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C# Problem translating Comm functions from VB.Net

Posted on 2012-12-30

1 solution

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Last Modified: 2012-12-30

The two enclosed proc works perfectly in VB2008 but I'm unable to translate them correctly to C#
If I am understanding well the doc I need to use "static" features but they don't compile.
I'm quite sure the error will be obvious to an expert !
Thanks for the help

Original VB2008 Code:

Public Function OpenCommPort(ByVal SaxComm As CommStudio.SaxComm, ByVal nCommPort As Integer) As Integer

        Dim vInput As Object

        If (SaxComm.PortOpen = True) Then
            If (SaxComm.CommPort = "COM" & CStr(nCommPort)) Then 'correct comm port already open
                OpenCommPort = nCommPort
                Exit Function
            Else 'port open, but wrong comm port
                SaxComm.PortOpen = False    'close the port before re-assigning CommPort
            End If
        End If

        SaxComm.CommPort = nCommPort    'can not re-assign unless comm port closed

        On Error Resume Next 'skip error messages from appearing
        SaxComm.PortOpen = True

        If (SaxComm.PortOpen = True) Then
            ' Comm Port open OK
            SaxComm.InputLen = 0
            vInput = SaxComm.Input  'Clear Buffer and reset count
        End If

        OpenCommPort = nCommPort

    End Function

    Private Sub RxOEMDF1()

        Static vInput As Object

        If blnInSync Then 'In-sync
            If vInput(SaxComm1.InBufferCount >= 3) Then
                SaxComm1.InputLen = 3 'get next 3 characters
                vInput = SaxComm1.Input
                nNoDataCtr = TB1_TWO_SEC

                ' put data in Byte array
                naByte(1) = vInput(0)
                naByte(2) = vInput(1)
                naByte(3) = vInput(2)

                ' test frame
                If ((naByte(1) >= &H80) And (naByte(2) < &H80) And (naByte(3) < &H80)) Then
                    ' Frame OK
                    nSpO2_Status = naByte(1) And &H7C
                    nFloatByte(1) = naByte(1) And &H3
                    nFloatByte(2) = naByte(2)
                    nFloatByte(3) = naByte(3)
                    blnNewFrame = True      ' signal New Frame
                    blnNewPacket = True     ' signal New Packet
                Else ' out of sync
                    blnInSync = False
                End If ' Frame test
            End If ' There was 3 characters

        Else ' Not-in-sync
            If vInput Then '(SaxComm1.InBufferCount >= 1) Then
                SaxComm1.InputLen = 1 'to get one character
                vInput = SaxComm1.Input 'get character
                nNoDataCtr = TB1_TWO_SEC

                ' shift byte into Byte array
                naByte(1) = naByte(2)
                naByte(2) = naByte(3)
                naByte(3) = vInput(0)

                ' test frame
                If ((naByte(1) >= &H80) And (naByte(2) < &H80) And (naByte(3) < &H80)) Then
                    ' Frame OK
                    nSpO2_Status = naByte(1) And &H7C
                    nFloatByte(1) = naByte(1) And &H3
                    nFloatByte(2) = naByte(2)
                    nFloatByte(3) = naByte(3)
                    blnInSync = True
                End If ' Frame OK
            End If ' There was a character

        End If ' Else Not-in-sync

    End Sub

Open in new window

My translated code

private void RxOEMDF1()
    {
        //In-sync
        if (blnInSync)
        {
           
            if SaxComm1.InBufferCount >= 3
            {
                SaxComm1.InputLen = 3;
                //get next 3 characters
                static_RxOEMDF1_vInput = SaxComm1.Input;
                nNoDataCtr = TB1_TWO_SEC;

                // put data in Byte array
                naByte(1) = static_RxOEMDF1_vInput(0);
                naByte(2) = static_RxOEMDF1_vInput(1);
                naByte(3) = static_RxOEMDF1_vInput(2);

