.Net Core: Read Connection String from AppSettings.json file

谁借莪１个温暖的怀抱￠ 2023-10-01 19:36 44阅读 0赞

In this article I will explain with an example, how to read Connection String from AppSettings.json file in .Net Core and ASP.Net MVC Core.

Microsoft has replaced System.Configuration class with IConfiguration interface in .Net Core 2.0.

**What is IConfiguration**

The IConfiguration is an interface for .Net Core 2.0.

The IConfiguration interface need to be injected as dependency in the Controller and then later used throughout the Controller.

The IConfiguration interface is used to read Settings and Connection Strings from AppSettings.json file.

**Namespaces**

You will need to import the following namespace.

using Microsoft.Extensions.Configuration;

**Adding the AppSettings.json file**

In order to add AppSettings.json file, right click on the Project in Solution Explorer. Then click Add, then New Item and then choose App Settings File option (shown below) and click Add button.

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Once the File is created, it will have a DefaultConnection, below that a new Connection String entry is added.

"ConnectionStrings": \{

"DefaultConnection": "Server=(localdb)\\\\MSSQLLocalDB;Database=\_CHANGE\_ME;Trusted\_Connection=True;MultipleActiveResultSets=true",

"MyConn": "Data Source=.\\\\SQL2017;Initial Catalog=AjaxSamples;Integrated Security=true"

**Reading Connection String from AppSettings.json file using IConfiguration interface**

In the below example, the IConfiguration is injected in the Controller and assigned to the private property Configuration.

Then inside the Controller, the Connection String is read from the AppSettings.json file using the GetConnectionString function.

public class HomeController : Controller

privateIConfiguration Configuration;

public HomeController(IConfiguration \_configuration)

Configuration = \_configuration;

publicIActionResult Index()

string connString = this.Configuration.GetConnectionString("MyConn");

return View();

**Screenshot**

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**Downloads**

Download

using System;
    using System.Collections.Generic;
    using System.Diagnostics;
    using System.Linq;
    using System.Threading.Tasks;
    using Microsoft.AspNetCore.Mvc;
    using crudf.Models;
    using MySql.Data.MySqlClient;
    
    using Microsoft.Extensions.Configuration;
    
    
    //function page[d]
    namespace crudf.Controllers
    {
        public class HomeController : Controller
        {
            private IConfiguration Configuration;
            private string connString;
    
            public HomeController(IConfiguration _configuration)
            {
                Configuration = _configuration;
                connString = this.Configuration.GetConnectionString("DefaultConnection");
            }
            public IActionResult Index()
    
            //function for index page and fetch from db[d]
            {
                List<Customer> Customers = new List<Customer>();
                //string connString = this.Configuration.GetConnectionString("DefaultConnection");
    
                using (MySqlConnection con = new MySqlConnection(connString))
    
                {
                    con.Open();
                    MySqlCommand cmd = new MySqlCommand("select * from customer", con);
                    MySqlDataReader reader = cmd.ExecuteReader();
    
                    while (reader.Read())
                    {
                        Customer Customer = new Customer();
                        Customer.CustomerId = Convert.ToInt32(reader["CustomerId"]);
                        Customer.FullName = reader["FullName"].ToString();
                        Customer.CusCode = reader["CusCode"].ToString();
                        Customer.Location = reader["Location"].ToString();
    
                        Customers.Add(Customer);
    
    
                    }
                    reader.Close();
    
                }
                //view karan customer return karanva
                return View(Customers);
            }
    
    
            //delete function
    
            public ActionResult Delete(int id)
    
            {
                //string connString = this.Configuration.GetConnectionString("DefaultConnection");
                using (MySqlConnection con = new MySqlConnection(connString))
    
                {
                    con.Open();
                    MySqlCommand cmd = new MySqlCommand("DELETE FROM customer Where CustomerId =" + id, con);
                    MySqlDataReader reader = cmd.ExecuteReader();
    
                    reader.Close();
    
    
                }
    
                return RedirectToAction("Index");
            }
    
            //create function
            public IActionResult Create()
            {
                return View();
    
            }
    
            [HttpPost]
            public IActionResult Create(int CustomerId, string FullName, string CusCode, string Location)
            {
                //connection eka hadanva
                //string connString = this.Configuration.GetConnectionString("DefaultConnection");
                using (MySqlConnection con = new MySqlConnection(connString))
    
                {
                    con.Open();
                    var command = "insert into customer(FullName,CusCode,Location) values ('" + FullName + "' ,'" + CusCode + "','" + Location + "')";
                    MySqlCommand cmd = new MySqlCommand(command, con);
                    MySqlDataReader reader = cmd.ExecuteReader();
                    //reader kiyan ekn aragen eka ececute kranva query eken ena data tika ececute karal eliyata denva 
                    reader.Close();
    
    
                }
    
    
                return View();
            }
    
            //edit 
    
            public IActionResult Edit(int id)
            {
                Customer Customer = new Customer();
                //string connString = this.Configuration.GetConnectionString("DefaultConnection");
                using (MySqlConnection con = new MySqlConnection(connString))
    
    
                {
                    con.Open();
                    MySqlCommand cmd = new MySqlCommand("select * from customer where CustomerId =" + id, con);
                    MySqlDataReader reader = cmd.ExecuteReader();
    
                    while (reader.Read())
                    {
                        //extract data...fetch
                        Customer.CustomerId = Convert.ToInt32(reader["CustomerId"]);
                        Customer.FullName = reader["FullName"].ToString();
                        Customer.CusCode = reader["CusCode"].ToString();
                        Customer.Location = reader["Location"].ToString();
    
    
    
                    }
                    reader.Close();
                }
                return View(Customer);
    
            }
    
            [HttpPost]
            public IActionResult Edit(int CustomerId, string FullName, string CusCode, string Location)
    
            {
                //string connString = this.Configuration.GetConnectionString("DefaultConnection");
                using (MySqlConnection con = new MySqlConnection(connString))
    
                {
                    con.Open();
                    MySqlCommand cmd = new MySqlCommand("UPDATE customer SET FullName = '" + FullName + "', CusCode = '" + CusCode + "' , Location = '" + Location + "' WHERE CustomerId =" + CustomerId, con);
                    MySqlDataReader reader = cmd.ExecuteReader();
    
                    reader.Close();
    
    
                }
    
                return RedirectToAction("Index");
            }
    
    
            public IActionResult About()
            {
                ViewData["Message"] = "Your application description page.";
    
                return View();
            }
    
            public IActionResult Contact()
            {
                ViewData["Message"] = "Your contact page.";
    
                return View();
            }
    
            public IActionResult Privacy()
            {
                return View();
            }
    
            [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
            public IActionResult Error()
            {
                return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
            }
        }
    }

[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/7a64a9fd28dd43cb88d936831d7d5c2a.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16 1]: https://img-blog.csdnimg.cn/339cba69ba134aa1a0ea8eb6e4bcc633.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16