I have a chunk of VC.NET code (below) that I need to convert to VB.NET
syntax.  Could someone help me get started?  I'm new to structures and
unions and I don't understand how to nest then in VB.NET.

' ----- VC.NET CODE THAT I NEED TO CONVERT TO VB.NET ----

struct R_OMNI_LINK_MESSAGE {
  //unsigned char StartChar;
  unsigned char MessageLength;
  union {
    unsigned char Data[255];
    struct {
      unsigned char MessageType;
      union {
        struct /* olmNAME_DATA (8 bit) */ {
          unsigned char ItemType8;
          unsigned char ItemNumber8;
          unsigned char ItemName8[16];
        };
        struct /* olmNAME_DATA (16 bit) */ {
          unsigned char ItemType16;
          unsigned char ItemNumber16MSB;
          unsigned char ItemNumber16LSB;
          unsigned char ItemName16[16];
        };
        struct /* olmEVENT_LOG_DATA */ {
          unsigned char EventNumber;  // (1-N, With 1 Being Most Recent)
          unsigned char EventTimeDateValid;
          unsigned char EventMonth;  // (1-12)
          unsigned char EventDay;  // (1-31)
          unsigned char EventHour;  // (0-23)
          unsigned char EventMinute;  // (0-59)
          unsigned char EventType;
          unsigned char EventParameter1;
          unsigned char EventParameter2High;
          unsigned char EventParameter2Low;
        };
        struct /* olmCOMMAND_MESSAGE */ {
          unsigned char Command;
          unsigned char Parameter1;
          unsigned char Parameter2High;
          unsigned char Parameter2Low;
        };
        struct /* olmSET_TIME */ {
          unsigned char stYear;
          unsigned char stMonth;
          unsigned char stDay;
          unsigned char stDOW;
          unsigned char stHour;
          unsigned char stMinute;
          unsigned char stDST;
        };
        struct /* olmSYSTEM_INFORMATION */ {
          unsigned char ModelNumber;
          unsigned char MajorVersion;
          unsigned char MinorVersion;
          unsigned char Revision;
          unsigned char LocalPhoneNumber[25];
        };
        struct /* olmSYSTEM_STATUS */ {
          unsigned char TimeDateValidFlag;
          unsigned char Year;  // (0-99)
          unsigned char Month;  // (1-12)
          unsigned char Day;  // (1-31)
          unsigned char DayOfWeek;  // (1-7)
          unsigned char Hour;  // (0-23)
          unsigned char Minute;  // (0-59)
          unsigned char Second;  // (0-59)
          unsigned char DaylightSavingsTimeFlag;
          unsigned char CalculatedSunriseHour;  // (0-23)
          unsigned char CalculatedSunriseMinute;  // (0-59)
          unsigned char CalculatedSunsetHour;  // (0-23)
          unsigned char CalculatedSunsetMinute;  // (0-59)
          unsigned char BatteryReading;
          unsigned char AreaSecurityMode[8];  // index 0-7
          struct {
            unsigned char Status;
            unsigned char BatteryReading;
          } ExpansionEnclosure[8];  // index 0-7
        };
        struct /* olmREQUEST_ZONE_STATUS */ {
          unsigned char StartingZone;
          unsigned char EndingZone;
        };
        struct /* olmZONE_STATUS */ {
          unsigned char ZoneStatus;
          unsigned char AnalogLoopReading;
        } Zone[127];
        struct /* olmREQUEST_UNIT_STATUS (8 bit) */ {
          unsigned char StartingUnit;
          unsigned char EndingUnit;
        };
        struct /* olmREQUEST_UNIT_STATUS (16 bit) */ {
          unsigned char StartingUnitMSB;
          unsigned char StartingUnitLSB;
          unsigned char EndingUnitMSB;
          unsigned char EndingUnitLSB;
        };
        struct /* olmUNIT_STATUS */ {
          unsigned char CurrentCondition;
          unsigned char HighByteOfTime;
          unsigned char LowByteOfTime;
        } Unit[84];
        struct /* olmREQUEST_AUXILIARY_STATUS */ {
          unsigned char StartingTemperatureSensor;
          unsigned char EndingTemperatureSensor;
        };
        struct /* olmAUXILIARY_STATUS */ {
          unsigned char RelayStatus;
          unsigned char CurrentTemperature;
          unsigned char LowHeatTemperatureSetpoint;
          unsigned char HighCoolTemperatureSetpoint;
        } TempSensor[63];
        struct /* olmREQUEST_THERMOSTAT_STATUS */ {
          unsigned char StartingThermostat;
          unsigned char EndingThermostat;
        };
        struct /* olmTHERMOSTAT_STATUS */ {
          unsigned char StatusByte;
          unsigned char CurrentTemperature;
          unsigned char HeatSetpoint;
          unsigned char CoolSetpoint;
          unsigned char SystemMode;
          unsigned char FanMode;
          unsigned char HoldStatus;
        } Thermostat[36];
        struct /* olmLOGIN */ {
          unsigned char LoginCode1;
          unsigned char LoginCode2;
          unsigned char LoginCode3;
          unsigned char LoginCode4;
        };
        struct /* olmSYSTEM_EVENTS */ {
          unsigned char High;
          unsigned char Low;
        } SystemEvent[127];
        struct /* olmMESSAGE_STATUS */ {
          unsigned char Data;
        } MessageStatus[33];
        struct /* olmREQUEST_SECURITY_CODE_VALIDATION */ {
          unsigned char AreaNumber;  // (1-8)
          unsigned char Code1;  // First Digit Of Code
          unsigned char Code2;  // Second Digit Of Code
          unsigned char Code3;  // Third Digit Of Code
          unsigned char Code4;  // Fourth Digit Of Code
        };
        struct /* olmSECURITY_CODE_VALIDATION */ {
          unsigned char UserCodeNumber;  // (1-99, 251 for duress, 0 if
invalid)
          unsigned char AuthorityLevel;
//(0=Invalid,1=Master,2=Manager,3=User)
        };
      };  // union
    };  // struct
  }; // union
};

