从文件读取Json数据

Question

Hello i'm trying to read json data from a text file but it doesn't work. when i try to get data from a website then it works fine. Anyone know a solution to fix this problem ? thanks in advance.

            private void Form1_Load(object sender, EventArgs e)
        {
            string path = @"C:\Users\spacefrog\Documents\Visual Studio 2017\Projects\json_test_solution\json_test\bin\Debug\test.json";

          //  Stream stream = File.OpenRead(path);
            WebClient client = new WebClient();
            Stream stream = client.OpenRead("https://www.cryptocompare.com/api/data/coinlist/"); // works perfect
            /*
            Stream stream = client.OpenRead(path); // doesn't work
            Stream stream = File.OpenRead(path); // doesn't work
            */

/* File Data content (same as website)
{
"Response": "Success",
"Message": "Coin list succesfully returned!",
"BaseImageUrl": "https://www.cryptocompare.com",
"BaseLinkUrl": "https://www.cryptocompare.com",
"Data": {
"LTC": {
"Id": "3808",
"Url": "/coins/ltc/overview",
"ImageUrl": "/media/19782/ltc.png",
"Name": "LTC",
"CoinName": "Litecoin",
"FullName": "Litecoin (LTC)",
"Algorithm": "Scrypt",
"ProofType": "PoW",
"SortOrder": "2"
}
...
},
"Type": 100
}
    */

StreamReader reader = new StreamReader(stream);
JObject json = JObject.Parse(reader.ReadLine());
stream.Close();



MessageBox.Show((string)json["Response"]);

}

Answer 1

JObject json = JObject.Parse(reader.ReadLine());

How should the JSON.NET Parser parse the first line? Looking at your comment, the first line seems to be

{

Does not look like a valid JSON object. Take a look at the ReadToEnd method. By the way, you may want to use the StreamReader within a using scope.

Answer 2

You don't have to use a temp file to parse that json

WebClient webClient = new WebClient();
var json = webClient.DownloadString("https://www.cryptocompare.com/api/data/coinlist/");

var rootObj = JsonConvert.DeserializeObject<SOTest.RootObject>(json);
//OR var jObj = JObject.Parse(json);

---

if you really want to save to a file you can use

webClient.DownloadFile(url,filename);

or write the json above to a file

File.WriteAllText(filename, json);

or if you want to go the client.OpenRead way

var f = File.Create(filename);
stream.CopyTo(f);

---

public class SOTest
{
    public class DataItem
    {
        public string Id { get; set; }
        public string Url { get; set; }
        public string ImageUrl { get; set; }
        public string Name { get; set; }
        public string Symbol { get; set; }
        public string CoinName { get; set; }
        public string FullName { get; set; }
        public string Algorithm { get; set; }
        public string ProofType { get; set; }
        public string FullyPremined { get; set; }
        public string TotalCoinSupply { get; set; }
        public string PreMinedValue { get; set; }
        public string TotalCoinsFreeFloat { get; set; }
        public string SortOrder { get; set; }
    }

    public class RootObject
    {
        public string Response { get; set; }
        public string Message { get; set; }
        public string BaseImageUrl { get; set; }
        public string BaseLinkUrl { get; set; }
        public Dictionary<string,DataItem> Data { get; set; }
        public int Type { get; set; }
    }
}