appsettings.json 的array 改成整串換掉。

ArrayReplacingJsonConfigurationSource.cs

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Configuration.Json;

public class ArrayReplacingJsonConfigurationSource : JsonConfigurationSource
{
    public override IConfigurationProvider Build(IConfigurationBuilder builder)
    {
        EnsureDefaults(builder);
        return new ArrayReplacingJsonConfigurationProvider(this);
    }
}

public class ArrayReplacingJsonConfigurationProvider : JsonConfigurationProvider
{
    private readonly HashSet<string> _arrayPrefixes =
        new(StringComparer.OrdinalIgnoreCase);

    public ArrayReplacingJsonConfigurationProvider(
        ArrayReplacingJsonConfigurationSource source) : base(source) { }

    public override void Load(Stream stream)
    {
        base.Load(stream);

        _arrayPrefixes.Clear();

        foreach (var key in Data.Keys)
        {
            var segments = key.Split(ConfigurationPath.KeyDelimiter);
            for (var i = 0; i < segments.Length; i++)
            {
                if (!int.TryParse(segments[i], out _)) continue;

                // 抽出數字 segment 之前的 prefix，例如：
                // "Serilog:WriteTo:0:Name" => "Serilog:WriteTo"
                // "Items:0" => "Items"
                if (i > 0)
                {
                    _arrayPrefixes.Add(
                        string.Join(ConfigurationPath.KeyDelimiter, segments.Take(i)));
                }

                break;
            }
        }
    }

    public override IEnumerable<string> GetChildKeys(
        IEnumerable<string> earlierKeys, string? parentPath)
    {
        // 若此路徑的陣列在當前檔案有重新定義，略過所有舊 key 達成整組替換
        if (parentPath is not null && _arrayPrefixes.Contains(parentPath))
            return base.GetChildKeys([], parentPath);

        return base.GetChildKeys(earlierKeys, parentPath);
    }
}

public static class ArrayReplacingConfigurationExtensions
{
    public static IConfigurationBuilder AddArrayReplacingJsonFile(
        this IConfigurationBuilder builder,
        string path,
        bool optional = false,
        bool reloadOnChange = false)
    {
        return builder.Add(new ArrayReplacingJsonConfigurationSource
        {
            Path = path,
            Optional = optional,
            ReloadOnChange = reloadOnChange
        });
    }
}

.NET 7 之後，目前是對照index 替換，ex ["A", "B"] ["C"] 會變成 ["C", "B"]
但這樣太不直覺，只好自己寫個改成整串換掉。