[RESOLVED] VB.net Code to C#

[wiss.dev]

Hi,
I'm trying to rewrite my code in c#, the one thing i missed is the equivalent to this

Public sControlPath As New String(" ", 256)

in c#, could this be causing it to error ?

Public Class vbCode
    Public sControlPath As New String(" ", 256)
    Public bIsAccess As Boolean = False
    Public sControlServer As New String(" ", 256)
    
    Public sSqlName As New String(" ", 31)
    Public sSqlPassword As New String(" ", 31)
    Public sError As New String(" ", 2049)
    Public bRet As Boolean


    Declare Function GetInfo Lib "ABC.dll" (ByVal sControlPath As String, _
    ByRef bIsAccess As Boolean, ByVal sControlServer As String, ByVal sSqlName As String, _
    ByVal sSqlPassword As String, ByVal sError As String) As Boolean

    
    Sub New()
        bRet = GetInfo(sControlPath, bIsAccess, sControlServer, sSqlName, sSqlPassword, sError)
     
    End Sub

End Class

C#

public class cSharpCode
        {
            [DllImport("ABC.dll")]
            private static extern bool GetInfo(string cControlPath,ref bool bIsAccess,string cControlServer, string sSqlName, string sSqlPassword,string sError);
                 
          
         
            public string sControlPath;
            public bool bIsAccess,bRet;
            public string sControlServer, sSqlName, sSqlPassword, sError;

            public cSharpCode()
            {
                       
               
                bRet = GetInfo(sControlPath, ref bIsAccess, sControlServer, sSqlName, sSqlPassword, sError);
                

             
            }
           
    
    }

Errors on calling GetInfo() in cSharpCode constructor : Attempted to write or read protected memory, this is often an indication that the other memory is corrupt.

[Toph]

Try using
http://converter.telerik.com/

and report if you have any errors?

[.paul.]

yes it would cause an error, as in vb you pass a string of spaces, that getinfo returns as a string of chars, probably null terminated...

[techgnome]

At first I thought it was because you didn't define the size of the string buffers, which you like this:

String controlPath;
controlPath = new String(' ', 256);

But then I realized the strings are byVal, so it shouldn't matter... shouldn't but doesn't mean it doesn't.
My guess is that it's looking for strings of a specific size (otherwise why have the fixed-length strings in VB) and it's not getting it.
Try setting each string to a specific size, then fill it with the data you need (treat it like an array of characters - or use some kind calculation to figure it all in) to pass it into the function and see if that helps.

-tg

[techgnome]

yes it would cause an error, as in vb you pass a string of spaces, that getinfo returns as a string of chars, probably null terminated...

Returns? or accepts? the definition looks like it returns a boolean to me...
But yeah, I think you're on the right idea there. the strings need to be padded with spaces to the proper length.

-tg

[wiss.dev]

Thanks guys, this did the trick

  public string sControlPath = new string(Convert.ToChar(" "), 256);

[David Anton]

Thanks guys, this did the trick

  public string sControlPath = new string(Convert.ToChar(" "), 256);

You can do this more directly:

public string sControlPath = new string(' ', 256);

[jmcilhinney]

You can do this more directly:

public string sControlPath = new string(' ', 256);

Quite right. The main issue here is that it was bad VB code to start with. That String constructor expects a Char and you were passing a String. That String was being implicitly converted to a Char by taking the first character of the String. You obviously have Option Strict Off or that code wouldn't even compile, which means it's bad code as far as I'm concerned.

If you're going to convert VB code to C# and you don't already have Option Strict On (for which there's no real excuse) then the first thing to do is turn it On and fix all the errors that get flagged. At least you then have a level playing field, i.e. the VB compiler will play by basically the same rules rules as the C# compiler with regards to strict typing. If you'd been using a Char in VB then an online converter probably would have had no issues.

[wiss.dev]

about to start pulling my hair now

for no reason that i know, my c# code no longer populate the variables, it is fine in VB though

Option Strict On
Public Class vb

    dim sControlPath As New String(Convert.ToChar(" "), 256)
    Public bIsAccess As Boolean = False
    Dim sControlServer As New String(Convert.ToChar(" "), 256)
   
    Dim sSqlName As New String(Convert.ToChar(" "), 31)
    Dim sSqlPassword As New String(Convert.ToChar(" "), 31)
    Dim sError As New String(Convert.ToChar(" "), 2049)
    Dim bRet As Boolean




    Declare Function GetInfo Lib "ABC.dll" (ByVal sControlPath As String, _
    ByRef bIsAccess As Boolean, ByVal sControlServer As String, ByVal sSqlName As String, _
    ByVal sSqlPassword As String, ByVal sError As String) As Boolean
   


    Sub New()
        bRet = GetInfo(sControlPath, bIsAccess, sControlServer, sSqlName, sSqlPassword, sError)
       
    End Sub

End Class

Here GetInfo returns true, fields are not changed

public class cSharp
        {
            bool bIsAccess, bRet;
            string sControlServer = new string(Convert.ToChar(" "), 256);
            string sSqlName = new string(Convert.ToChar(" "), 31);
            string sSqlPassword = new string(Convert.ToChar(" "), 31);
            string sError = new string(Convert.ToChar(" "), 2049);
            string sControlPath = new string(Convert.ToChar(" "), 256);

            [DllImport("ABC.dll")]
            private static extern bool GetInfo(string sControlPath, ref bool bIsAccess, string sControlServer, string sSqlName, string sSqlPassword, string sError);          
           

            public cSharp()
            {
                bRet = GetInfo(sControlPath, ref bIsAccess, sControlServer, sSqlName, sSqlPassword, sError);
              
              
            }
    
        }

[techgnome]

Well, bIsAccess may (or may not) change... wouldn't expect the others to though... you're passing them (C# equivelent of) by val.

-tg