【机房收费系统】充值

 充值窗体流程图：

部分重要代码：

 If Not testtxt(txtcardno.Text) Then     '判断卡号是否为空
        MsgBox "请输入卡号！", vbOKOnly + vbExclamation, "警告"
        txtcardno.SetFocus
        Exit Sub
    End If
    If Not testtxt(txtrecharge.Text) Then       '判断充值金额是否为空
        MsgBox "请输入充值金额！", vbOKOnly + vbExclamation, "警告"
        txtrecharge.SetFocus
        Exit Sub
    End If
    Rem:从student_info中查找
    txtsql = "select * from student_info where cardno='" & txtcardno.Text & "'"
    Set mrc = executeSQL(txtsql, msgtext)
    If mrc.EOF Then
        MsgBox "该卡号不存在！", vbOKOnly + vbExclamation, "警告"
        mrc.Close
        txtcardno.SetFocus
        Exit Sub
    Else
        mrc.Close
    End If
        Rem:从basicdata_info中查找
    txtsql = "select * from BasicData_info"
    Set mrc = executeSQL(txtsql, msgtext)

        Rem:充值金额是否小于最小金额
    If Val(txtrecharge.Text) < mrc.Fields(5) Then
        MsgBox "充值金额不能小于" & Trim(mrc.Fields(5)) & "元", vbOKOnly + vbExclamation, "警告"
        mrc.Close
        Exit Sub
    End If

        mrc.Close
    txtsql = "select * from student_info where cardno='" & Trim(txtcardno.Text) & "'"
    Set mrc = executeSQL(txtsql, msgtext)
    txtsql = "select * from recharge_info where cardno='" & Trim(txtcardno.Text) & "'"
    Set mrc1 = executeSQL(txtsql, msgtext)
        mrc1.AddNew
        mrc1.Fields(1) = mrc.Fields(1)
        mrc1.Fields(2) = Trim(txtcardno.Text)
        mrc1.Fields(3) = Val(Trim(txtrecharge.Text))
        mrc1.Fields(4) = Trim(Date)
        mrc1.Fields(5) = Trim(Time)
        mrc1.Fields(6) = username
        mrc1.Fields(7) = Trim("未结账")
        mrc1.Update

    txtsql = "select * from student_info where cardno='" & Trim(txtcardno.Text) & "'"
    Set mrc = executeSQL(txtsql, msgtext)
        mrc.Fields(7) = Val(Trim(txtrecharge.Text)) + mrc.Fields(7)
        mrc.Fields(12) = Trim(Date)
        mrc.Fields(13) = Trim(Time)
        mrc.Update
        mrc.Close
txtsql = "select * from student_info where cardno='" & Trim(txtcardno.Text) & "'"
Set mrc = executeSQL(txtsql, msgtext)
txt.Text = "充值卡号:" & txtcardno.Text & vbCrLf & vbCrLf & "上次卡内的余额：" & Trim(mrc.Fields(7)) - txtrecharge.Text & vbCrLf & vbCrLf & "现在卡内的余额：" & mrc.Fields(7) & vbCrLf & vbCrLf & "充值日期：" & mrc.Fields(12) & vbCrLf & vbCrLf & "充值时间：" & mrc.Fields(13) & vbCrLf & vbCrLf & "充值老师：" & username

 文本框不能输入：

Private Sub txt_KeyPress(KeyAscii As Integer)
    KeyAscii = 0
End Sub