StandardDropdowns 1.0.0

StandardDropdowns

A comprehensive .NET library providing standardized reference data for dropdown/select lists. Stop recreating the same dropdown data across projects—use StandardDropdowns for consistent, well-tested reference data.

Why StandardDropdowns?

How many times have you implemented a US States dropdown? Or a countries list? Or months of the year? StandardDropdowns eliminates this repetitive work by providing:

• ✅ Accurate, standardized data - ISO codes, official names, proper abbreviations
• ✅ Framework agnostic - Works with ASP.NET Core, Blazor, WinForms, WPF, MAUI, and more
• ✅ Zero dependencies - Pure .NET Standard 2.0 implementation
• ✅ Flexible API - Simple static access for common cases, builder pattern for customization
• ✅ Thread-safe & immutable - Safe for concurrent access
• ✅ Comprehensive test coverage - Battle-tested with extensive unit tests

Installation

Install via NuGet Package Manager:

dotnet add package StandardDropdowns

Or via Package Manager Console:

Install-Package StandardDropdowns

Quick Start

using StandardDropdowns;

// Get all 50 US states
var states = DropdownData.UsStates.States50;

// Get all countries
var countries = DropdownData.Countries.All;

// Get all months
var months = DropdownData.Months.All;

// Lookup specific items
var texas = DropdownData.UsStates.ByAbbreviation("TX");
var usa = DropdownData.Countries.ByAlpha2Code("US");
var january = DropdownData.Months.ByNumber(1);

Available Data Sets

StandardDropdowns provides the following reference data:

Geographic Data

• US States - 50 states, District of Columbia, and 5 territories
• Countries - 200+ countries with ISO 3166-1 codes, organized by continent

Temporal Data

• Months - 12 months with names, abbreviations, and numbers
• Days of Week - 7 days with multiple abbreviation formats

Personal/Demographic Data

• Prefixes/Titles - Mr., Mrs., Ms., Dr., Prof., Rev., etc. (9 options)
• Suffixes - Jr., Sr., PhD, MD, Esq., etc. (22 options across 3 categories)
• Gender - Configurable gender options
• Marital Status - Single, Married, Divorced, Widowed, Separated, Domestic Partnership

General Purpose Data

• Yes/No Options - Multiple presets (Basic, With N/A, With Unknown)

Usage Examples

US States

using StandardDropdowns;

// Get different state groupings
var states50 = DropdownData.UsStates.States50;           // Just the 50 states
var statesAndDC = DropdownData.UsStates.StatesAndDC;     // 50 states + DC
var territories = DropdownData.UsStates.Territories;      // US territories only
var all = DropdownData.UsStates.All;                     // Everything

// Lookup by abbreviation or name
var texas = DropdownData.UsStates.ByAbbreviation("TX");
var california = DropdownData.UsStates.ByName("California");

// Use with ASP.NET Core MVC
@Html.DropDownListFor(m => m.StateCode, 
    new SelectList(DropdownData.UsStates.States50, "Value", "Text"))

// Use with Blazor
<select @bind="selectedState">
    @foreach (var state in DropdownData.UsStates.States50)
    {
        <option value="@state.Value">@state.Text</option>
    }
</select>

// Custom builder
var customStates = DropdownData.UsStates.Builder()
    .IncludeDC()
    .IncludeTerritories()
    .Exclude("AS", "GU", "MP")  // Exclude specific territories
    .OrderByName()
    .Build();

Countries

using StandardDropdowns;

// Get all countries
var allCountries = DropdownData.Countries.All;

// Filter by continent
var europeanCountries = DropdownData.Countries.ByContinent("Europe");

// Lookup by different codes
var usa = DropdownData.Countries.ByAlpha2Code("US");        // By 2-letter code
var canada = DropdownData.Countries.ByAlpha3Code("CAN");    // By 3-letter code
var germany = DropdownData.Countries.ByNumericCode("276");  // By numeric code
var france = DropdownData.Countries.ByName("France");       // By name

// Custom builder - North American countries only
var northAmerica = DropdownData.Countries.Builder()
    .InContinent("North America")
    .OrderByName()
    .Build();

// European Union subset (example)
var euCountries = DropdownData.Countries.Builder()
    .Only("AT", "BE", "BG", "HR", "CY", "CZ", "DK", "EE", "FI", 
          "FR", "DE", "GR", "HU", "IE", "IT", "LV", "LT", "LU",
          "MT", "NL", "PL", "PT", "RO", "SK", "SI", "ES", "SE")
    .OrderByName()
    .Build();

