VB.NET Structures and Union Help.

  • Thread starter Danny Mavromatis
  • Start date
D

Danny Mavromatis

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
 
H

Herfried K. Wagner [MVP]

Danny Mavromatis said:
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.
Click to expand...

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.
 
D

Danny Mavromatis

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
 
C

Cor Ligthert [MVP]

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
 
G

Guest

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*
 
D

Danny Mavromatis

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.
 
C

Cor Ligthert [MVP]

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
 
D

Danny Mavromatis

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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