下面是一个使用微软System.Text.Json库的解决方案:

static string FormatJsonText(string jsonString)
{
    using var doc = JsonDocument.Parse(
        jsonString,
        new JsonDocumentOptions
        {
            AllowTrailingCommas = true
        }
    );
    MemoryStream memoryStream = new MemoryStream();
    using (
        var utf8JsonWriter = new Utf8JsonWriter(
            memoryStream,
            new JsonWriterOptions
            {
                Indented = true
            }
        )
    )
    {
        doc.WriteTo(utf8JsonWriter);
    }
    return new System.Text.UTF8Encoding()
        .GetString(memoryStream.ToArray());
}

Net Core App

var js = JsonSerializer.Serialize(obj, new JsonSerializerOptions {
             WriteIndented = true
         });

对于使用。net Core 3.1的UTF8编码的JSON文件，我最终能够使用基于微软的信息:https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json-how-to#utf8jsonreader-utf8jsonwriter-and-jsondocument的JsonDocument

string allLinesAsOneString = string.Empty;
string [] lines = File.ReadAllLines(filename, Encoding.UTF8);
foreach(var line in lines)
    allLinesAsOneString += line;

JsonDocument jd = JsonDocument.Parse(Encoding.UTF8.GetBytes(allLinesAsOneString));
var writer = new Utf8JsonWriter(Console.OpenStandardOutput(), new JsonWriterOptions
{
    Indented = true
});
JsonElement root = jd.RootElement;
if( root.ValueKind == JsonValueKind.Object )
{
    writer.WriteStartObject();
}
foreach (var jp in root.EnumerateObject())
    jp.WriteTo(writer);
writer.WriteEndObject();

writer.Flush();

你可以使用以下标准方法来获取格式化的Json

JsonReaderWriterFactory。CreateJsonWriter(流流，编码编码，bool ownsStream, bool缩进，字符串indentChars)

只设置"缩进==true"

试试这样的方法

    public readonly DataContractJsonSerializerSettings Settings = 
            new DataContractJsonSerializerSettings
            { UseSimpleDictionaryFormat = true };

    public void Keep<TValue>(TValue item, string path)
    {
        try
        {
            using (var stream = File.Open(path, FileMode.Create))
            {
                //var currentCulture = Thread.CurrentThread.CurrentCulture;
                //Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;

                try
                {
                    using (var writer = JsonReaderWriterFactory.CreateJsonWriter(
                        stream, Encoding.UTF8, true, true, "  "))
                    {
                        var serializer = new DataContractJsonSerializer(type, Settings);
                        serializer.WriteObject(writer, item);
                        writer.Flush();
                    }
                }
                catch (Exception exception)
                {
                    Debug.WriteLine(exception.ToString());
                }
                finally
                {
                    //Thread.CurrentThread.CurrentCulture = currentCulture;
                }
            }
        }
        catch (Exception exception)
        {
            Debug.WriteLine(exception.ToString());
        }
    }

注意线条

    var currentCulture = Thread.CurrentThread.CurrentCulture;
    Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;
    ....
    Thread.CurrentThread.CurrentCulture = currentCulture;

对于某些类型的xml序列化器，您应该使用InvariantCulture来避免在具有不同区域设置的计算机上反序列化期间出现异常。例如，double或DateTime的无效格式有时会导致错误。

在反序列化

    public TValue Revive<TValue>(string path, params object[] constructorArgs)
    {
        try
        {
            using (var stream = File.OpenRead(path))
            {
                //var currentCulture = Thread.CurrentThread.CurrentCulture;
                //Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;

                try
                {
                    var serializer = new DataContractJsonSerializer(type, Settings);
                    var item = (TValue) serializer.ReadObject(stream);
                    if (Equals(item, null)) throw new Exception();
                    return item;
                }
                catch (Exception exception)
                {
                    Debug.WriteLine(exception.ToString());
                    return (TValue) Activator.CreateInstance(type, constructorArgs);
                }
                finally
                {
                    //Thread.CurrentThread.CurrentCulture = currentCulture;
                }
            }
        }
        catch
        {
            return (TValue) Activator.CreateInstance(typeof (TValue), constructorArgs);
        }
    }

谢谢!

下面是一个使用微软System.Text.Json库的解决方案:

static string FormatJsonText(string jsonString)
{
    using var doc = JsonDocument.Parse(
        jsonString,
        new JsonDocumentOptions
        {
            AllowTrailingCommas = true
        }
    );
    MemoryStream memoryStream = new MemoryStream();
    using (
        var utf8JsonWriter = new Utf8JsonWriter(
            memoryStream,
            new JsonWriterOptions
            {
                Indented = true
            }
        )
    )
    {
        doc.WriteTo(utf8JsonWriter);
    }
    return new System.Text.UTF8Encoding()
        .GetString(memoryStream.ToArray());
}

2023年更新

对于那些问我如何使用c#在。net中获得格式化JSON并想要看到如何立即使用它的人和一行爱好者。以下是缩进的JSON字符串一行代码:

有两种知名的JSON格式化器或解析器可以序列化:

Newtonsoft Json。网版:

using Newtonsoft.Json;

var jsonString = JsonConvert.SerializeObject(yourObj, Formatting.Indented);

.Net 7版本:

using System.Text.Json;

var jsonString = JsonSerializer.Serialize(yourObj, new JsonSerializerOptions { WriteIndented = true });