Months and Days

using StandardDropdowns;

// Get all months
var months = DropdownData.Months.All;

// Lookup specific month
var january = DropdownData.Months.ByNumber(1);
var december = DropdownData.Months.ByName("December");
var feb = DropdownData.Months.ByAbbreviation("Feb");

// Get all days of the week
var days = DropdownData.Days.All;

// Lookup specific day
var monday = DropdownData.Days.ByNumber(1);  // 0 = Sunday, 1 = Monday, etc.
var friday = DropdownData.Days.ByName("Friday");
var sat = DropdownData.Days.ByAbbreviation("Sat");
var su = DropdownData.Days.ByShortAbbreviation("Su");

Prefixes and Suffixes

using StandardDropdowns;

// Get all prefix titles
var prefixes = DropdownData.PrefixTitles.All;

// Lookup specific prefix
var doctor = DropdownData.PrefixTitles.ByNumber(5);
var mr = DropdownData.PrefixTitles.ByAbbreviation("Mr.");

// Filter by category
var civilianOnly = DropdownData.PrefixTitles.Builder()
    .InCategory("Civilian")
    .Build();

// Get all suffixes
var suffixes = DropdownData.Suffixes.All;

// Filter by category
var academicDegrees = DropdownData.Suffixes.ByCategory("Academic");
var generational = DropdownData.Suffixes.ByCategory("Generational");

// Custom suffix list
var doctorates = DropdownData.Suffixes.Builder()
    .InCategory("Academic")
    .Only("7", "8", "9", "10")  // PhD, MD, DDS, EdD
    .OrderByName()
    .Build();

Gender and Marital Status

using StandardDropdowns;

// Get gender options
var genders = DropdownData.Genders.All;
var male = DropdownData.Genders.ByCode("M");

// Get marital statuses
var statuses = DropdownData.MaritalStatuses.All;
var married = DropdownData.MaritalStatuses.ByCode("M");
var single = DropdownData.MaritalStatuses.ByName("Single");

Yes/No Options

using StandardDropdowns;

// Get different yes/no presets
var basic = DropdownData.YesNo.Basic;              // Yes, No
var withNA = DropdownData.YesNo.WithNA;            // Yes, No, N/A
var withUnknown = DropdownData.YesNo.WithUnknown;  // Yes, No, Unknown

// Lookup specific option
var yes = DropdownData.YesNo.ByCode("Y");

// Custom builder
var customOptions = DropdownData.YesNo.Builder()
    .IncludeNA()
    .OrderByName()
    .Build();

The ISelectOption Interface

All models implement the ISelectOption interface, making them easy to use with any UI framework:

public interface ISelectOption
{
    string Value { get; }  // The value to submit (e.g., "TX", "US", "1")
    string Text { get; }   // The display text (e.g., "Texas", "United States", "January")
}

This means you can use any dropdown data with generic rendering code:

// Generic method that works with ANY dropdown data
public SelectList CreateSelectList<T>(IEnumerable<T> items) 
    where T : ISelectOption
{
    return new SelectList(items, "Value", "Text");
}

// Use it with any data type
var statesList = CreateSelectList(DropdownData.UsStates.States50);
var countriesList = CreateSelectList(DropdownData.Countries.All);
var monthsList = CreateSelectList(DropdownData.Months.All);

Builder Pattern

StandardDropdowns uses a powerful builder pattern for customization:

// Example: Custom state list for a registration form
var registrationStates = DropdownData.UsStates.Builder()
    .IncludeDC()                    // Include Washington DC
    .Exclude("AS", "GU", "MP", "VI") // Exclude some territories
    .OrderByName()                   // Sort alphabetically
    .Build();

// Example: Major countries for shipping
var shippingCountries = DropdownData.Countries.Builder()
    .Only("US", "CA", "MX", "GB", "FR", "DE", "AU", "JP")
    .OrderByName()
    .Build();

// Example: Academic suffixes only
var academicSuffixes = DropdownData.Suffixes.Builder()
    .InCategory("Academic")
    .ExcludeCategory("Professional")
    .OrderByName()
    .Build();

Common Builder Methods

All builders support these methods:

