BC30109_'String' is a class type and cannot be used as an expression.

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  Hi

  Maybe this. It creates a string buffer of the length of the 1NameLength value (I used 12345678 for testing)

  Dim lNameLength As Long = 12345678
  Dim sNameBuffer As String = StrDup(CInt(lNameLength), vbNullChar)
  
  Dim len As Integer = sNameBuffer.Length
  ' provides a string buffer of 12345678
  
  

  
  

  ---

  Regards Les, Livingston, Scotland

  Thursday, December 12, 2019 10:26 PM
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  Perhaps if I include the entire text example. Generally the Cint recommendation fixed the errors, but I started getting warning flags and debugging errors while using the buttons. Seems: Wend to End While and the label to label.Text instead of label.caption. The string error though. I've never had an issue with using certain cryptography in Windows10 from text examples, but I like the project of eventually getting back to a file on the C:drive of a SHA2 or similar with something neat like changing a table Matrix to show a red X instead of any M if a different or base file is used.

  
  

  It's a form with three buttons and a label. I'm assuming the exercise is for showing which SHA, DES, MD5;2,etc., are on the computer.

  'VERSION 5.00
  'Begin VB.Form frmCSPs
     '...Public Class Form1 with 3 buttons and a label

  '//////////////////////////////////////////////////////////////////////////////////

  Option Explicit

  'Public Class...form1_load(...

  Private Declare Function CryptEnumProviderTypes Lib "advapi32.dll" Alias "CryptEnumProviderTypesA" ( _
      ByVal dwIndex As Long, _
      ByVal pdwReserved As Long, _
      ByVal dwFlags As Long, _
      pdwProvType As Long, _
      ByVal pszTypeName As String, _
      pcbTypeName As Long) As Long

  Private Declare Function CryptEnumProviders Lib "advapi32.dll" Alias "CryptEnumProvidersA" ( _
      ByVal dwIndex As Long, _
      ByVal pdwReserved As Long, _
      ByVal dwFlags As Long, _
      pdwProvType As Long, _
      ByVal pszProvName As String, _
      pcbProvName As Long) As Long

      Private Sub cmdlistCSPs_Click(sender As Object, e As EventArgs) Handles cmdlistCSPs.Click
          EnumCSPs()
      End Sub

      Private Sub cmdTypes_Click(sender As Object, e As EventArgs) Handles cmdTypes.Click
          EnumTypes()
      End Sub

      Private Sub cmdExit_Click(sender As Object, e As EventArgs) Handles cmdExit.Click
          Me.Close()
      End Sub

  Private Sub EnumCSPs()
  '*************************************************************
  '* Written By: Davis Chapman
  '* Date:       September 22, 1999
  '*
  '* Syntax:     EnumCSPs
  '*
  '* Parameters:  None
  '*
  '* Purpose: This subroutine loops through all of the CSPs
  '*          installed on the system, listing them for the user.
  '*************************************************************
      Dim lResult As Long
      Dim lIndex As Long
      Dim sNameBuffer As String
      Dim lNameLength As Long
      Dim lProvType As Long
     
      '--- Initialize the necessary variables
      lIndex = 0
      lblList.Caption = ""
     
      '--- Determine the size of the buffer needed
      lResult = CryptEnumProviders(lIndex, 0, 0, lProvType, vbNullString, lNameLength)
     
      '--- Prepare a string buffer for the CryptEncrypt function
      sNameBuffer = String(lNameLength, vbNullChar)
     
      '--- Get the provider name, looping until all providers have been listed
      While CBool(CryptEnumProviders(lIndex, 0, 0, lProvType, sNameBuffer, _
              lNameLength))
         
          '--- Add the current CSP to the display list
          If (lIndex > 0) Then lblList.Caption = lblList.Caption + vbCrLf
          lblList.Caption = lblList.Caption + sNameBuffer
         
          '--- Increment the index counter
          lIndex = lIndex + 1
         
          '--- Determine the size of the buffer needed
          lResult = CryptEnumProviders(lIndex, 0, 0, lProvType, vbNullString, lNameLength)
         
          '--- Prepare a string buffer for the CryptEncrypt function
          sNameBuffer = String(lNameLength, vbNullChar)
      Wend
  End Sub

