FormattableSb 2.0.18

FormattableSb

A mutable FormattableString class:

List<DateTime> summerDates = GetSummerDates();

FormattableStringBuilder sqlBuilder = new FormattableStringBuilder()
    .AppendInterpolated($"INSERT INTO dbo.VacationDates (Date)")
    .AppendLine()
    .AppendInterpolated($"VALUES ({summerDates.First()})");

foreach (DateTime date in summerDates.Skip(1))
{
    sqlBuilder
        .AppendInterpolated($",")
        .AppendLine()
        .AppendInterpolated($"({date})");
}

// sql.Format:
// INSERT INTO dbo.VacationDates (Date)
// VALUES ({0}),
// ({1}),
// ({2}),
// ...

// sql.GetArguments():
// [
//   System.DateTime,
//   System.DateTime,
//   System.DateTime,
//   ...
// ]
FormattableString sql = sqlBuilder.ToFormattableString();

static List<DateTime> GetSummerDates()
{
    DateTime startDate = new(2040, 6, 20);
    DateTime endDate = new(2040, 9, 22);

    List<DateTime> dates = new();

    for (DateTime date = startDate; date <= endDate; date = date.AddDays(1))
    {
        dates.Add(date);
    }

    return dates;
}

With EF Core:

using VacationingContext context = new();
int rowsAffected = context.Database.ExecuteSql(sql);

Features:

• Adheres to the C# language specification
• Can be used when you want to modify a FormattableString
• Preserves alignment and format strings

API:

AppendInterpolated:

/// <summary>
/// Appends the specified interpolated string to the end of the composite format string,
/// replacing its arguments with placeholders and adding them as objects.
/// </summary>
/// <param name="handler">The interpolated string to append, along with the arguments.</param>
/// <returns>A reference to this instance after the append operation has completed.</returns>
public FormattableStringBuilder AppendInterpolated([InterpolatedStringHandlerArgument("")] ref AppendInterpolatedHandler handler)

AppendLine:

/// <summary>
/// Appends the default line terminator to the end of the composite format string.
/// </summary>
/// <returns>A reference to this instance after the append operation has completed.</returns>
public FormattableStringBuilder AppendLine()

AppendInterpolatedLine:

/// <summary>
/// Appends the specified interpolated string followed by the default line terminator
/// to the end of the composite format string, replacing its arguments with placeholders
/// and adding them as objects.
/// </summary>
/// <param name="handler">The interpolated string to append, along with the arguments.</param>
/// <returns>A reference to this instance after the append operation has completed.</returns>
public FormattableStringBuilder AppendInterpolatedLine([InterpolatedStringHandlerArgument("")] ref AppendInterpolatedHandler handler)

ToFormattableString:

/// <summary>
/// Creates a <see cref="FormattableString"/> from this builder.
/// </summary>
/// <returns>The object that represents the composite format string and its arguments.</returns>
public FormattableString ToFormattableString()

Setup:

• Install FormattableSb via NuGet Package Manager, Package Manager Console or dotnet CLI:

Install-Package FormattableSb

dotnet add package FormattableSb

Credits:

• Thanks to Stephen Toub for the implementation