| name | devexpress-office-file-api-unit-conversion |
| description | Build .NET applications with the DevExpress Unit Conversion API for converting between metric and US units of measurement with type-safe fluent syntax. Use when converting distances, lengths, weights, temperatures, areas, volumes, speeds, or metric prefixes in .NET applications. Also use when someone mentions "DevExpress Unit Conversion", "UnitConversion", "DevExpress.UnitConversion", "convert units C#", "metric to imperial", "length conversion .NET", or asks about any unit conversion with DevExpress. Covers both .NET and .NET Framework. |
| metadata | {"author":"DevExpress","version":26.1,"source-commit":"12dab7a5b121db6eefabc59e4e6982bb5d1c35da"} |
DevExpress Unit Conversion API
A lightweight .NET library for converting between metric and US customary units of measurement using a type-safe fluent API. Supports distance, mass, temperature, area, volume, speed, and metric prefix conversions. The API requires no external dependencies beyond the DevExpress.Document.Processor NuGet package and works identically on .NET 6+ and .NET Framework 4.6.2+.
When to Use This Skill
Use this skill when you need to:
- Convert distances or lengths (meters, feet, miles, kilometers, inches, yards, nautical miles)
- Convert mass/weight values (grams, kilograms, pounds, ounces, metric tons)
- Convert temperatures (Celsius, Fahrenheit, Kelvin)
- Convert area measurements (square meters, square feet, acres, hectares, square miles)
- Convert volumes (liters, gallons, cubic meters, cubic feet, fluid ounces, pints, quarts)
- Convert speeds (km/h, m/s, mph, knots, feet per second)
- Convert between metric prefixes (kilo, mega, milli, micro, etc.)
- Combine unit values with arithmetic (e.g., 5 feet + 4 inches, then convert to meters)
- Build type-safe unit-aware calculations without manual conversion factors
Prerequisites & Installation
NuGet Packages
| Package | Purpose |
|---|
DevExpress.Document.Processor | Unit Conversion API (included in the package) |
.NET (6/7/8+)
dotnet add package DevExpress.Document.Processor
.NET Framework (4.6.2+)
Install-Package DevExpress.Document.Processor
Or add a direct reference to DevExpress.Docs.v25.2.dll.
Important: All DevExpress packages in a project must share the same version number. A valid DevExpress license is required.
Before You Start — Ask the Developer
Before generating code, ask these questions to avoid rework:
General Questions
- Target framework: Are you using .NET 8+, .NET 6/7, or .NET Framework 4.x?
- New or existing project?: Creating new or adding to existing?
- Hosting model: Console app, ASP.NET Core, Blazor, MAUI, WinForms, or something else?
Unit Conversion-Specific Questions
- Measurement category: Which category? (length / weight / temperature / area / volume / speed / metric prefix)
- Conversion direction: Metric to US, US to metric, between metric prefixes, or both directions?
Rule: If the developer's answer is ambiguous or missing, ask before generating code. Do not guess.
Component Overview
The Unit Conversion API provides two usage patterns:
- Fluent extension methods on numeric types (
double, int, float) — create a QuantityValue<T>, then call To{Unit}() to convert. QuantityValue<T> implicitly converts to double, so you can use it directly in arithmetic or string formatting.
- Static converter classes accessed via
Units.* — call .Convert(value, fromUnit, toUnit) for direct scalar conversion without creating QuantityValue<T> objects.
Key classes:
QuantityValue<T> (struct) — holds a value in a specific unit. Supports +, -, *, / operators. Implicitly converts to double.
Units (static class) — entry point for converter instances: Units.Distance, Units.Mass, Units.Temperature, Units.Area, Units.Volume, Units.Speed, Units.Metric.
Distance, Mass, Temperature, Area, Volume, Speed, MetricPrefix — enums listing available unit values for each category.
DistanceUnitsConverter, MassUnitsConverter, etc. — converter classes returned by Units.* properties.
