WZExport/Pages/DBConfigs/Create.cshtml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Newtonsoft.Json;
using WZExport.Models;

namespace WZExport.Pages.DBConfigs
{
    public class CreateModel : PageModel
    {
        [BindProperty]
        public DBConfig DBConfig { get; set; }

        public IActionResult OnPostAsync()
        {
            string configStr = System.IO.File.ReadAllText("dBConfig.json");
            var dBConfigs = JsonConvert.DeserializeObject<List<DBConfig>>(configStr);
            dBConfigs.Add(DBConfig);
            System.IO.File.WriteAllText("dBConfig.json", JsonConvert.SerializeObject(dBConfigs));
            return RedirectToPage("./Index");
        }
    }
}