Wildcard Replace using the VB.NET Replace function

Wildcard Replace using the VB.NET Replace function

• S Hussain

  what you have there is basically a wildcard search followed by a replace.
  
  The instr function will also be helpful.
  
  I wrote a parser a long time ago. I don't know whether this will help or not.
  
  Private Sub Parse()

          Dim i As Integer
          Dim illegalchars = "\/<>:;""'|^ "
          bListAllFiles = False
          bFullnameCompare = False
          bExtCompare = False
          bNameCompare = False
          bNamescan = False
          bExtscan = False
          bRequiredActions = 0

          sFilestring = tb1.Text.Trim
          Dim ISlm1 As Short = sFilestring.Length - 1

          'Scan for illegal characters

          If sFilestring <> "" Then
              For ii As Short = 0 To ISlm1
                  For i = 0 To illegalchars.length - 1
                      If sFilestring(ii) = illegalchars(i) Then
                          Dim status As Integer = MsgBox("'" & sFilestring(ii) & "' is an illegal filename character." & vbCrLf & "Do you want to continue ", MsgBoxStyle.YesNo, _
                          "Illegal Character")
                          If status = Microsoft.VisualBasic.MsgBoxResult.Yes Then
                              Exit For
                          Else
                              GoTo Common_Exit
                          End If

                      End If
                  Next
              Next
          Else
              bListAllFiles = True
              bRequiredActions += 1
              GoTo Common_Exit
          End If

  
          ' One contiguous asterisk please

          While sFilestring.Contains("**")
              sFilestring = sFilestring.Replace("**", "*")
          End While

  
          If ((sFilestring = "") Or (sFilestring = "*") Or sFilestring = ("*.*") Or sFilestring = ("*.") _
          Or sFilestring = (".*")) Then
              bListAllFiles = True
              bRequiredActions += 1
              GoTo Common_Exit
          End If

          Dim StarCount As Short
          Dim DotCount As Short

          ISlm1 = sFilestring.Length - 1 ' Recalculate

          For i = 0 To ISlm1
              If sFilestring(i) = "*" Then StarCount += 1
              If sFilestring(i) = "." Then DotCount += 1
          Next

  
          If (((StarCount = 0) And (DotCount = 0)) And ISlm1 > 0) Then
              bFullnameCompare = True
              bRequiredActions += 1
              GoTo Common_Exit
          End If

  
          Dim name As String = sFilestring.Substring(0, sFilestring.LastIndexOf("."))
          Dim ext As String = sFilestring.Substring(sFilestring.LastIndexOf(".") + 1, ISlm1 - sFilestring.LastIndexOf("."))

          If (Not name.Contains("*")) And (Not ext.Contains("*")) Then
              bFullnameCompare = True
              bRequiredActions += 1
              GoTo Common_Exit
          End If

  
          If Not name.Contains("*") And ext = "*" Then
              bNameCompare = True
              bRequiredActions += 1
              GoTo Common_Exit
          End If

          If Not ext.Contains("*") And name = "*" Then
              bExtCompare = True
              bRequiredActions += 1
              GoTo Common_Exit
          End If

          If Not name.Contains("*") And name.Length > 0 Then
              bNameCompare = True
              bRequiredActions += 1
          End If

          If Not ext.Contains("*") And ext.Length > 0 Then
              bExtCompare = True
              bRequiredActions += 1
          End If

          'do a name scan

  
          SplitI(name, "*", NameDict)
          Select Case NameDict.Count
              Case Is = 1
                  bNameCompare = True
              Case Is > 1
                  bNamescan = True
                  bRequiredActions += 1
          End Select

  
          SplitI(ext, "*", ExtDict)
          Select Case ExtDict.Count
              Case Is = 1
                  bExtCompare = True
              Case Is > 1
                  bExtscan = True
                  bRequiredActions += 1
          End Select

  
  Common_Exit:

  
  
  

• favio

  Surprisingly enough wild carding is complex. I've actually seen multipage papers from Microsoft describing their wildcarding. It is not simple.
  
  The complexity is in the frontend. That is breaking a request into substrings. The back end that does a search is a standard string search.
  
  I am not a mistress in parsing and do not pretend to be. But that's what is required in straight code to wild card a filename.
  
  Perhaps someone with expertise in regular expressions will come along with something simpler but I kind of doubt it. The microsoft paper on wildcarding was rather long.
  
  I do see where I could have used splits instead of loops. That would have made things MUCH shorter.
  
  

• vdinenna

  How about regular expressions
  str1 = system.text.regularexpressions.regex.replace(str1,"Test.*", "Test")
  
  Very powerful and therefore complex, check out:
  http://www.regular-expressions.info/
  
  John.
  
  
  
  
  

• Radi Naydenov

  Thanks for that, but im not too sure whether that will do what im after... Basically i am doing a find and replace for my application, and i want to support wildcards like the find and replace in VB.NET works. It doesnt need to be as complex, it just needs to support the and * wildcards.
  
• Wildcard Replace using the VB.NET Replace function