using System;
            using System.Collections.Generic;
            using System.ComponentModel;
            using System.Data;
            using System.Drawing;
            using System.Linq;
            using System.Text;
            using System.Threading.Tasks;
            using System.Windows.Forms;
            using System.Data.Sql;
            using System.Data.SqlClient;
            using System.Configuration;

            namespace Students_Desk
            {
            public partial class frmStudents : Form
            {
            string CS = ConfigurationManager.ConnectionStrings["StudentDB"].ConnectionString;
            SqlConnection conn;
            SqlCommand cmd;
            SqlDataAdapter da;
            SqlDataReader rdr;

            public frmStudents()
            {
            InitializeComponent();
            }

            private void frmStudents_Load(object sender, EventArgs e)
            {
            conn = new SqlConnection(CS);
            conn.Open();

            DataTable dt = new DataTable();
            da = new SqlDataAdapter("select * from tblInformation ", conn);
            da.Fill(dt);

            dataGridView1.DataSource = dt;
            }

            private void btnInsert_Click(object sender, EventArgs e)
            {
            if (txtName.Text == string.Empty || txtAge.Text == string.Empty || txtGender.Text == string.Empty || txtCity.Text == string.Empty)
            {
            MessageBox.Show("Data fields cannot be blank!", "info", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
            }
            else
            {
            try
            {
            conn = new SqlConnection(CS);
            conn.Open();

            cmd = new SqlCommand("Insert into tblInformation values(@Name, @Age, @Gender, @City)", conn);
            cmd.CommandType = CommandType.Text;
            cmd.Parameters.AddWithValue("@Name", txtName.Text);
            cmd.Parameters.AddWithValue("@Age", txtAge.Text);
            cmd.Parameters.AddWithValue("@Gender", txtGender.Text);
            cmd.Parameters.AddWithValue("@City", txtCity.Text);
            cmd.ExecuteNonQuery();
            MessageBox.Show("Data saved Successfully!", "info", MessageBoxButtons.OK, MessageBoxIcon.Information);

            DataTable dt = new DataTable();
            da = new SqlDataAdapter("select * from tblInformation ", conn);
            da.Fill(dt);
            dataGridView1.DataSource = dt;
            }
            catch (Exception ex)
            {
            MessageBox.Show(ex.Message);
            }
            }
            }

            private void btnCancel_Click(object sender, EventArgs e)
            {
            ClearFields();
            }

            private void ClearFields()
            {
            txtAge.Clear();
            txtName.Clear();
            txtCity.Clear();
            txtGender.Clear();
            txtSearch.Clear();
            }

            private void btnExit_Click(object sender, EventArgs e)
            {
            DialogResult d = MessageBox.Show("Do you want to close Application?", "Inform", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question);
            if (d == DialogResult.Yes)
            {
            Application.Exit();
            }
            }

            private void btnUpdate_Click(object sender, EventArgs e)
            {
            if (txtSearch.Text == string.Empty)
            {
            MessageBox.Show("Please enter the ID to be updated!", "info", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            else
            {
            try
            {
            conn = new SqlConnection(CS);
            conn.Open();

            cmd = new SqlCommand("Update tblInformation set Name=@Name, Age=@Age, Gender=@Gender, City=@City where ID='" + txtSearch.Text + "'", conn);
            cmd.CommandType = CommandType.Text;
            cmd.Parameters.AddWithValue("@Name", txtName.Text);
            cmd.Parameters.AddWithValue("@Age", txtAge.Text);
            cmd.Parameters.AddWithValue("@Gender", txtGender.Text);
            cmd.Parameters.AddWithValue("@City", txtCity.Text);
            cmd.ExecuteNonQuery();
            MessageBox.Show("Data Updated successfully!", "info", MessageBoxButtons.OK, MessageBoxIcon.Information);
            ClearFields();

            DataTable dt = new DataTable();
            da = new SqlDataAdapter("select * from tblInformation ", conn);
            da.Fill(dt);
            dataGridView1.DataSource = dt;
            }
            catch (Exception ex)
            {
            MessageBox.Show(ex.Message);
            }
            }
            }

            private void btnSearch_Click(object sender, EventArgs e)
            {
            conn = new SqlConnection(CS);
            conn.Open();

            if (txtSearch.Text == string.Empty)
            {
            MessageBox.Show("Please enter the ID to search!", "info", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            else
            {
            cmd = new SqlCommand("select * from tblInformation where ID ='" + txtSearch.Text + "' ", conn);
            rdr = cmd.ExecuteReader();

            if (rdr.HasRows)
            {
            while (rdr.Read())
            {
            txtName.Text = rdr[1].ToString();
            txtAge.Text = rdr[2].ToString();
            txtGender.Text = rdr[3].ToString();
            txtCity.Text = rdr[4].ToString();
            }
            }
            else
            {
            MessageBox.Show("User ID doesn't exist!", "info", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            }
            }

            private void btnDelete_Click(object sender, EventArgs e)
            {
            conn = new SqlConnection(CS);
            conn.Open();

            if (txtSearch.Text == string.Empty)
            {
            MessageBox.Show("Please enter the ID to be deleted!", "info", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            else
            {
            try
            {
            DialogResult d = MessageBox.Show("Do you want to Delete User having ID " + txtSearch.Text, "Inform", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
            if (d == DialogResult.Yes)
            {
            cmd = new SqlCommand("delete from tblInformation where ID='" + txtSearch.Text + "'", conn);
            cmd.CommandType = CommandType.Text;
            cmd.ExecuteNonQuery();
            MessageBox.Show("Record deleted successfully!", "Delete", MessageBoxButtons.OK, MessageBoxIcon.Information);
            ClearFields();

            DataTable dt = new DataTable();
            da = new SqlDataAdapter("select * from tblInformation ", conn);
            da.Fill(dt);
            dataGridView1.DataSource = dt;
            }
            }
            catch (Exception ex)
            {
            MessageBox.Show(ex.Message);
            }
            }
            }
            }
            }