Thanks,
Danny

You can simulate unions using the 'FieldOffset' attribute as shown in the
sample at
<URL:http://dotnet.mvps.org/dotnet/faqs/?id=setscreenresolution&lang=en>.
VB.NET doesn't support unions in its syntax directly.

Herfried,

Thanks for the quick reply... however, looking at the example, I'm a bit
confused...

Lets say I have the following from VC.NET:

struct R_OMNI_LINK_MESSAGE {
  //unsigned char StartChar;
  unsigned char MessageLength;
  union {
    unsigned char Data[255];
    struct {
      unsigned char MessageType;
      union {
        struct /* olmNAME_DATA (8 bit) */ {
          unsigned char ItemType8;
          unsigned char ItemNumber8;
          unsigned char ItemName8[16];
        };
        struct /* olmNAME_DATA (16 bit) */ {
          unsigned char ItemType16;
          unsigned char ItemNumber16MSB;
          unsigned char ItemNumber16LSB;
          unsigned char ItemName16[16];
        };
      };  // union
    };  // struct
  }; // union
};


I would have the following in VB.NET???:

<StructLayout(LayoutKind.Explicit)> _
Private Structure R_OMNI_LINK_MESSAGE
    ' struct {
        <FieldOffset(0)> Public MessageLength As Integer
        <FieldOffset(2)> Public MessageType As Char
        <FieldOffset(4)> Public ItemType8 As Char
        <FieldOffset(6)> Public ItemNumber8 As Char
    ' }
End Structure


I'm not understanding the concept... could someone help me get started with
the code I have?  So I can visually see how to do it with my code.

Thanks,
Danny



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Danny,

You know that converting direct from one language to another gives forever
terrible code. The first time I saw this was in the Cobol Fortran battle
time.

Somebody usually writing Fortran had showed how much inefficient
instructions were needed to do a sort in Cobol, while he could done it clean
in Fortran.

He did not know that Sort is in Cobol one method.

Cor

Cor, you are showing your age;-)
its a bit like rewriting an 8080 block copy into Z80 instead of using the
intrinsic LDIR opcode. That dates me too lol

*guy*

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So are you guys saying it's not possible?  The reason why I need to convert
to VB.NET is because the provider of the DLL doesn't have an example for
VB.NET so, I'm trying to make it work with my application... everything else
I rewrote and is working... I'm just stuck on the unions and structures.
It's something that I haven't ever been exposed to in VB.NET.    So I was
asking for some help... I take it that it's more difficuilt to do unions and
structures in VB.net than it is writting a reply that doesn't really help,
otherwise, someone would have provided some example code with my example, to
help me on my way.



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Danny,

No that is not what we are writing. We try to tell you that it is better to
analyze your problem than to take a piece of code from a not related
development tool.

If you decribe your problem than it is problably in newsgroups like this
easier to help you. Mostly you find it than yourself by the way.

I hope this helps,

Cor

Umm, no, the reason why I posted is because I have exhaused my resources and
this is my last resort.

What I need help with is this:

I  have a record structure that comes in via WM_COPYDATA and  I grab the
cbData (length of response message) and lpData (ptr to response message).
This data must be copied to local variables so I can access the data outside
of the WM_COPYDATA function.  So, for ease of processing the cbData and
lpData, it can be moved into a R_OMNI_LINK_MESSAGE structure (which is the
where I'm stuck) where the fields can be referred to by name rather than
byte offset.

So, I'm trying to figure out a way to do this in VB.net... structures and
unions seem to make sense, since that is what they are designed for...
however, I don't know anything about them in VB.net... hence, me asking for
some help.

Danny

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Maybe this link will help:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconmarshalingclassesstructuresunions.asp

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FYI:   I've moved this discussion to another board where it's more helpful.

http://www.vbdotnetforums.com/showthread.php?p=23724#post23724



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