Здравствуйте, Эйнсток Файр, Вы писали:

How to build a unicode string with emojis in c#?

I've been using the following code to translate unicode parts that are taken from a text file in a format of string array ["1F3F3", "FE0F", "200D", "1F308"]. The mentioned unicode parts are a sample of 🏳️‍🌈 emoji and are taken from unicode.org resource(#1553 on the page).

public static void PrintEmoji(params string[] unicodeParts)
{
    var unicodeBuilder = new StringBuilder();
    foreach (var unicodePart in unicodeParts)
    {
        unicodeBuilder.Append(char.ConvertFromUtf32(Convert.ToInt32(unicodePart,16)));
    }
    if(unicodeBuilder.ToString() is var unicodeResult && !string.IsNullOrWhiteSpace(unicodeResult))
        Console.WriteLine(unicodeResult);
}

То есть использовать Encoding.UTF32. Не?