  Private Sub EnumTypes()
  '*************************************************************
  '* Written By: Davis Chapman
  '* Date:       September 22, 1999
  '*
  '* Syntax:     EnumTypes
  '*
  '* Parameters:  None
  '*
  '* Purpose: This subroutine loops through all of the CSP types
  '*          installed on the system, listing them for the user.
  '*************************************************************
      Dim lResult As Long
      Dim lIndex As Long
      Dim sNameBuffer As String
      Dim lNameLength As Long
      Dim lProvType As Long
     
      '--- Initialize the necessary variables
      lIndex = 0
      lblList.Caption = ""
     
      '--- Determine the size of the buffer needed
      lResult = CryptEnumProviderTypes(lIndex, 0, 0, lProvType, vbNullString, lNameLength)
     
      '--- Prepare a string buffer for the CryptEncrypt function
      sNameBuffer = String(lNameLength, vbNullChar)
     
      '--- Get the type name, looping until all types have been listed
      While CBool(CryptEnumProviderTypes(lIndex, 0, 0, lProvType, sNameBuffer, _
              lNameLength))
         
          '--- Add the current CSP to the display list
          If (lIndex > 0) Then lblList.Caption = lblList.Caption + vbCrLf
          lblList.Caption = lblList.Caption + sNameBuffer
         
          '--- Increment the index counter
          lIndex = lIndex + 1
         
          '--- Determine the size of the buffer needed
          lResult = CryptEnumProviderTypes(lIndex, 0, 0, lProvType, vbNullString, lNameLength)
         
          '--- Prepare a string buffer for the CryptEncrypt function
          sNameBuffer = String(lNameLength, vbNullChar)
      Wend
  End Sub

  'End Class

  Friday, December 13, 2019 12:20 AM
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   but seems the IDE is asking a function as a string with sNameBuffer = String(lNameLength, vbNullChar) . Any help
  

  What do you mean by: "asking a function as a string"?
  
  "String" is a .NET class:
  
  String Class
  https://docs.microsoft.com/en-us/dotnet/api/system.string?view=netframework-4.8
  
  The expression: String(lNameLength, vbNullChar)
  has the syntax of a Function call.
  
  It is not a correct syntax for constructing a String, if that is what was
  intended. If the program has a Function named "String" defined then that 
  name should be changed, or qualified so that it can be distinguished from 
  System.String.
  
  <typename>' is a class type and cannot be used as an expression
  https://docs.microsoft.com/en-us/dotnet/visual-basic/misc/bc30109
  
  - Wayne
  

  Friday, December 13, 2019 12:36 AM
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  Perhaps if I include the entire text example. Generally the Cint recommendation fixed the errors, but I started getting warning flags and debugging errors while using the buttons. Seems: Wend to End While and the label to label.Text instead of label.caption. The string error though. I've never had an issue with using certain cryptography in Windows10 from text examples, but I like the project of eventually getting back to a file on the C:drive of a SHA2 or similar with something neat like changing a table Matrix to show a red X instead of any M if a different or base file is used.

  
  

  It's a form with three buttons and a label. I'm assuming the exercise is for showing which SHA, DES, MD5;2,etc., are on the computer.

  'VERSION 5.00
  'Begin VB.Form frmCSPs
     '...Public Class Form1 with 3 buttons and a label

  '//////////////////////////////////////////////////////////////////////////////////

  Option Explicit

  'Public Class...form1_load(...

  Private Declare Function CryptEnumProviderTypes Lib "advapi32.dll" Alias "CryptEnumProviderTypesA" ( _
      ByVal dwIndex As Long, _
      ByVal pdwReserved As Long, _
      ByVal dwFlags As Long, _
      pdwProvType As Long, _
      ByVal pszTypeName As String, _
      pcbTypeName As Long) As Long

  Private Declare Function CryptEnumProviders Lib "advapi32.dll" Alias "CryptEnumProvidersA" ( _
      ByVal dwIndex As Long, _
      ByVal pdwReserved As Long, _
      ByVal dwFlags As Long, _
      pdwProvType As Long, _
      ByVal pszProvName As String, _
      pcbProvName As Long) As Long

      Private Sub cmdlistCSPs_Click(sender As Object, e As EventArgs) Handles cmdlistCSPs.Click
          EnumCSPs()
      End Sub

      Private Sub cmdTypes_Click(sender As Object, e As EventArgs) Handles cmdTypes.Click
          EnumTypes()
      End Sub

