Retrieve Environment Variables

   1: ''' <summary>

   2: ''' Class to retrieve environment variables and custom declared variables with following format %VARIABLE%

   3: ''' </summary>

   4: ''' <remarks>A class used to read a string and transform all known variables with format %VARIABLE%,returning the converted string</remarks>

   5: Public Class VariableRetriever

   6:  

   7:     #Region "Methods"

   8:  

   9:     ''' <summary>

  10:     ''' Converts all known variables with format %VARIBALE% in the provided string

  11:     ''' </summary>

  12:     ''' <param name="str">Provide a string to transform</param>

  13:     ''' <returns>Returns the converted string</returns>

  14:     ''' <remarks>If an error occurs an empty string will be returned</remarks>

  15:     Protected Friend Shared Function GetAllVarFromString(ByVal str As String) As String

  16:         'try to get all the special %xxx% from the string

  17:         'replace and rebuild string

  18:         Try

  19:         

  20:             Dim split() As String = Nothing

  21:             Dim i As Integer = 0

  22:             Dim var As String = Nothing

  23:             Dim firstindex As Integer = Nothing

  24:             Dim secondindex As Integer = Nothing

  25:             If Not String.IsNullOrEmpty(str) Then

  26:                 If str.Contains("%") Then

  27:                     Do Until str.Contains("%") = False

  28:                         firstindex = Nothing

  29:                         secondindex = Nothing

  30:                         var = Nothing

  31:  

  32:                         firstindex = str.IndexOf("%")

  33:                         If Not firstindex = -1 Then

  34:                             secondindex = str.IndexOf("%", firstindex + 1)

  35:                             If Not secondindex = -1 Then

  36:                                 var = str.Substring(firstindex + 1, secondindex - firstindex - 1)

  37:                                 ReDim Preserve split(i)

  38:                                 split(i) = str.Substring(0, firstindex)

  39:                                 i = i + 1

  40:                                 ReDim Preserve split(i)

  41:                                 split(i) = GetVar(var)

  42:                                 str = str.Remove(0, secondindex + 1)

  43:                                 i = i + 1

  44:                             End If

  45:                         End If

  46:                     Loop

  47:                     ReDim Preserve split(i)

  48:                     split(i) = str

  49:                     If Not split.Length > 0 Then

  50:                         Return str

  51:                     Else

  52:                         Return Join(split, "")

  53:                     End If

  54:                 Else

  55:                     Return str

  56:                 End If

  57:             Else

  58:                 Return str

  59:             End If

  60:         Catch ex as Exception

  61:             Return ""

  62:         End Try

  63:     End Function 'End Method GetAllVarFromString

  64:  

  65:     ''' <summary>

  66:     ''' Converts a %VARIABLE% to it's value

  67:     ''' </summary>

  68:     ''' <param name="variable">Provide a variable %VARIABLE% as string</param>

  69:     ''' <returns>Returns converted string</returns>

  70:     ''' <remarks></remarks>

  71:     Protected Friend Shared Function GetVar(ByVal variable As String) As String

  72:         Try

  73:             If Not String.IsNullOrEmpty(variable) Then

  74:                 variable = RemoveProcents(variable)

  75:                 'Here you can add some variables

  76:                 'A few examples %APPPATH% will return the application startup path

  77:                 '%APPNAME% just gets the filename without extension

  78:                 Select Case UCase(variable)

  79:                     Case "APPPATH"

  80:                         Return Application.StartupPath

  81:                     Case "APPNAME"

  82:                         Return IO.Path.GetFileNameWithoutExtension(Application.ExecutablePath)

  83:                     Case Else

  84:                         Return Environment.GetEnvironmentVariable(RemoveProcents(variable))

  85:                 End Select

  86:             Else : Return variable

  87:             End If

  88:  

  89:         Catch ex As Exception

  90:             Return ""

  91:         End Try

  92:     End Function 'End Method GetVar

  93:     

  94:     ''' <summary>

  95:     ''' Removes all % characters in a string

  96:     ''' </summary>

  97:     ''' <param name="str">Provide a string</param>

  98:     ''' <returns>Returns a string with % characters stripped</returns>

  99:     ''' <remarks></remarks>

 100:     Private Shared Function RemoveProcents(ByVal str As String) As String

 101:         If Not String.IsNullOrEmpty(str) Then

 102:             str = Replace(str, "%", "")

 103:         End If

 104:         Return str

 105:     End Function 'End Method RemoveProcents

 106:  

 107: #End Region 'Methods

 108:  

 109: End Class 'End Type VariableRetriever

 110: