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VB.net的特殊语法（区别于C#.NET）

2024-07-25 21:40:12   216人阅读

1:引入命名空间（Imports）

Imports System.ExceptionImports System.Data.SqlClientImports System.Security.CryptographyImports System.Text.StringBuilder

2：实例化类

Dim myConn As SqlConnectionmyConn = New SqlConnection(ConnString)

3：IF THEN ELSE END块

If Not IsPostBack() Then     txtEmployee.Text = ""     txtPassWord.Text = ""else　　txtEmployee.Text = "      txtPassWord.Text = ""End If

4:Try catch Fanally End Try块

Try    myConn = New SqlConnection(ConnString)    myConn.Open()Catch ex As Exception    Throw New Exception(ex.Message & "clsDatabaseAccess.GetDataBase()")Finally    myConn.Close()    myConn = NothingEnd Try

5：Sub块

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load        Try            If Not IsPostBack() Then                txtEmployee.Text = ""                txtPassWord.Text = ""            End If        Catch ex As Exception            Response.Write(ex.Message)        End TryEnd Sub

6：函数块（function）

    Private Function ByteArrayToString(ByVal arrInput() As Byte) As String        Dim i As Integer        Dim sOutput As New System.Text.StringBuilder(arrInput.Length)        For i = 0 To arrInput.Length - 1            sOutput.Append(arrInput(i).ToString("X2"))        Next        Return sOutput.ToString()    End Function

7：变量定义

        Dim bytMessage As Byte()        Dim bytMD5 As Byte()        Dim strMD5 As String        Dim strPassword As String        Dim Readlen As Integer

　　　　　‘数组定义
        Dim tTfile() As String = Split(tfileN.Trim, "\")
        Dim MD5 As New      System.Security.Cryptography.MD5CryptoServiceProvider

8：数据库连接获取DS方法

WEBConfig中配置数据库连接字符串

<appSettings>    <add key="ConnectionString" value="server=1.1.1.1; database=dbTest;user=test;password=test"></add></appSettings>

取得WEbCnfig中配置的特定字符串的值：

Private strConnectString = System.Configuration.ConfigurationSettings.AppSettings.Get("ConnectPassWord")

数据库连接并返回ds：

        Dim myConn As SqlConnection        Dim myDataAdapter As SqlDataAdapter        Dim ds As DataSet        Try            myConn = New SqlConnection(ConnString)            myConn.Open()                       strSql = "select EmployeeManagementID from mstEmployeeBasic where EmployeeCode =" & txtEmployee.Text.Trim().ToString()            myDataAdapter = New SqlDataAdapter(Sql, myConn)            Dim ds As New DataSet            myDataAdapter.Fill(ds)            GetDataBase = ds                    If Not (ds.Tables(0).Rows.Count > 0) Then                txtEmployee.Text = ""                txtPassWord.Text = ""            Else                txtEmployee.Text = ""            End If        Catch ex As Exception            Throw New Exception(ex.Message & "clsDatabaseAccess.GetDataBase()")        Finally            myConn.Close()            myConn = Nothing        End Try

9：后台提示信息在前台显示：

Response.Write("<script lanugage=‘javascript‘>alert(‘パスワードが間違いました。‘);</script>")

10：后台页面跳转：

Response.Redirect("TestPaperList.aspx?code=" & StrConv(txtEmployee.Text.Trim(), VbStrConv.Narrow) & "")

 11：后台取URL传过来的参数的值

            employeecode = Request.QueryString("code")            AdminType = Request.QueryString("type")

12:在Vb.net中 用me代替了this

                Me.txtCode.Text = ""                Me.txtPassword1.Text = ""                Me.txtPassword2.Text = ""

13:类型转换

                intCode = CInt(employeecode.Trim())                intType = CInt(AdminType.Trim)

14：拼接数据库字符串

            strSql = ""            strSql = strSql & "insert into                                      " & vbCrLf            strSql = strSql & "   administrator values(                          " & vbCrLf            strSql = strSql & "         <$code>                                  " & vbCrLf            strSql = strSql & "        ,‘<$password>‘                            " & vbCrLf            strSql = strSql & "        ,<$type>)                                  " & vbCrLf            strSql = Replace(strSql, "<$code>", code.ToString)            strSql = Replace(strSql, "<$password>", password.Trim.Replace("‘", "‘‘"))            strSql = Replace(strSql, "<$type>", type.ToString)

15：For循环块

Dim i As Integer = 0
For i = 0 To dsSelectedEmployee.Tables(0).Rows.Count - 1     lstSelected.Items(i).Text = dsSelectedEmployee.Tables(0).Rows(i)(0) & " " & dsSelectedEmployee.Tables(0).Rows(i)(1)Next

16：下拉框绑定值

        Dim dsSelectedEmployee As DataSet        Try            If Me.dlstClass.SelectedIndex <> 0 Then                dsSelectedEmployee = GetAnswerer()                Me.lstSelected.DataValueField = "EmployeeNo"                Me.lstSelected.DataSource = dsSelectedEmployee.Tables(0)                Me.lstSelected.DataBind()                Dim i As Integer = 0                For i = 0 To dsSelectedEmployee.Tables(0).Rows.Count - 1                    lstSelected.Items(i).Text = dsSelectedEmployee.Tables(0).Rows(i)(0) & " " & dsSelectedEmployee.Tables(0).Rows(i)(1)                Next            Else                Me.lstSelected.Items.Clear()            End If        Catch ex As Exception            Response.Write(ex.Message)        End Try

 

VB.net的特殊语法（区别于C#.NET）


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