      Private Sub cmdExit_Click(sender As Object, e As EventArgs) Handles cmdExit.Click
          Me.Close()
      End Sub

  Private Sub EnumCSPs()
  '*************************************************************
  '* Written By: Davis Chapman
  '* Date:       September 22, 1999
  '*
  '* Syntax:     EnumCSPs
  '*
  '* Parameters:  None
  '*
  '* Purpose: This subroutine loops through all of the CSPs
  '*          installed on the system, listing them for the user.
  '*************************************************************
      Dim lResult As Long
      Dim lIndex As Long
      Dim sNameBuffer As String
      Dim lNameLength As Long
      Dim lProvType As Long
     
      '--- Initialize the necessary variables
      lIndex = 0
      lblList.Caption = ""
     
      '--- Determine the size of the buffer needed
      lResult = CryptEnumProviders(lIndex, 0, 0, lProvType, vbNullString, lNameLength)
     
      '--- Prepare a string buffer for the CryptEncrypt function
      sNameBuffer = String(lNameLength, vbNullChar)
     
      '--- Get the provider name, looping until all providers have been listed
      While CBool(CryptEnumProviders(lIndex, 0, 0, lProvType, sNameBuffer, _
              lNameLength))
         
          '--- Add the current CSP to the display list
          If (lIndex > 0) Then lblList.Caption = lblList.Caption + vbCrLf
          lblList.Caption = lblList.Caption + sNameBuffer
         
          '--- Increment the index counter
          lIndex = lIndex + 1
         
          '--- Determine the size of the buffer needed
          lResult = CryptEnumProviders(lIndex, 0, 0, lProvType, vbNullString, lNameLength)
         
          '--- Prepare a string buffer for the CryptEncrypt function
          sNameBuffer = String(lNameLength, vbNullChar)
      Wend
  End Sub

  Private Sub EnumTypes()
  '*************************************************************
  '* Written By: Davis Chapman
  '* Date:       September 22, 1999
  '*
  '* Syntax:     EnumTypes
  '*
  '* Parameters:  None
  '*
  '* Purpose: This subroutine loops through all of the CSP types
  '*          installed on the system, listing them for the user.
  '*************************************************************
      Dim lResult As Long
      Dim lIndex As Long
      Dim sNameBuffer As String
      Dim lNameLength As Long
      Dim lProvType As Long
     
      '--- Initialize the necessary variables
      lIndex = 0
      lblList.Caption = ""
     
      '--- Determine the size of the buffer needed
      lResult = CryptEnumProviderTypes(lIndex, 0, 0, lProvType, vbNullString, lNameLength)
     
      '--- Prepare a string buffer for the CryptEncrypt function
      sNameBuffer = String(lNameLength, vbNullChar)
     
      '--- Get the type name, looping until all types have been listed
      While CBool(CryptEnumProviderTypes(lIndex, 0, 0, lProvType, sNameBuffer, _
              lNameLength))
         
          '--- Add the current CSP to the display list
          If (lIndex > 0) Then lblList.Caption = lblList.Caption + vbCrLf
          lblList.Caption = lblList.Caption + sNameBuffer
         
          '--- Increment the index counter
          lIndex = lIndex + 1
         
          '--- Determine the size of the buffer needed
          lResult = CryptEnumProviderTypes(lIndex, 0, 0, lProvType, vbNullString, lNameLength)
         
          '--- Prepare a string buffer for the CryptEncrypt function
          sNameBuffer = String(lNameLength, vbNullChar)
      Wend
  End Sub

  'End Class

  This is not VB.NET code at all. If you want to use VB.NET you best option is to start with a clean slate. If this is for VB Classic then go to the following link for VB Classic

  http://www.vbforums.com/forumdisplay.php?1-Visual-Basic-6-and-Earlier

  When coding in VB.NET its best to forget old ways of coding and learn new ways to code.

  ---

  Please remember to mark the replies as answers if they help and unmarked them if they provide no help, this will help others who are looking for solutions to the same or similar problem. Contact via my Twitter (Karen Payne) or Facebook (Karen Payne) via my MSDN profile but will not answer coding question on either.

  NuGet BaseConnectionLibrary for database connections.

  StackOverFlow
  

  Friday, December 13, 2019 12:39 AM
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  Hi

  To make the code more readable, please use the code block tool.

