tools.vb

来自「酒店管理系统使用VB开发.数据库采用微软公司的SQL」· VB 代码 · 共 86 行

Imports Microsoft.VisualBasic
Imports System.Web

Public Class Tools

    Public Shared Function IsLoggedIn() As Boolean

        Dim ctx As HttpContext = HttpContext.Current

        If ctx.Session("loginID") Is Nothing OrElse _
           ctx.Session("loginID") = "" Then
            Return False
        Else
            Return True
        End If

    End Function
    Public Shared Function FixNull(ByVal dbvalue) As String
        If dbvalue Is DBNull.Value Then
            Return ""
        Else
            'NOTE: This will cast value to string if
            'it isn't a string.

            Return dbvalue.ToString
        End If
    End Function

    Public Shared Function FixNullNo(ByVal dbvalue) As Decimal
        If dbvalue Is DBNull.Value Then
            Return 0
        Else
            'NOTE: This will cast value to string if
            'it isn't a string.

            Return dbvalue
        End If
    End Function

 Public Shared Function Encrypt(ByVal strText As String)
        Dim Combine As String, i As Integer, Temp As String
        Combine = ""
        Temp = ""

        For i = 1 To Len(strText) - 1 Step 2

            If Len(Trim(Str(Asc(Mid(strText, i, 1))))) < 3 Then
                Temp = "0" & Trim(Str(Asc(Mid(strText, i, 1))))
            Else
                Temp = Trim(Str(Asc(Mid(strText, i, 1))))
            End If
            Combine = Combine & Temp

            If Len(Trim(Str(Asc(Mid(strText, i + 1, 1))))) < 3 Then
                Temp = "0" & Trim(Str(Asc(Mid(strText, i + 1, 1))))
            Else
                Temp = Trim(Str(Asc(Mid(strText, i + 1, 1))))
            End If
            Combine = Combine & Temp
        Next i
        Temp = ""

        For i = 1 To Len(Combine)
            Temp = Temp & Chr(Asc(Mid(Combine, i, 1)) + 128)
        Next i
        Encrypt = Temp
    End Function

    Public Shared Function Decrypt(ByVal strText As String)
        Dim Combine As String, i As Integer, Temp As String, Temp2 As Integer
        Combine = ""

        For i = 1 To Len(strText)
            Combine = Combine & Chr(Asc(Mid(strText, i, 1)) - 128)
        Next i
        Temp = ""

        For i = 1 To Len(Combine) Step 3
            Temp2 = Mid(Combine, i, 3)
            Temp = Temp & Chr(Temp2)
        Next i
        Decrypt = Temp
    End Function
End Class