Localdb Mssqllocaldb ((full)) May 2026

public class User { public int Id { get; set; } public string Username { get; set; } public string Email { get; set; } public DateTime CreatedAt { get; set; } } // Check if LocalDB is running and accessible public static bool TestLocalDBConnection() { try { using var connection = new SqlConnection(@"Server=(localdb)\MSSQLLocalDB;Trusted_Connection=true;"); connection.Open(); Console.WriteLine("✓ LocalDB is accessible"); using var command = new SqlCommand("SELECT @@VERSION", connection); string version = command.ExecuteScalar().ToString(); Console.WriteLine($"✓ SQL Server Version: {version.Substring(0, Math.Min(50, version.Length))}..."); return true; } catch (Exception ex) { Console.WriteLine($"✗ Error connecting to LocalDB: {ex.Message}"); Console.WriteLine("\nTroubleshooting steps:"); Console.WriteLine("1. Run 'sqllocaldb start MSSQLLocalDB' in command prompt"); Console.WriteLine("2. Ensure SQL Server LocalDB is installed"); Console.WriteLine("3. Check if Windows Firewall is blocking the connection"); return false; } } Quick Start Summary # 1. Create and start LocalDB sqllocaldb create "MyApp" sqllocaldb start "MyApp" 2. Get connection string sqllocaldb info "MyApp" 3. Use in C# code "Server=(localdb)\MyApp;Database=MyDatabase;Trusted_Connection=true;" 4. Stop when done sqllocaldb stop "MyApp"

public async Task<int> InsertUserAsync(User user) { using var connection = new SqlConnection(_connectionString); var sql = "INSERT INTO Users (Username, Email) VALUES (@Username, @Email); SELECT CAST(SCOPE_IDENTITY() as int)"; return await connection.QuerySingleAsync<int>(sql, user); } localdb mssqllocaldb

var builder = WebApplication.CreateBuilder(args); public class User { public int Id {