• Exclude(params string[] values) - Exclude specific items by value
• Only(params string[] values) - Include only specific items
• OrderByText() - Sort by display text (ascending)
• OrderByTextDescending() - Sort by display text (descending)
• OrderByValue() - Sort by value (ascending)
• OrderByValueDescending() - Sort by value (descending)
• Build() - Build the final read-only list

Category-specific builders have additional methods:

US States:

• IncludeDC() - Include District of Columbia
• IncludeTerritories() - Include US territories
• IncludeAll() - Include everything
• ExcludeStates() - Exclude the 50 states
• OrderByName(), OrderByAbbreviation() - Convenience methods

Countries:

• InContinent(params string[] continents) - Include specific continents
• ExcludeContinent(params string[] continents) - Exclude continents
• OrderByName(), OrderByCode() - Convenience methods

Prefixes/Suffixes:

• InCategory(params string[] categories) - Include specific categories
• ExcludeCategory(params string[] categories) - Exclude categories

Yes/No:

• InPreset(params string[] presets) - Include specific presets
• ExcludePreset(params string[] presets) - Exclude presets
• IncludeNA() - Include Yes, No, N/A
• IncludeUnknown() - Include Yes, No, Unknown

Framework Examples

ASP.NET Core MVC

// In your controller
public IActionResult Create()
{
    ViewBag.States = new SelectList(
        DropdownData.UsStates.States50, 
        "Value", 
        "Text"
    );
    return View();
}

// In your view
@Html.DropDownListFor(
    m => m.StateCode, 
    (SelectList)ViewBag.States,
    "Select a state...",
    new { @class = "form-control" }
)

Blazor

<InputSelect @bind-Value="model.CountryCode" class="form-control">
    <option value="">Select a country...</option>
    @foreach (var country in DropdownData.Countries.All)
    {
        <option value="@country.Value">@country.Text</option>
    }
</InputSelect>

WinForms

// Bind to a ComboBox
stateComboBox.DataSource = DropdownData.UsStates.States50.ToList();
stateComboBox.DisplayMember = "Text";
stateComboBox.ValueMember = "Value";

WPF

<ComboBox ItemsSource="{Binding States}" 
          DisplayMemberPath="Text" 
          SelectedValuePath="Value" 
          SelectedValue="{Binding SelectedState}" />

// In your ViewModel
public IEnumerable<StateInfo> States => DropdownData.UsStates.States50;

MAUI

<Picker Title="Select State" 
        ItemsSource="{Binding States}" 
        ItemDisplayBinding="{Binding Text}" 
        SelectedItem="{Binding SelectedState}" />

Data Accuracy

StandardDropdowns uses authoritative sources for all data:

• US States: Official USPS abbreviations and names
• Countries: ISO 3166-1 standard (alpha-2, alpha-3, and numeric codes)
• Months/Days: Standard calendar conventions
• Prefixes/Suffixes: Common professional and social conventions

All data is thoroughly tested with comprehensive unit test coverage.

Thread Safety

All data providers use lazy initialization and return immutable read-only collections, making them safe for concurrent access:

// Safe to call from multiple threads
Parallel.For(0, 100, i =>
{
    var states = DropdownData.UsStates.All;  // Thread-safe
    var texas = DropdownData.UsStates.ByAbbreviation("TX");  // Thread-safe
});

Requirements

• .NET Standard 2.0 - Compatible with:
  • .NET Framework 4.6.1+
  • .NET Core 2.0+
  • .NET 5, 6, 7, 8+
  • Xamarin
  • MAUI

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

Areas for contribution:

• Additional data sets (languages, currencies, time zones, etc.)
• Localization support
• Additional builder methods
• Bug fixes and improvements

License

This project is licensed under the MIT License - see the LICENSE.txt file for details.

Roadmap

Future versions may include:

• Additional Data Sets

  • Languages (ISO 639)
  • Currencies (ISO 4217)
  • Time zones
  • Canadian provinces
  • Mexican states
  • Industry classifications (NAICS)
  • Education levels
  • Phone/address types
  • Employment statuses
  • Company sizes
  • Payment methods

• Localization Support

  • Translated country/month names
  • Culture-specific formats

• Conversion Methods

  • Direct conversion to framework-specific types
  • Custom mapping support

Support

If you encounter any issues or have questions:

• 📝 Open an issue
• 💬 Start a discussion

Acknowledgments

Built with care to save developers time and ensure data consistency across .NET applications.

Made with ❤️ for the .NET community