Test the connection string in your ASP.NET Core MVC

 To test the connection string in your ASP.NET Core MVC application, follow these steps:

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1. Inject and Read Connection String in a Controller

You can inject IConfiguration into a controller and check if the connection string is being read correctly.

Modify HomeController.cs (or create a new controller)

csharp
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using System.Data.SqlClient;

namespace YourNamespace.Controllers
{
    public class HomeController : Controller
    {
        private readonly IConfiguration _configuration;

        public HomeController(IConfiguration configuration)
        {
            _configuration = configuration;
        }

        public IActionResult TestConnection()
        {
            string connectionString = _configuration.GetConnectionString("ConnStrMVC");

            try
            {
                using (SqlConnection conn = new SqlConnection(connectionString))
                {
                    conn.Open();
                    return Content("Database Connection Successful!");
                }
            }
            catch (Exception ex)
            {
                return Content("Database Connection Failed: " + ex.Message);
            }
        }
    }
}

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2. Configure Dependency Injection in Program.cs

Ensure that appsettings.json is properly loaded by adding builder.Configuration in Program.cs:

csharp
var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddControllersWithViews();

// Make sure appsettings.json is properly loaded
builder.Services.Configure<YourAppSettings>(builder.Configuration.GetSection("ConnectionStrings"));

var app = builder.Build();

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3. Run and Test

• Start your application.
• Navigate to:

  arduino
  https://localhost:port/Home/TestConnection
  

• If the connection is successful, it will show "Database Connection Successful!"
• If there is an issue, the error message will be displayed.

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4. (Optional) Test in Program.cs Before Running the App

If you want to test before the application starts, add the following in Program.cs:

csharp
string connectionString = builder.Configuration.GetConnectionString("ConnStrMVC");

try
{
    using (SqlConnection conn = new SqlConnection(connectionString))
    {
        conn.Open();
        Console.WriteLine("Database Connection Successful!");
    }
}
catch (Exception ex)
{
    Console.WriteLine("Database Connection Failed: " + ex.Message);
}

Then, run the project and check the Output Console for results.

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5. Verify SQL Server

If the connection fails, check:

• SQL Server is running (services.msc → SQL Server is started)
• Correct server name (. or (local) for local SQL, or specify MACHINE_NAME\SQLEXPRESS if using SQL Express)
• TrustServerCertificate=True if using Windows Authentication
• Use User ID=sa;Password=yourpassword; if using SQL Authentication

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This method ensures that your connection string works before implementing database operations.