UDF (User-Defined Functions)

DVDAddin provides ~70 custom Excel functions — used like normal Excel formulas (=DvdSum(A1:A10)).

How to use

In any cell, type = + function name + arguments:

=DvdNumToText(1234567)           → "Một triệu hai trăm ba mươi tư nghìn năm trăm sáu mươi bảy"
=DvdDateLunar(A1)                → "15/04/Ất Tỵ" (solar → lunar)
=DvdSpillRows(A1:C100, "Hanoi") → dynamic spill array of matching rows

All functions start with Dvd prefix (e.g. DvdSum, DvdLookup, DvdNumToText) — ensures no naming conflict with Excel built-ins.

Categories

Text (DvdTextFunctions.cs)

Function	Description
DvdUpper, DvdLower, DvdProper	Upper / lower / proper case — Vietnamese diacritics support (unlike UPPER built-in).
DvdRemoveDiacritics(text)	Strip Vietnamese diacritics: "Hà Nội" → "Ha Noi".
DvdJoin(range, separator)	Concat cells with separator (improved TEXTJOIN).
DvdRegexMatch(text, pattern)	True if text matches regex.
DvdRegexReplace(text, pattern, replacement)	Replace with regex.
DvdExtractNumbers(text)	Extract numbers from text.
DvdReverseText(text)	Reverse string.
DvdRomanToArabic(roman)	"MMXXVI" → 2026.
DvdArabicToRoman(num)	2026 → "MMXXVI".

Money + Math (DvdMoneyAndMath.cs)

Function	Description
DvdNumToText(num)	1234 → "Một nghìn hai trăm ba mươi tư đồng".
DvdNumToTextEN(num)	1234 → "One thousand two hundred thirty four".
DvdRound(value, mode)	Round with mode "up", "down", "nearest", "banker".
DvdFormatVnd(num)	1234567 → "1.234.567 đ".
DvdFormatUsd(num)	1234.56 → "$1,234.56".

Date/Time (DvdDateTimeFunctions.cs)

Function	Description
DvdWorkdays(start, end, holidays)	Working days (excluding Sat, Sun, holidays).
DvdAddWorkdays(start, days, holidays)	Add N working days.
DvdMonthDiff(start, end)	Months between 2 dates.

Lunar Calendar (DvdLunarCalendar.cs)

Function	Description
DvdToLunar(date)	Solar → lunar: "15/04/Ất Tỵ".
DvdToSolar(lunarDate)	Lunar → solar.

Range (DvdRangeFunctions.cs)

Function	Description
DvdSumVisible(range)	Sum VISIBLE cells (post-AutoFilter), unlike SUM.
DvdCountVisible(range)	Count visible cells.
DvdLastNonEmpty(range)	Last non-empty cell.
DvdFirstNonEmpty(range)	First non-empty cell.
DvdMaxByDate(rangeData, rangeDate)	Get value at max date.

Lookup (DvdLookupFunctions.cs)

Function	Description
DvdVLookupAll(needle, range, col)	Return all matches (unlike VLOOKUP first only).
DvdXLookup2D(rowKey, colKey, table)	2D XLOOKUP.
DvdRangeByName(name)	Get range by Named Range.

Spill (dynamic arrays) (DvdSpillFunctions.cs)

Function	Description
DvdSpillFilter(range, condition)	Filter rows matching condition → spill.
DvdSpillUnique(range)	Unique values (unlike UNIQUE built-in, multi-column).
DvdSpillSort(range, col, asc)	Sort spill.

Shape (DvdShapeFunctions.cs)

Function	Description
DvdShapeText(shapeName)	Text inside shape.
DvdShapeFillColor(shapeName)	Fill color of shape (hex).
DvdShapePosition(shapeName, prop)	Get Top/Left/Width/Height.

Network (DvdNetworkFunctions.cs)

Function	Description
DvdHttpGet(url)	GET request, returns body text.
DvdParseJson(text, path)	Read JSON field by dotted path.

AI (DvdAIFunctions.cs)

Function	Description
DvdAskGemini(prompt)	Ask Gemini, return text. Cell-level AI assistant.

Explain (DvdExplainFunctions.cs)

Function	Description
DvdExplain(cell)	AI explains formula in cell.
DvdExplainEN(cell)	English version.

Auto-Hide / Auto-Show (DvdAutoHide.cs)

Function	Description
DvdAutoHideRows(condition)	Hide/show rows by condition (volatile).

Translate

Function	Description
DvdTranslateGoogle(text, from, to)	Translate via free Google.
DvdTranslateGemini(text, from, to)	Translate via Gemini (needs API key).
DvdTranslateChatGPT(text, from, to)	Translate via OpenAI/Groq/Cerebras.

OCR (OcrLegacy.cs)

Function	Description
DvdOcr(filePath)	OCR image file → text.
DvdOcrPdf(pdfPath, page)	OCR one PDF page.

Notes

Volatile functions

Some functions are volatile — Excel recalculates them every time ANY cell changes. Volatile functions:

• DvdAutoHideRows
• DvdHttpGet (if URL contains {{timestamp}})

Volatile functions slow down workbooks. Avoid using in large quantity (>100 cells).

Async behavior

Network-calling functions (DvdHttpGet, DvdAskGemini, DvdTranslate*, DvdOcr*) run async — return #GETTING_DATA immediately → resolve when response arrives.

If a workbook has many async UDFs, you can limit concurrency to avoid rate limits:

• DvdTranslate* uses SemaphoreSlim(10) — max 10 parallel requests.
• DvdHttpGet no limit.

License gating

Function	Free	Activated/Trial
Text/number/date functions (local-only)	✓	✓
DvdTranslateGoogle	✓	✓
DvdTranslateGemini, DvdTranslateChatGPT, DvdAskGemini, DvdExplain*, DvdOcr*	✗ (returns #LICENSE!)	✓

Sample workbook

DVD Addin → ribbon → Sample Forms → opens demo file with all UDFs.

Related

• AI Assistant — interactive AI dialog (not UDF).
• Translate — translate dialog (not UDF).