Dictionary<string, long>无法序列化问题求助

你的问题出在System.Text.Json默认只序列化公共属性，不序列化公共字段，所以offer字段没有被纳入序列化范围，最终输出空的{}。

下面是两种可行的解决方法：

方法一：将字段改为属性（推荐） #

这是符合C#封装规范的做法，把offer字段改成带get/set的属性：

public class Offer_RPC
{
    /// <summary>
    /// this dictionary contains your requested additions ans substractions, in mojos.<br/>
    /// if you wan to offer an nft for example, use the launcher id such as <br/>
    /// "1": 1000000000000 (offer for 1 xch) <br/>
    /// "cc4138f8debe4fbedf26ccae0f965be19c67a49d525f1416c0749c3c865dxxx", -1 <br/>
    /// </summary>
    public Dictionary<string, long> offer { get; set; } = new Dictionary<string, long>();

    public override string ToString()
    {
        JsonSerializerOptions options = new JsonSerializerOptions();
        options.WriteIndented = false;
        options.DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingNull;
        return JsonSerializer.Serialize(this, options);
    }
}

方法二：配置序列化选项以包含字段 #

如果无法修改字段定义，可以在序列化时开启IncludeFields选项，让序列化器处理公共字段：

public override string ToString()
{
    JsonSerializerOptions options = new JsonSerializerOptions();
    options.WriteIndented = false;
    options.DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingNull;
    // 开启公共字段序列化
    options.IncludeFields = true;
    return JsonSerializer.Serialize(this, options);
}

测试时，两种方法都能正确输出包含offer键值对的JSON，比如：{"offer":{"1":1,"2":-1}}

内容的提问来源于stack exchange，提问作者julian bechtold