winforms-sql-connection [SINGCOL]

TestWins/Form1.cs

@@ -1,13 +1,13 @@
-using System.Drawing.Text;
 using TestWins.Controller;
+using TestWins.Model;
 
 namespace TestWins;
 
 public partial class Form1 : Form
 {
-    //business
-
     private readonly StudentController controller = new StudentController();
+    private DataGridViewRow? selectedRow;
+
     public Form1()
     {
         InitializeComponent();
@@ -21,23 +21,109 @@ private void loadData()
 
     private void btnAdd_Click(object sender, EventArgs e)
     {
+        if (!ValidateFields())
+        {
+            MessageBox.Show("Please fill in all required fields!");
+            return;
+        }
 
+        var success = controller.add(GetStudent());
+        ShowResult(success, "Added");
+        ClearAndRefresh();
     }
 
     private void btnUpdate_Click(object sender, EventArgs e)
     {
+        if (selectedRow == null)
+        {
+            MessageBox.Show("Select a row first!");
+            return;
+        }
+
+        if (!ValidateFields())
+        {
+            MessageBox.Show("Please fill in all required fields!");
+            return;
+        }
 
+        var success = controller.update(GetStudent());
+        ShowResult(success, "Updated");
+        ClearAndRefresh();
     }
 
     private void btnDelete_Click(object sender, EventArgs e)
     {
+        if (selectedRow == null)
+        {
+            MessageBox.Show("Select a row first!");
+            return;
+        }
+
+        if (MessageBox.Show("Delete this record?", "Confirm", MessageBoxButtons.YesNo) == DialogResult.No)
+            return;
+
+        int id = Convert.ToInt32(selectedRow.Cells["Id"].Value);
+        var success = controller.delete(id);
+
+        ShowResult(success, "Deleted");
+        ClearAndRefresh();
+    }
+
+    private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
+    {
+        if (e.RowIndex < 0) return;
+
+        selectedRow = dataGridView1.Rows[e.RowIndex];
+        PopulateFields();
+    }
+
+    //HELPERS 
+
+    private bool ValidateFields()
+    {
+        return !string.IsNullOrWhiteSpace(txtName.Text) &&
+               !string.IsNullOrWhiteSpace(txtCourse.Text);
+    }
+
+    private Student GetStudent()
+    {
+        return new Student
+        {
+            Id = int.TryParse(txtId.Text, out int id) ? id : 0,
+            Name = txtName.Text,
+            Course = txtCourse.Text,
+            Age = int.TryParse(txtAge.Text, out int age) ? age : 0
+        };
+    }
 
+    private void PopulateFields()
+    {
+        if (selectedRow == null) return;
 
+        txtId.Text = selectedRow.Cells["Id"].Value?.ToString() ?? "";
+        txtName.Text = selectedRow.Cells["Name"].Value?.ToString() ?? "";
+        txtCourse.Text = selectedRow.Cells["Course"].Value?.ToString() ?? "";
+        txtAge.Text = selectedRow.Cells["Age"].Value?.ToString() ?? "";
+    }
 
+    private void ClearAndRefresh()
+    {
+        ClearFields();
+        loadData();
     }
 
-    private void dataGridView1_CellClick(object sender, EventArgs e)
+    private void ClearFields()
     {
+        txtId.Clear();
+        txtName.Clear();
+        txtCourse.Clear();
+        txtAge.Clear();
+        selectedRow = null;
+    }
 
+    private void ShowResult(bool success, string action)
+    {
+        string msg = success ? $"✅ {action} successfully!" : $"❌ Failed to {action}!";
+        MessageBox.Show(msg, success ? "Success" : "Error");
     }
 }

TestWins/model/ConnectionSql.cs

@@ -1,22 +1,61 @@
 namespace TestWins.Model;
 
-//dotnet add package MySql.Data
+// dotnet add package MySql.Data
 using MySql.Data.MySqlClient;
+using System;
+using System.Data;
 
 public class ConnectionSql
 {
-    private readonly string _connectionString = "server=localhost;database=student;uid=root;pwd=root";
-        private MySqlConnection _conn;
+    private readonly string _connectionString = 
+        "server=localhost;database=student;uid=root;pwd=root";
+
+    private MySqlConnection _conn;
 
     public MySqlConnection connectSql()
     {
+        try
+        {
+            Console.WriteLine("Connecting to DB...");
+
+            _conn = new MySqlConnection(_connectionString);
 
-        Console.WriteLine("Connecting to DB");
+            _conn.Open();
 
-        _conn = new MySqlConnection(_connectionString);
+            Console.WriteLine("Database connection successful");
 
-        Console.WriteLine(_conn == null ? "Datbase Connection Failed" : "Database connection successful");
+            return _conn;
+        }
+        catch (MySqlException ex)
+        {
+            Console.WriteLine("Database Error: " + ex.Message);
+            return null;
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine("Unexpected Error: " + ex.Message);
+            return null;
+        }
+    }
 
-        return _conn;
+    public void closeSql()
+    {
+        try
+        {
+            if (_conn != null && _conn.State == ConnectionState.Open)
+            {
+                _conn.Close();
+                Console.WriteLine("Connection closed");
+            }
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine("Error closing connection: " + ex.Message);
+        }
+    }
+
+    public MySqlConnection getConnection()
+    {
+        return connectSql();
     }
-}
+}