I'm trying to serialize a KeyValuePair property in C# that looks like this:
[JsonDisplayName("custom")]
public KeyValuePair<string,string> Custom { get; set; }
to JSON by setting the property with:
MyClass.Custom = new KeyValuePair<string, string>("destination", destination);
But the output I get looks something like this:
"custom":{"Key":"destination","Value":"Paris"}
Instead I want:
"custom":{"destination":"Paris"}
Any ideas how? I'm using Compact Framework and Visual Studio 2008 so I prefer not to use any external library. You're help is greatly appreciated.
Update: I have to use my company's Model class which has a SetCustom method that throws an exception if I use a dictionary.
You can use dictionary instead of key value pair
public class A
{
[JsonProperty("custom")]
public Dictionary<string, string> Custom
{
get;
set;
}
}
public class Program
{
public static void Main()
{
A custom = new A();
custom.Custom = new Dictionary<string, string>(){
{"destination1", "foo"},
{"destination2", "bar"},
};
Console.WriteLine(JsonConvert.SerializeObject(custom));
}
}
This will produce
{"custom":{"destination1":"foo","destination2":"bar"}}
Or if you want to stick with KeyValuePair
you will need to create your own converter
public class A
{
[JsonProperty("custom")]
public KeyValuePair<string, string> Custom
{
get;
set;
}
}
class KeyValueStringPairConverter : JsonConverter
{
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
KeyValuePair<string, string> item = (KeyValuePair<string, string>)value;
writer.WriteStartObject();
writer.WritePropertyName(item.Key);
writer.WriteValue(item.Value);
writer.WriteEndObject();
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
throw new NotImplementedException();
}
public override bool CanConvert(Type objectType)
{
return objectType == typeof (KeyValuePair<string, string>);
}
}
public class Program
{
public static void Main()
{
A custom = new A();
JsonSerializerSettings settings = new JsonSerializerSettings{Converters = new[]{new KeyValueStringPairConverter()}};
custom.Custom = new KeyValuePair<string, string>("destination", "foo");
Console.WriteLine(JsonConvert.SerializeObject(custom, settings));
}
}
Don't forget download from NuGet Newtonsoft.Json
class Program
{
static void Main(string[] args)
{
String [,] arr = new String[1,2];
arr[0,0] = "Hello";
arr[0,1] = "World";
Console.WriteLine(JsonConvert.SerializeObject(arr));
Console.ReadKey(true);
//[["Hello","World"]]
}
}
I had the same question as the OP and Bob's answer did the trick for me. Just wanted to share that the final code differs a bit if you're using System.Text.Json.Serialization in .NET Core / .NET 5+ instead of Newtonsoft.Json.
public class StringKeyValuePairConverter : JsonConverter<KeyValuePair<string, string>>
{
public override KeyValuePair<string, string> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
{
throw new NotImplementedException();
}
public override void Write(Utf8JsonWriter writer, KeyValuePair<string, string> value, JsonSerializerOptions options)
{
writer.WriteStartObject();
writer.WritePropertyName(value.Key);
writer.WriteStringValue(value.Value);
writer.WriteEndObject();
}
}
It's mostly the same, except value
is strongly typed, eliminating the need for a cast, and WriteStringValue
(or the appropriate type-specific variant) is used instead of WriteValue
.
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