                // test frame
                if (((naByte(1) >= 0x80) & (naByte(2) < 0x80) & (naByte(3) < 0x80)))
                {
                    // Frame OK
                    nSpO2_Status = naByte(1) & 0x7c;
                    nFloatByte(1) = naByte(1) & 0x3;
                    nFloatByte(2) = naByte(2);
                    nFloatByte(3) = naByte(3);
                    blnNewFrame = true;
                    
                    // signal New Frame
                    blnNewPacket = true;
                    
                    // signal New Packet
                    // out of sync
                }
                else
                {
                    blnInSync = false;
                }
                // Frame test
            }
            // There was 3 characters

            // Not-in-sync
        }
        else
        {
            (SaxComm1.InBufferCount >= 1) Then
            if (static_RxOEMDF1_vInput)
            {
                SaxComm1.InputLen = 1;
                //to get one character
                static_RxOEMDF1_vInput = SaxComm1.Input;
                //get character
                nNoDataCtr = TB1_TWO_SEC;

                // shift byte into Byte array
                naByte(1) = naByte(2);
                naByte(2) = naByte(3);
                naByte(3) = static_RxOEMDF1_vInput(0);

                // test frame
                if (((naByte(1) >= 0x80) & (naByte(2) < 0x80) & (naByte(3) < 0x80)))
                {
                    // Frame OK
                    nSpO2_Status = naByte(1) & 0x7c;
                    nFloatByte(1) = naByte(1) & 0x3;
                    nFloatByte(2) = naByte(2);
                    nFloatByte(3) = naByte(3);
                    blnInSync = true;
                }
                // Frame OK
            }
            // There was a character

        }
        // Else Not-in-sync

    }

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Comment

Question by:luciepaul

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6 Comments

LVL 9

Expert Comment

by:gt2847c

ID: 387313952012-12-30

One quick thing I see is that you're trying to address arrays with () rather than []. C# uses square brackets for arrays. Arrays are also numbered starting with zero rather than one. So the first element in an array is myArray[0], not myArray[1].

Also, static in C# means that the object does not need to be "new'd". With static objects and functions, they have no dynamic members so you can't have more than one of them at a time. (btw, this is a very oversimplified description and you should read more on the subject...)

I'll try and look through and see if anything else jumps out...

LVL 9

Expert Comment

by:gt2847c

ID: 387314232012-12-30

Other items I see:

Line 7 needs parenthesis around your if statement. You have:
if SaxComm1.InBufferCount >= 3
Should read
if ( if SaxComm1.InBufferCount >= 3 )

naByte does not appear to be declared anywhere, so I don't know what type it is or how large it is. And as stated in my previous comment, your references to naByte and nFloatByte should start at zero, for example:

                // put data in Byte array
                naByte[0] = static_RxOEMDF1_vInput[0];
                naByte[1] = static_RxOEMDF1_vInput[1];
                naByte[2] = static_RxOEMDF1_vInput[2];

Open in new window

Try those fixes and see what you get. Also, if you can include specific compiler errors, it may help determine what else needs to be worked on...

LVL 86

Expert Comment

by:Mike Tomlinson

ID: 387314542012-12-30

C# doesn't have a direct equivalent of VB's local, static variables. For C#, simply move the declaration of that variable from the method, out to class level.

Author Comment

by:luciepaul

ID: 387314942012-12-30

@gt2847c
After fixing what you suggest everything seems to compile now.
I'm just left with another faulty line :

In VS2008:
If (naByte(2) And &H1) Then

Translated to C#
if ((naByte[2] & 0x1)
gives an error message : "unable to convert implicitly int in bool"

LVL 9

Accepted Solution

by:gt2847c

gt2847c earned 500 total points

ID: 387315132012-12-30

C# does not do implicit int (zero/non-zero) conversions to boolean true/false like C and other languages did (forcing you into strong typing in use of booleans). You'll have to test explicitly what you're looking for. If you want a non-zero value to be true, you'll need to write your if statement like:

if(( naByte[2] & 0x1) == 0x1)

or

if(( naByte[2] & 0x1) != 0)

or

if(( naByte[2] & 0x1) > 0)

Whatever your preference is

Author Closing Comment

by:luciepaul

ID: 387315482012-12-30

Great help
Thank you

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