Core Entry Point — Fluent API
using DevExpress.UnitConversion;
QuantityValue<Distance> height = (5.0).Feet() + (4.0).Inches();
double meters = height.ToMeters().Value;
double meters2 = height.ToMeters();
Console.WriteLine($"Height: {meters:F3} m");
Core Entry Point — Units.Convert() API
using DevExpress.UnitConversion;
double result = Units.Distance.Convert(100.0, Distance.Foot, Distance.Meter);
double fahrenheit = Units.Temperature.Convert(100.0, Temperature.Celsius, Temperature.Fahrenheit);
double meters = Units.Metric.Convert(5.0, MetricPrefix.Kilo, MetricPrefix.None);
Documentation & Navigation Guide
Getting Started
Refer to references/getting-started.md
When you need to:
- Install the NuGet package and set up the namespace
- Perform your first conversion (distance, weight, temperature)
- Understand both fluent and
Units.Convert() patterns
- See all measurement categories with one example each
- Combine values with arithmetic operators
Quick Start Example
using DevExpress.UnitConversion;
QuantityValue<Distance> height = (5.0).Feet() + (11.0).Inches();
Console.WriteLine($"Height: {height.ToMeters().Value:F3} m ({height.ToCentimeters().Value:F1} cm)");
QuantityValue<Mass> weight = (180.0).Pounds();
Console.WriteLine($"Weight: {weight.ToKilograms().Value:F2} kg");
QuantityValue<Temperature> bodyTemp = (98.6).Fahrenheit();
Console.WriteLine($"Body temp: {bodyTemp.ToCelsius().Value:F1}°C / {bodyTemp.ToKelvin().Value:F2} K");
QuantityValue<Area> room = (25.0).SquareMeters();
Console.WriteLine($"25 m² = {room.ToSquareFeet().Value:F2} ft²");
double mph = Units.Speed.Convert(30.0, Speed.MetersPerSecond, Speed.MilesPerHour);
Console.WriteLine($"30 m/s = {mph:F2} mph");
double mega = Units.Metric.Convert(5.0, MetricPrefix.Kilo, MetricPrefix.Mega);
Console.WriteLine($"5 kilo = {mega} mega");
What This Does
Demonstrates the two API patterns: fluent extension methods returning QuantityValue<T> (distance, mass, temperature) and direct scalar conversion via Units.*.Convert() (speed, metric prefix). Both patterns work identically on .NET and .NET Framework.
Key Properties & API Surface
QuantityValue<T>
| Property/Operator | Type | Description |
|---|
Value | double | Numeric value in the current unit |
implicit double | double | Implicit conversion — use directly in math/strings |
+ / - | QuantityValue<T> | Add or subtract same-category quantities |
* / / | QuantityValue<T> | Multiply or divide by a scalar |
Units (static class)
| Property | Type | Description |
|---|
Units.Distance | DistanceUnitsConverter | Distance/length conversions |
Units.Mass | MassUnitsConverter | Mass/weight conversions |
Units.Temperature | TemperatureUnitsConverter | Temperature conversions |
Units.Area | AreaUnitsConverter | Area conversions |
Units.Volume | VolumeUnitsConverter | Volume conversions |
Units.Speed | SpeedUnitsConverter | Speed conversions |
Units.Metric | MetricUnitsConverter | Metric prefix conversions |
BaseUnitsConverter<T>.Convert()
double Convert(double value, T from, T to)
void Convert(double[] values, T from, T to)
Distance Enum Values (most common)
Distance.Meter, Distance.Foot, Distance.Inch, Distance.Yard, Distance.MileStatute, Distance.MileNautical, Distance.Kilometer (via MetricPrefix), Distance.Angstrom
Note: Kilometer is not a direct Distance enum value. Use the MetricPrefix converter or the .Kilometers() extension method which internally handles the prefix.
Area Enum Values
Area.SquareMeter, Area.SquareMile, Area.SquareMileNautical, Area.Hectare, Area.SquareFoot, Area.SquareInch, Area.SquareYard, Area.AcreInternational, Area.AcreStatute, Area.Are, Area.Morgen
IMPORTANT — Area.SquareKilometer does not exist in this enum.
To convert to or from square kilometers, convert via Area.SquareMeter first, then divide or multiply by 1,000,000:
double squareMeters = Units.Area.Convert(2.5, Area.SquareMile, Area.SquareMeter);
double squareKm = squareMeters / 1_000_000.0;
Console.WriteLine($"2.5 sq mi = {squareKm:F4} km²");
double sqMiles = Units.Area.Convert(10.0 * 1_000_000.0, Area.SquareMeter, Area.SquareMile);
Console.WriteLine($"10 km² = {sqMiles:F4} sq mi");
Mass Enum Values
Mass.Gram, Mass.Pound, Mass.Ounce, Mass.Ton, Mass.TonImperial, Mass.Stone, Mass.Slug
Note: Kilogram is not a direct Mass enum value in Units.Mass.Convert(). Use the fluent .Kilograms() extension method, or Units.Metric.Convert(value, MetricPrefix.None, MetricPrefix.Kilo) after getting grams.
