How to Convert Json String into DataTable in ASP.Net with C#

问题

I am using this API. It gives json output according to user input. For Example:

{
"apple.com":{"status":"regthroughothers","classkey":"domcno"},
"asdfgqwx.com":{"status":"available","classkey":"domcno"},
"microsoft.org":{"status":"unknown"},
"apple.org":{"status":"unknown"},
"microsoft.com":{"status":"regthroughothers","classkey":"domcno"},
"asdfgqwx.org":{"status":"unknown"}
}

Now I want to change this json output in dataTable and then Bind in Data Control like Gridview and repeater.

I am using this method to do this but when I passed above json output in this method , It throws an Error

Unexpected JSON token when reading DataTable. Expected StartArray, got StartObject. Path '', line 1, position 1.

回答1:

To convert to DataTable You must understood what You are doing:

DataTable represents a collection of rows and columns your JSON string must represent a collection which can by convert to collection of rows and columns.

This is example of correct JSON file which can by change to DataTable:

[{
    "column1": "1788",
    "column2": "19"
},
{
    "column1": "1789",
    "column2": "24"
},
{
    "column1": "1790",
    "column2": "24"
},
{
    "column1": "1790",
    "column2": "23"
},
{
    "column1": "1790",
    "column2": "21"
}]

Each pair column1 and column2 is the row

Now Your JSON is not good. I change it to this: (correct DataTable schema)

  [{
        "name": "apple.com",
        "status": "regthroughothers",
        "classkey": "domcno"
    },
    {
        "name": "asdfgqwx.com",
        "status": "available",
        "classkey": "domcno"
    },
    {
        "name": "microsoft.org",
        "status": "unknown",
        "classkey": ""
    },
    {
        "name": "apple.org",
        "status": "unknown",
        "classkey": ""
    },
    {
        "name": "microsoft.com",
        "status": "regthroughothers",
        "classkey": "domcno"
    },
    {
        "name": "asdfgqwx.org",
        "status": "unknown",
        "classkey": "domcno"
    }]

And I add [ sign and ] sign at the beginning and the end of array

Next You can do this. It is working example for deserializing above JSON string to DataTable

using Newtonsoft.Json;

public class JsonExample
    {

        private string jsonObject = "[{ \"name\": \"apple.com\",    \"status\": \"regthroughothers\",   \"classkey\": \"domcno\"},{ \"name\": \"asdfgqwx.com\", \"status\": \"available\",  \"classkey\": \"domcno\"},{ \"name\": \"microsoft.org\",    \"status\": \"unknown\",    \"classkey\": \"\"},{   \"name\": \"apple.org\",    \"status\": \"unknown\",    \"classkey\": \"\"},{   \"name\": \"microsoft.com\",    \"status\": \"regthroughothers\",   \"classkey\": \"domcno\"},{ \"name\": \"asdfgqwx.org\", \"status\": \"unknown\",    \"classkey\": \"domcno\"}]".Trim();

        public JsonExample()
        { 
            DataTable items = JsonConvert.DeserializeObject<DataTable>(jsonObject);

            foreach (DataRow item in items.Rows)
            {
                Console.WriteLine($"Name: {item[0]} Status: {item[1]}  classkey {item[2]} " );
            }

        }
    }

BUT if You sill don;t want to change JSON file

private string jsonObject = JSON_String.Replace("{", "[{").Replace("}", "}]");

public JsonExample()
        {
            JArray jArray = JArray.Parse(jsonObject);

            DataTable dt = new DataTable();

            dt.Columns.Add("Name");
            dt.Columns.Add("status");
            dt.Columns.Add("classkey");

            foreach (JProperty item in jArray[0])
            {
                var jArray2 = JArray.Parse(item.Value.ToString());

                foreach (var item2 in jArray2)
                {
                    dt.Rows.Add(item.Name, item2["status"], item2["classkey"]);
                    Console.WriteLine($"Name: {item.Name} Status: {item2["status"]}  classkey {item2["classkey"]} ");
                }
            } 
        }

Effect is the same as but You don't need do change the JSON String exept 2 replace.

Effect when You parse first string with method I write:

Additional information:

Convert JSON response to DataTable

来源：https://stackoverflow.com/questions/35482580/how-to-convert-json-string-into-datatable-in-asp-net-with-c-sharp

标签

ASP.NET

datatable

json-api