用户登录验证程序——VB.NET

Introduction

实现用户登录功能，UI使用WinForm提供LoginForm,然后建一个User表保存用户信息（UserName, PassWrd, UserActive, Comment），使用Linq对User表进行查询。

plainText = CryptographyUtils.Decrypt(CryptographyUtils.CreateSymmAlgoRC2(),cipherText, "JK_huangJK_huang", 128CryptographyUtils.CreateSymmAlgoRC2(),cipherText, "JK_huangJK_huang", 128);

Backgroud

使用Visual studio2008,sql server 2005开发

 

The Definition of User Table

 

 
SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

CREATE TABLE [dbo].[t_UserInfo](

    [UserName] [nvarchar](20) NOT NULL,

    [PassWrd] [nvarchar](20) NOT NULL,

    [UserActive] [bit] NOT NULL,

    [Comment] [nvarchar](50) NULL,

 CONSTRAINT [PK_t_UserInfo] PRIMARY KEY CLUSTERED 

(

    [UserName] ASC

)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]

) ON [PRIMARY]
 

 

 

 

Validing the user and Passing Data to Database

上传数据方法，当CheckReg.Checked = True是创建新用户，False时检验当前用户是否有效

 

 

    Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
        Dim loginDS As New TestInfoDataSet.t_UserInfoDataTable
        Dim loginDA As New TestInfoDataSetTableAdapters.t_UserInfoTableAdapter

        If CheckReg.Checked = True Then
            Try
                loginDA.Insert(comUser.Text.ToString(), txtPW.Text.ToString(), True, "")
            Catch ex As Exception
                MessageBox.Show("The UserName already exist", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)
                comUser.Focus()
                comUser.Text = ""
            Finally
                Me.ClearForm()
            End Try
        Else
            Try
                loginDA.FillByUserData(loginDS, comUser.ToString(), txtPW.ToString())
                Check_Details()
            Catch ex As Exception
                MsgBox("Invalid User Name", MsgBoxStyle.Critical, "Error")
            End Try
        End If

End Sub

 

 

使用Linq查询用户是否存在User表中

 

 

    Private Sub Check_Details()
        Dim PWord As String = Me.txtPW.Text.ToString.Trim

        Dim CheckDA As New TestInfoDataSetTableAdapters.t_UserInfoTableAdapter
        Dim query = From check In CheckDA.GetData _
                    Select check.UserName, check.PassWrd, check.UserActive _
                    Where UserName = UName AndAlso PassWrd = PWord _
                                AndAlso UserActive = True
        If query.Count() = 1 Then
            MessageBox.Show("confirmed", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)
            Me.ClearForm()
        Else
            MessageBox.Show("Password Is Incorrect or no longer Valid", "Incorrect Password", MessageBoxButtons.OK, MessageBoxIcon.Information)
            txtPW.Focus()
            txtPW.Text = ""

        End If

End Sub

 

 

Data Valide

进行输入操作时是全角输入就要转换为半角输入，这里使用两种方法进行全角到半角的转换

 

1.处理输入后的数据2.只输入半角字符

 Private Function ToDBC(ByVal tmpStr As String) As String
        Dim i As Integer = 0

        Dim c() As Char = tmpStr.ToCharArray()
        Dim length As Integer = c.Length - 1

        For i = 0 To length
            If c(i) = "　" Then
                c(i) = CChar(" ")
            ElseIf AscW(c(i)) > 65280 And AscW(c(i)) < 65375 Then
                c(i) = ChrW(AscW(c(i)) - 65248)
            End If
        Next
        Return CStr(c)
    End Function
End Class

 

2.关闭输入法

Me.comUser.ImeMode = Forms.ImeMode.Close ‘直接关闭全角输入

  

https://files.cnblogs.com/rush/登录检验程序.rar

 

The experience of project

 

Visual Basic 不会在 Char 类型和数值类型之间直接转换。可以使用 Asc 或 AscW 函数将 Char 值转换为表示其码位的 Integer。可以使用 Chr 或 ChrW 函数将 Integer 值转换为具有该码位的 Char。

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