OnDoc/OnDoc_JSONViewer/Form1.cs

using Syncfusion.XPS;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Newtonsoft;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using Syncfusion.Windows.Forms.PdfViewer;

namespace OnDoc_JSONViewer
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            listBox1.Items.Clear();
            DirectoryInfo dir = new DirectoryInfo(textBox1.Text);
            foreach (FileInfo file in dir.GetFiles())
            {
                listBox1.Items.Add(file.Name);
            }

        }

        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            string ext = System.IO.Path.GetExtension(listBox1.SelectedItem.ToString().ToUpper());
            string filename = textBox1.Text + @"\" + listBox1.SelectedItem.ToString();
            textBox2.Text = "";
            switch (ext)
            {
                case ".PDF":
                    pdfViewerControl1.Load(filename);
                    break;
                case ".JSON":
                    string jsonstring;
                    using (StreamReader streamReader = new StreamReader(filename, Encoding.UTF8))
                    {
                        jsonstring = streamReader.ReadToEnd();
                    }
                    // var prettyJson1 = JsonConvert.SerializeObject(jsonstring, Formatting.Indented);

                    //dynamic parsedJson1 = JsonConvert.DeserializeObject(jsonstring);
                    //prettyJson1 = JsonConvert.SerializeObject(parsedJson1, Formatting.Indented);
                    string source2 = jsonstring;
                    dynamic data2 = JObject.Parse(source2);
                    string data3 = JObject.Parse(jsonstring)["bpNummer"].ToString();
                    string data4 = JObject.Parse(jsonstring)["personNummer"].ToString();
                    textBox2.Text= data3 + Environment.NewLine+data4;
                    if (toolStripCheckBox1.Checked == true)
                    {
                        try
                        {
                            string source = jsonstring;
                            dynamic data = JObject.Parse(source);
                            string data1 = JObject.Parse(jsonstring)["dokumentDatei"].ToString();


                            var stream = new MemoryStream(Convert.FromBase64String(data1));


                            if (stream.Length > 0)
                            {
                                this.pdfViewerControl1.Load(stream);
                                this.pdfViewerControl1.Visible = true;
                                pdfViewerControl1.ZoomMode = ZoomMode.FitWidth;
                                stream = null;
                            }
                            else
                            {

                            }

                        }
                        catch { }
                    }
                    break;

            }
        }
    }
}