  

  ---

  Regards Les, Livingston, Scotland

  Friday, December 13, 2019 12:41 AM
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   sNameBuffer = String(lNameLength, vbNullChar) . 
  

  Also see this thread:
  
  equivalent of vb 6 string
  https://social.msdn.microsoft.com/Forums/en-US/45721253-d8f3-42fc-933c-5343531f9fcc/equivalent-of-vb-6-string
  
  - Wayne
  

  Friday, December 13, 2019 12:48 AM
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  The Chapman text wasn't clear beyond Visual Basic applications. Messing around it seems Windows10 has simple3des, SHA1 and RSA. Somewhere around New Filestream is a little abstract, but I'm not even at form headers yet. Windows Forms (Visual Basic, .NET) is what I usually select in Visual Studio. Basically learning Visual Basic from a VBA transition. We had our Access files basically like MVC, but VBA.

  It encrypts and gives a message box with a signature(1form,1button), but close to the general project:

  Imports System.Security.Cryptography
  Imports System.IO
  Public Class Dashboard
      Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
          Dim plainText As String = InputBox("Text to Encrypt:")
          Dim password As String = InputBox("Enter a Password:")
          Dim wrapper As New Simple3Des(password)
          Dim cipherText As String = wrapper.EncryptData(plainText)
          'MsgBox("The cipher text is: " & cipherText)
          My.Computer.FileSystem.WriteAllText(
          My.Computer.FileSystem.SpecialDirectories.MyDocuments &
          "\cipherText.txt", cipherText, False)
          Dim password1 As String = "Password"
          'Create Password Key
          Dim SaltValueBytes As Byte() =
              System.Text.Encoding.ASCII.GetBytes("This is my salt")
          Dim passwordKey As Rfc2898DeriveBytes =
              New Rfc2898DeriveBytes(password1, SaltValueBytes)
          Dim alg As RijndaelManaged = New RijndaelManaged
          alg.Key = passwordKey.GetBytes(alg.KeySize / 8)
          alg.IV = passwordKey.GetBytes(alg.BlockSize / 8)
          'Read the unencrypted file into filedata
          Dim inFile As FileStream = New FileStream(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\cipherText.txt", FileMode.Open, FileAccess.Read)
          Dim fileData(inFile.Length) As Byte
          inFile.Read(fileData, 0, CType(inFile.Length, Integer))
          'Create the ICryptoTransform and CryptoStream object
          Dim encryptor As ICryptoTransform = alg.CreateEncryptor
          inFile.Close()
          Dim outFile As FileStream = New FileStream(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\cipherText.txt", FileMode.OpenOrCreate, FileAccess.Write)
          Dim encryptStream As CryptoStream = New CryptoStream(outFile, encryptor, CryptoStreamMode.Write)
          'Write contents to the CryptoStream
          encryptStream.Write(fileData, 0, fileData.Length)
          'Close the file handles
          encryptStream.Close()
          outFile.Close()
          Dim signer As RSACryptoServiceProvider = New RSACryptoServiceProvider
          'step 2
          Dim file As FileStream = New FileStream(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\cipherText.txt", FileMode.Open, FileAccess.Read)
          Dim reader As BinaryReader = New BinaryReader(file)
          Dim data As Byte() = reader.ReadBytes(CType(file.Length, Integer))
          'step 3// Calling SignData method and store signature
          Dim signature As Byte() = signer.SignData(data, New SHA1CryptoServiceProvider)
          'step 4// Export the public key
          Dim publicKey As String = signer.ToXmlString(False)
          MsgBox("Signature: " + Convert.ToBase64String(signature))
          reader.Close()
          file.Close()
      End Sub

  
  

  Friday, December 13, 2019 6:18 AM
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  What do you mean by: "asking a function as a string"?
  
  - Wayne
  

  It doesn't seem like String(…, ...) should be there, but a value passed from somewhere else. Like Dim … As String = textbox1(…, ...).
  

  Friday, December 13, 2019 6:42 AM
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  I was able to refresh on some of the topics. Foolish, but I was looking at the example without applying values and I overlooked the foundations like making values equal to not get overflows. Simply, I didn't apply folders to pull the CSPs. I apologize for the lame question, but hence refreshing from one Lab in 2007. 

  Saturday, December 14, 2019 4:51 AM