""", "【双引号】"), "")

Label4.Visible = True

End If

End If

End Sub