Developing COM Components using VC-ATL(3)

类别:VC语言 点击:0 评论:0 推荐:

Visual Basic、Visual C++组件调用相互通

 

n          Visual Basic调用Visual Basic组件

n          Visual C++调用Visual Basic组件

n          Visual Basic调用Visual C++组件

n          Visual C++调用Visual C++组件

 

n          编写Visual Basic组件

n          组件功能:完成三种类型的信用卡号码的合法性检查

n          编写步骤:

1.         新建一工程,工程类型选择ActiveX DLL,把工程名由默认的Project1改为ValidateCardServer,并把缺省的类模块Class1改为IValidateCard,最后在此类里敲入如下代码。

 

Option Explicit

 

Public Function fnValidateCreditCard(ByVal strCCNumber As String, ByVal strCCType As String) As Boolean

    Dim bValid As Boolean

    strCCType = Trim(strCCType)

    Select Case UCase(strCCType)

        Case "VISA"

            strCCType = "V"

        Case "MASTER"

            strCCType = "M"

        Case "American"

            strCCType = "A"

    End Select

    If fnPrefixCheck(strCCNumber, strCCType) And fnLengthCheck(strCCNumber, strCCType) And fnLuhnCheck(strCCNumber, strCCType) Then

        bValid = True

    Else

        bValid = False

    End If

    fnValidateCreditCard = bValid

End Function

 

Private Function fnPrefixCheck(strCCNumber As String, strCCType As String) As Boolean

    Dim bValidPrefix As Boolean

    Select Case UCase(strCCType)

        Case "V"

            If InStr(1, strCCNumber, "4") = 1 Then

                bValidPrefix = True

            End If

        Case "M"

            If InStr(1, strCCNumber, "51") = 1 Or _

               InStr(1, strCCNumber, "52") = 1 Or _

               InStr(1, strCCNumber, "53") = 1 Or _

               InStr(1, strCCNumber, "54") = 1 Or _

               InStr(1, strCCNumber, "55") = 1 Then

               bValidPrefix = True

            End If

        Case "A"

            If InStr(1, strCCNumber, "34") = 1 Or _

               InStr(1, strCCNumber, "37") Then

               bValidPrefix = True

            End If

    End Select

    fnPrefixCheck = bValidPrefix

End Function

 

Private Function fnLengthCheck(strCCNumber As String, strCCType As String) As Boolean

    Dim bValidLength As Boolean

    Select Case UCase(strCCType)

        Case "V"    'A visa card has a 13 digit or a 16 digit number

            If Len(strCCNumber) = 13 Or Len(strCCNumber) = 16 Then

                bValidLength = True

            End If

        Case "M"    'A mastercard has a 16 digit number

            If Len(strCCNumber) = 16 Then

                bValidLength = True

            End If

        Case "A"    'American Express has a 15 digit number

            If Len(strCCNumber) = 15 Then

                bValidLength = True

            End If

    End Select

    fnLengthCheck = bValidLength

End Function

 

Private Function fnLuhnCheck(strCCNumber As String, strCCType As String) As Boolean

    Dim bValidLuhn As Boolean

   

    Dim strRev As String

    Dim strCh As String

    Dim intNumber As Integer

    Dim strNumberFinal As String

    Dim intSum As Integer

    Dim intTemp As Integer

    strRev = StrReverse(strCCNumber)

   

    For intTemp = 1 To Len(strRev)

        strCh = Mid(strRev, intTemp, 1)

        intNumber = CInt(strCh)

        If intTemp Mod 2 = 0 Then

            intNumber = intNumber * 2

            If intNumber > 9 Then

                intNumber = intNumber - 9

            End If

        End If

        strNumberFinal = strNumberFinal & intNumber

    Next intTemp

   

    For intTemp = 1 To Len(strNumberFinal)

        intSum = intSum + Mid(strNumberFinal, intTemp, 1)

    Next intTemp

   

    If intSum Mod 10 = 0 Then

        bValidLuhn = True

    Else

        bValidLuhn = False

    End If

    fnLuhnCheck = bValidLuhn

End Function

2.         编绎组件。从File菜单中选择 Make ValidateCardServer. dll…

n          Visual Basic调用Visual Basic组件

n          编写步骤:

1.         新建一个标准工程,工程名设置为VBTestVBComProj;引入组件,选择菜单Project->References…,点击浏览,选择C:\VBCom\ ValidateCardServer.dll;敲入如下窗体代码。

 

Private Sub Command1_Click()

Dim comobj As New ValidateCardServer.IValidateCard

If comobj.fnValidateCreditCard(Text1.Text, Text2.Text) = True Then

    MsgBox "valid card"

Else

    MsgBox "invalid card"

End If

End Sub

2.         编绎运行测试程序。

n          代码测试:在信用卡号码中输入4567890123456783,在信用卡类型中输入visa,点击确定,弹出"valid card"的提示框;在信用卡号码中输入4567890123456789,在信用卡类型中输入visa,点击确定按钮,弹出"invalid card"的提示框。

 

 

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