Display formatted JSON in the view in ASP.NET MVC

You could use JSON.NET which supports to control the JSON format and indent it:

<pre>    @Html.Raw(JsonConvert.SerializeObject(Student.CreateEmpty(), Formatting.Indented))</pre>

An other way using Newtonsoft. Note the pre html tag is important to maintain the format.

<pre>@Html.Raw(Newtonsoft.Json.Linq.JValue.Parse(Student.CreateEmpty()).ToString(Newtonsoft.Json.Formatting.Indented)</pre>

My solution is just formatting HTML directly (for debug purposes)You could make this much fancier.

    public static void FormatJSONObject(object o, StringBuilder sb, int indent)    {        if(o.GetType() == typeof(System.Object[]))        {            sb.AppendLine("[<br>");            int idx = 0;            foreach(object obj in (object[])o)            {                sb.Append("<b><i>" + idx + "</i></b><br><div style='padding-left: " + indent + "em;'>");                FormatJSONObject(obj, sb, indent + 2);                sb.AppendLine("</div>");                idx++;            }            sb.AppendLine("]<br>");        }        else if(o.GetType() == typeof(Dictionary<string, object>))        {            sb.AppendLine("{<br><div style='padding-left: " + indent + "em;'>");            foreach (var v in (Dictionary<string, object>)o)            {                sb.Append("<b>");                sb.Append(v.Key);                sb.Append("</b> : ");                FormatJSONObject(v.Value, sb, indent + 2);            }            sb.AppendLine("</div>}<br>");        }        else        {            sb.Append(o.ToString());            sb.AppendLine("<br>");        }    }

Then called in my ASP server side button click handler...

    protected  void GoButton_Click(object sender, EventArgs e)    {        RegisterAsyncTask(new PageAsyncTask(LoadTestData));    }    public async Task LoadTestData()    {        using (HttpClient client = new HttpClient())        {            // Like "http://jsonplaceholder.typicode.com"            client.BaseAddress = new Uri(APIURLBase.Text);            client.DefaultRequestHeaders.Accept.Clear();            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("text/html"));            // Like "posts/1"            HttpResponseMessage response = await client.GetAsync(APIURLRequest.Text);            if (response.IsSuccessStatusCode)            {                StringBuilder sb = new StringBuilder();                sb.AppendLine("<H1>Return Status:</H1> " + response.StatusCode.ToString() + "<br>");                sb.AppendLine("<H1>Headers</H1><br>");                foreach (var h in response.Headers)                {                    foreach (var v in h.Value)                    {                        sb.AppendLine("<label>" + h.Key + "</label> " + v + "<br>");                    }                }                sb.AppendLine("<H1>Content</H1><br>");                sb.AppendLine("<label>Content Type: </label>" + Response.ContentType + "<br>");                Stream memStream = new MemoryStream();                Stream bodyStream = await response.Content.ReadAsStreamAsync();                bodyStream.CopyTo(memStream);                memStream.Position = 0;                using (StreamReader reader = new StreamReader(memStream))                {                    string body = reader.ReadToEnd();                    if (ShowRawContentCB.Checked)                    {                        sb.AppendLine(body + "<br>");                    }                    else                    {                        JavaScriptSerializer ser = new JavaScriptSerializer();                        object o = ser.Deserialize(body, typeof(object));                        FormatJSONObject(o, sb);                    }                }                this.results.InnerHtml = sb.ToString();            }            else            {                this.results.InnerHtml = "<label>Error:</label> " + response.StatusCode.ToString();            }        }    }