VB.NET之旅—文本框内字符串的检验(机房收费系统重构个人版)

#Region "检验文本框字符串是否符合要求四部曲"

    '1-----去除文本左右两边的空格
    Public Function ClearSpace(ByVal txtbox As TextBox)
        Return txtbox.Text.ToString.Trim()
    End Function

    '2-----**不能为空
    Public Sub notEmpty(ByVal txtbox As TextBox,ByVal lbl1 As Label,ByVal lbl2 As Label)
        Dim x As Int16 = lbl2.Text.ToString.Trim.Length - 1 '设置字符串长度为减一，以去掉冒号
        lbl1.ForeColor = Color.Red
        lbl1.Text = lbl2.Text.Substring(0,x) & ",不能为空"
        txtbox.Focus()
    End Sub

    '3------字符串不符合要求
    Public Sub notMatch(ByVal txtbox As TextBox,ByVal lbl As Label,ByVal reminder As String)
        lbl.ForeColor = Color.Red
        lbl.Text = reminder
        txtbox.Focus()
        txtbox.SelectAll()
    End Sub

    '4-----文本框输入正确
    Public Sub Correct(ByVal lbl As Label)
        lbl.ForeColor = Color.Green
        lbl.Text = "√"
    End Sub
#End Region

我们接下来看一下调用过程：

  '验证用户名是否为空和验证此用户是否存在
  Public Sub IsNameRight()
    If ClearSpace(Me.txtName) = "" Then
      notEmpty(Me.txtName,Me.lblUserName,Me.lblUserName1)
      Exit Sub
    Else
      username = txtName.Text.ToString.Trim


      admininfo1 = manager.selectAdmin_info(username)
      If admininfo1 Is Nothing Then
        notMatch(Me.txtName,"用户名错误")


        Exit Sub
      Else


        Correct(Me.lblUserName)
      End If
    End If
  End Sub




  Private Sub txtName_LostFocus(ByVal sender As Object,ByVal e As System.EventArgs) Handles txtName.LostFocus
    IsNameRight()
  End Sub

这样是不是省了不少事啊，例如对

txtbox.Focus()

txtbox.SelectAll()

的不断重复书写，呵呵，大家不妨尝试一下！