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This page lists some solutions to common MicroStation VBA (MVBA) problems. Tips are published as examples and are not necessarily working code.

Introduction

Each and every element in a a DGN file has a unique Element ID. The ID is a 64-bit integer number. A MicroStation user has little reason to know of the ID, but it's visible in the Element Information dialog …

The Element ID is shown in the Raw Data region near the bottom of that dialog.

VBA Element ID

MicroStation CONNECT

VBA for MicroStation CONNECT continues to support the DLong data type so that legacy VBA applications don't break. However, since MicroStation CONNECT is a 64-bit application, so also is VBA. The VBA in MicroStation CONNECT is VBA version 7.1, as implemented by Microsoft in its 64-bit Office applications.

In particular, VBA 7.1 introduces the LongLong data type, which is a 64-bit integer. You can use a variable having that data type to store an element ID …

    Dim oElement                            As Element
    Set oElement = ... get element from somewhere
    Dim id                                  As LongLong
    id = oElement.ID64
    Debug.Print "Element ID=" & CStr(id)

MicroStation V8

Using VBA you can obtain an element's Element ID using the Element.ID method. The ID is returned in a DLong user defined type (UDT).

    Dim oElement                            As Element
    Set oElement = ... get element from somewhere
    Dim id                                  As DLong
    id = oElement.ID
    Debug.Print "Element ID=" & DLongToString (id)

DLong User Defined Type

Bentley Systems developed MicroStation VBA from Microsoft's VBA Toolkit. VBA is an elderly technology, corresponding to Visual Basic (VB) 5½. MicroStation V8 delivers 32-bit VBA technology, which does not comprehend or support 64-bit numbers.

To solve that lack of support for 64-bit numbers in the VBA Toolkit, Bentley Systems invented the DLong user defined type (UDT) and a handful of functions to deal with it. A DLong packs two 32-bit numbers into that UDT.

You should not concern yourself with the .Low and .High components. Always treat a DLong, and hence an Element.ID, as if it were a single number. If you search VBA help for DLong you will find the functions that let you compare DLongs, convert a DLong to a DLongString, assign a value to a DLong, and a few more.

DLong Function Family

Function	Description
DLongToLong	Converts a DLong to a Long
DLongFromLong	Converts a Long to a DLong
DLongToString	Converts a DLong to a String
DLongFromString	Converts a String to a DLong
DLongToHexString	Converts a DLong to a String in hexadecimal format
DLongFromHexString	Converts a String in hexadecimal format to a DLong
DLongFromDouble	Converts a Double to a DLong
DLongComp	Compares two DLongs
DLongAdd	Calculates the sum of two DLongs
DLongSubtract	Calculates the difference between two DLongss
DLongMultiply	Calculates the product of two DLongs
DLongDivide	Calculates the quotient of two DLongs
DLongMode	Calculates the modulus (remainder after division)
DLongNegate	Reverses the sign of a DLong
DLongAbs	Calculates the absolute value of a DLong

Notes for C++ and C# Developers

MicroStation V8i VBA requires the DLong user defined type because it can't provide 64-bit integers. When VBA was invented, it had nothing bigger than a 32-bit (Long) integer . MicroStation CONNECT delivers 64-bit VBA, which does provide 64-bit (LongLong) integers.

C++

Visual C++ provides the __int64 data type, which matches perfectly MDL's mdlElement_getID function. The MDL header files provide the typedef or alias ElementID for __int64.

.NET

.NET understands 64-bit integers. C#, for example, has the Int64 data type.

Questions

Post questions about MicroStation programming to the MicroStation Programming Forum.