winforms-sql-connection [BABAYSON]

ConnectionSql.cs

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+namespace TestWins.Model;
+
+//dotnet add package MySql.Data
+using MySql.Data.MySqlClient;
+
+public class ConnectionSql
+{
+    private readonly string _connectionString = "server=localhost;database=student;uid=root;pwd=root";
+        private MySqlConnection _conn;
+
+    public MySqlConnection connectSql()
+    {
+        return new MySqlConnection(_connectionString);
+
+    }
+    public MySqlConnection GetOpenConnection()
+    {
+        try
+        {
+            var conn = new MySqlConnection(_connectionString);
+            conn.Open();
+            Console.WriteLine("Database connection successful");
+            return conn;
+        }
+        catch (MySqlException ex)
+        {
+            Console.WriteLine($"Database connection failed: {ex.Message}");
+            return null;
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"An unexpected error occurred: {ex.Message}");
+            return null;
+        }
+    }
+        Console.WriteLine("Connecting to DB");
+
+        _conn = new MySqlConnection(_connectionString);
+
+        Console.WriteLine(_conn == null ? "Datbase Connection Failed" : "Database connection successful");
+
+        return _conn;
+    }
+}

FixedConnectionSql.cs

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+using MySql.Data.MySqlClient;
+using TestWins.Model;
+
+namespace TestWins.Repository
+{
+  public class StudentRepository
+  {
+    private readonly FixedConnectionSql_db = new FixedConnectionSql();
+
+    public void Create(Student student)
+    {
+      using var conn = _db.connectSql();
+      conn.Open();
+
+      string query = "INSERT INTO students (name, age, course) VALUES (@name, @age, @course)";
+      using var cmd = new MySqlCommand(query, conn);
+
+      cmd.Parameters.AddWithValue("@name", student.Name);
+      cmd.Parameters.AddWithValue("@age", student.age);
+      cmd.Parameters.AddWithValue("@course", student.course);
+
+      cmd.ExecuteNonQuery();
+    }
+
+    public List<Studnent> GetAll()
+    {
+      var list = new List<Student>();
+
+      using var conn  = _db.connectionSql();
+      conn.Open();
+
+      string query = "SELECT * FROM students";
+      using var cmd = new MySqlCommand(query, conn);
+      using var reader = cmd.ExecuteReader();
+
+      while(reader.Read())
+      {
+        list.Add(new Student
+        {
+          studentId = reader.GetInt32(0),
+          Name = reader.GetString(1),
+          age = reader.GetInt(32),
+          course = reader.GetString(3),
+        });
+      }
+      return list;
+    }
+
+    public void Update(Student student)
+    {
+      using var conn = _db.connectSql();
+      conn.Open();
+
+      string query = "UPDATE students SET name = @name, age = @age, course = @course WHERE id = @id";
+      using var cmd = new MySqlCommand(query, conn);
+
+      cmd.Parameters.AddWithValue("@id", student.studentId);
+      cmd.Parameters.AddWithValue("@name", student.Name);
+      cmd.Parameters.AddwithValue("@age", student.age);
+      cmd.Parameters.AddWithValue("@course", student.course);
+
+      cmd.ExecuteNonQuery();
+    }
+
+    public void Delete(int id)
+    {
+      using var conn = _db.connectSql();
+      conn.Open();
+
+      string query = "DELETE FROM students WHERE id = @id";
+      using var cmd = new MySqlCommand(query, conn);
+
+      cmd.Parameters.AddWithValue("@id", id);
+
+      cmd.ExecuteNonQuery();
+    }
+  }
+}

Form1.cs

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+using System.Drawing.Text;
+using TestWins.Controller;
+
+namespace TestWins;
+
+public partial class Form1 : Form
+{
+
+    private readonly StudentController controller = new StudentController();
+    public Form1()
+    {
+        InitializeComponent();
+        loadData();
+    }
+
+    private void loadData()
+    {
+        dataGridView1.DataSource = controller.getAll();
+    }
+
+    private void btnAdd_Click(object sender, EventArgs e)
+    {
+        Students s = new Students()
+        {
+            Name = txtName.Text,
+            Age = int.Parse(txtAge.Text),
+            Course = txtCourse.Text
+        };
+        controller.insert(s);
+        loadData();
+    }
+
+    private void btnUpdate_Click(object sender, EventArgs e)
+    {
+        Students S = new Students()
+        {
+            Id = int.Parse(txtId.Text),
+            Name = txtName.Text,
+            Age = int.Parse(txtAge.Text),
+            Course = txtCourse.Text
+        };
+        controller.update(S);
+        loadData(); 
+    }
+
+    private void btnDelete_Click(object sender, EventArgs e)
+    {
+       int id = int.Parse(txtId.Text);
+        controller.delete(id);
+        loadData();
+    }
+
+    private void dataGridView1_CellClick(object sender, EventArgs e)
+    {
+        if (e.RowIndex >= 0)
+        {
+            DataGridViewRow row = dataGridView1.Rows[e.RowIndex];
+            txtId.Text = row.Cells["Id"].Value.ToString();
+            txtName.Text = row.Cells["Name"].Value.ToString();
+            txtAge.Text = row.Cells["Age"].Value.ToString();
+            txtCourse.Text = row.Cells["Course"].Value.ToString();s
+        }
+    }
+}