机房收费系统之余额查询

来源：互联网发布：生意参谋免费版知乎编辑：程序博客网时间：2024/04/28 18:45

机房收费系统中有几个窗体用到查询。

查询需要解决2个问题：

1、卡号已注册，即存在该怎样做

2、卡号未注册，即不存在该怎样做

下面以学生查询余额窗体为例

<span style="font-size:18px;">Private Sub Command1_Click()   Dim txtSQL As String   Dim MsgText As String   Dim mrc As ADODB.Recordset      '判断卡号收是否为空，是否是数字   If Trim(Text1.Text) = "" Then                   MsgBox "卡号不能为空！", vbOKOnly + vbExclamation, "警告"         Text1.SetFocus         Exit Sub      End If          If Not IsNumeric(Text1.Text) Then          MsgBox "请输入数字！", vbOKOnly + vbExclamation, "警告"          Exit Sub          Text1.SetFocus    End If   txtSQL = "select * from student_Info where cardno= '" & Text1.Text & "'"   Set mrc = ExecuteSQL(txtSQL, MsgText)      '检查卡号是否存在   If mrc.EOF Then        MsgBox "没有此卡号，请注册！", vbOKOnly + vbExclamation, "提示"     ' 若不存在，弹出提示框并清空文本框中内容        Text2.Text = ""        Text3.Text = ""        Text4.Text = ""        Text5.Text = ""        Text6.Text = ""        Text7.Text = ""        Text7.Text = ""        Text8.Text = ""        Text9.Text = ""        Text10.Text = ""            Else        Text2.Text = mrc.Fields(1)                                          ' 若存在，进行查询        Text3.Text = mrc.Fields(2)        Text4.Text = mrc.Fields(3)        Text5.Text = mrc.Fields(4)        Text6.Text = mrc.Fields(5)        Text7.Text = mrc.Fields(6)        Text8.Text = mrc.Fields(10)        Text9.Text = mrc.Fields(8)        Text10.Text = mrc.Fields(7)    End If      mrc.Close                                                                 '关闭数据库End Sub</span>

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