Temperature Enum Values
Temperature.Celsius, Temperature.Fahrenheit, Temperature.Kelvin, Temperature.Rankine, Temperature.Reaumur
Speed Enum Values
Speed.MetersPerHour, Speed.MetersPerSecond, Speed.MilesPerHour, Speed.Knot, Speed.KnotAdmiralty
MetricPrefix Enum Values
MetricPrefix.Tera, MetricPrefix.Giga, MetricPrefix.Mega, MetricPrefix.Kilo, MetricPrefix.Hecto, MetricPrefix.Deca, MetricPrefix.None, MetricPrefix.Deci, MetricPrefix.Centi, MetricPrefix.Milli, MetricPrefix.Micro, MetricPrefix.Nano, MetricPrefix.Pico, MetricPrefix.Femto, MetricPrefix.Atto
Common Patterns
Fluent Conversion (simple)
double feet = (100.0).Meters().ToFeet().Value;
Console.WriteLine($"100 m = {feet:F2} ft");
Fluent Conversion (compound)
QuantityValue<Distance> height = (6.0).Feet() + (2.0).Inches();
Console.WriteLine($"6'2\" = {height.ToCentimeters().Value:F1} cm");
Direct Scalar Conversion
double f = Units.Temperature.Convert(100.0, Temperature.Celsius, Temperature.Fahrenheit);
Console.WriteLine($"100°C = {f:F1}°F");
Batch Array Conversion
double[] distances = { 1.0, 5.0, 10.0, 42.195 };
Units.Distance.Convert(distances, Distance.Meter, Distance.Foot);
Metric Prefix Conversion
QuantityValue<Pressure> pressure = (760.0).MmHg();
double pascals = pressure.ToPascals();
var prefixConverter = new MetricUnitsConverter();
double hPa = prefixConverter.Convert(pascals, MetricPrefix.None, MetricPrefix.Hecto);
Console.WriteLine($"760 mmHg = {hPa:F1} hPa");
Volume Conversion
double gallons = Units.Volume.Convert(10.0, Volume.Liter, Volume.Gallon);
Console.WriteLine($"10 L = {gallons:F3} US gallons");
Troubleshooting
| Symptom | Cause | Solution |
|---|
Compile error: type Weight not found | Wrong type name | The enum is Mass, not Weight. Use QuantityValue<Mass> and .Pounds(), .Grams() etc. |
Compile error: Distance.Kilometer not found | Enum member absent | Kilometer is not in the Distance enum. Use .Kilometers() extension method on a double instead. |
Compile error: Area.SquareKilometer not found | Enum member absent | SquareKilometer is not in the Area enum. Convert via Area.SquareMeter then divide/multiply by 1,000,000. |
| Ambiguous extension method invocation | Conflicting namespace | Ensure only using DevExpress.UnitConversion; is present; remove conflicting using directives |
| Incorrect conversion result | Wrong extension method | .Feet() creates US feet, .Meters() creates SI meters — double-check the method name |
| Build error: type not found | Package not installed | Run dotnet add package DevExpress.Document.Processor |
| License error at runtime | Missing DevExpress license | Register license per the DevExpress installation guide |
| Version mismatch error | Mixed DX package versions | All DevExpress packages must use the same version |
Cannot add Distance + Mass | Type mismatch | Only add/subtract QuantityValue<T> of the same T. Mix categories only after extracting .Value. |
Constraints & Rules
CRITICAL — follow these rules in every interaction:
- Build verification: After making changes, verify the project builds with
dotnet build. Check for errors before reporting success.
- NuGet packages: Use only
DevExpress.Document.Processor. Do not guess other package names.
- Namespace imports: Always include
using DevExpress.UnitConversion;. Never assume it exists.
- Version consistency: All DevExpress packages must use the same version. Do not mix.
- Correct enum name: The mass/weight category is
Mass (not Weight). QuantityValue<Mass>, not QuantityValue<Weight>.
- License: DevExpress requires a valid license. Remind the developer if they hit license-related build errors.
- No destructive changes: Preserve existing code structure. Only add or modify what is necessary.
- Framework detection: Check the project's .csproj for target framework. The API works on both .NET and .NET Framework with the same code.
- Type safety: Only use
+/- operators on QuantityValue<T> instances with the same T. Never mix categories.
Using DevExpress Documentation MCP
If the DxDocs MCP server is available, use it to supplement this skill:
- Search: Use
devexpress_docs_search with technology "Unit Conversion API" and your question.
- Fetch: Use
devexpress_docs_get_content with a documentation URL to get full article content.
When to use MCP vs. built-in references:
- Built-in references: Getting started, common patterns, supported categories, troubleshooting.
- MCP search: Full list of extension methods for less common units (pressure, energy, force, magnetism, information), version-specific changes, or uncommon features.
- Always MCP for: Exact extension method names for units not listed here (e.g., pressure units like
.MmHg(), .Pascals()).
Next Steps
Start with Getting Started to install the package and run your first conversion, then explore specific categories through the examples above.