Class VBUserDefinedTypeImage

Namespace

RDCore.SDK.Model.Types

Assembly

RDCore.SDK.dll

The bytes a VBUserDefinedTypeValue occupies in memory, laid out by VBUserDefinedTypeLayout — what an LSet between two UDT variables copies (MS-VBAL §5.4.3.6).

public static class VBUserDefinedTypeImage

Inheritance

object

VBUserDefinedTypeImage

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

The specification says twice that this is implementation-defined: "the data in expression (as stored in memory in an implementation-defined manner) is copied into bound-variable-expression in an implementation-defined manner". What it does not say, and what every VBA program using LSet on a UDT relies on, is that the copy reinterprets: the source's bytes are laid out by the source's own type and read back through the destination's, which is how VBA fakes a union. So this is a byte image and not a field-by-field assignment — between two UDTs of the same shape the two would agree, and between different shapes only the byte image does what the program meant.

👉 These are memory widths, the ones LenB counts. They are not the widths the same value takes in a record: VBUserDefinedTypeLayout's own remarks say why the two differ, and RecordDataFormat is the other one.

Methods

Copy(VBUserDefinedTypeValue, VBUserDefinedTypeValue)

Copies source into destination as bytes (MS-VBAL §5.4.3.6), reinterpreting them through the destination's own layout.

public static void Copy(VBUserDefinedTypeValue source, VBUserDefinedTypeValue destination)

Parameters

source VBUserDefinedTypeValue

The value read.

destination VBUserDefinedTypeValue

The value written, field by field, in place.

Remarks

Only the bytes both types have are copied, as a copy between records of different sizes must be: a destination field that does not fit entirely inside the source's image is left at its declared type's default rather than being filled with half a value.

HoldsVariableLengthString(VBUserDefinedType)

Whether type has a variable-length String member, directly or in a user-defined type that it has as a member.

public static bool HoldsVariableLengthString(VBUserDefinedType type)

Parameters

type VBUserDefinedType

The user-defined type to look into.

Returns

bool

Remarks

A fixed-length String member is not one: its characters are in the record. A variable-length one is a pointer, and it is what makes a byte copy of the record (LSet, MS-VBAL §5.4.3.6) unsafe in MS-VBA.

Of(VBUserDefinedTypeValue)

The memory image of value: each field's bytes at the offset its layout assigns, and zeroes in the padding between them.

public static byte[] Of(VBUserDefinedTypeValue value)

Parameters

value VBUserDefinedTypeValue

The value to lay out.

Returns

byte[]

Remarks

A field with no byte representation of its own — a variable-length String, an object, an array, a Variant — is a pointer in memory, and a pointer's bytes mean nothing to a process that did not allocate them. Those bytes are left zero here and the values are carried across by Copy(VBUserDefinedTypeValue, VBUserDefinedTypeValue) instead, which is the one place the reinterpretation can be done safely.