CRUD Operation using C# Programming Language

The following source code performs CRUD operation using C# programming language. In addition, search function also added in this source code.

This code used for my future reference. I hope it could be helpful also. Thank you



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.OleDb;
namespace CRUD_Application_CSharp
{
    public partial class Form1 : Form
    {
        String connectionString;
        OleDbConnection conn;
        OleDbDataAdapter da;
        OleDbCommand cmd;
        //DataSet ds;
        string sql;
        public int x;

        public Form1()
        {
            InitializeComponent();
        }
        public void dbConnection()
        {

            connectionString = @"Provider=Microsoft.JET.OLEDB.4.0;Data Source=C:\\Users\Juno\Documents\dbInformation.mdb";
            conn = new OleDbConnection(connectionString);
            conn.Open();
            //MessageBox.Show("Connection Open  !");
            //conn.Close();
        }

        private void btnReadDatabase_Click(object sender, EventArgs e)
        {
     
            retrieveALL();

        }
        private void retrieveALL(){
             dbConnection();
            sql = "SELECT * FROM tblProfile";
            da = new OleDbDataAdapter(sql, conn);
            DataTable dt = new DataTable();      //ds = new DataSet();
            da.Fill(dt);                         //da.Fill(ds, "dbInformation");
            dataGridView1.DataSource = dt;       //dataGridView1.DataSource = ds.Tables[0];
            conn.Close();
        }
        private void btnSave_Click(object sender, EventArgs e)
        {

            dbConnection();
            sql = "INSERT INTO tblProfile (Firstname,Lastname,Gender) VALUES ('" + txtFname.Text + "','" + txtLname.Text + "','" + cbGender.Text + "')";
            cmd = new OleDbCommand(sql, conn);
            cmd.ExecuteNonQuery();
            MessageBox.Show("Successfully Added to your Database", "New Record Added", MessageBoxButtons.OK, MessageBoxIcon.Information);
            conn.Close();

            //btnReadDatabase_Click(sender, e);
            retrieveALL();
        }
        private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
        {
           
            x = dataGridView1.Rows.IndexOf(dataGridView1.CurrentRow);

            txtFname.Text = dataGridView1.Rows[x].Cells[1].Value.ToString();
            txtLname.Text = dataGridView1.Rows[x].Cells[2].Value.ToString();
            cbGender.Text = dataGridView1.Rows[x].Cells[3].Value.ToString();
            MessageBox.Show(dataGridView1.Rows[x].Cells[0].Value.ToString());

        }

        private void btnUpdate_Click(object sender, EventArgs e)
        {
            dbConnection();
            int indexID;
            x = dataGridView1.Rows.IndexOf(dataGridView1.CurrentRow);
            indexID =  Convert.ToInt32((dataGridView1.Rows[x].Cells[0].Value.ToString()));

            sql = "UPDATE tblProfile SET Firstname= '" + txtFname.Text + "',Lastname='" + txtLname.Text +
                "',Gender='" + cbGender.Text + "' WHERE ID=" + indexID + "";

            cmd = new OleDbCommand(sql, conn);
            cmd.ExecuteNonQuery();
            MessageBox.Show("Successfully Updated...", "Update");
            conn.Close();

            //btnReadDatabase_Click(sender, e);
            retrieveALL();
        }

        private void btnDelete_Click(object sender, EventArgs e)
        {
            dbConnection();
            int indexID;
            x = dataGridView1.Rows.IndexOf(dataGridView1.CurrentRow);
            indexID = Convert.ToInt32((dataGridView1.Rows[x].Cells[0].Value.ToString()));

            sql = "DELETE FROM tblProfile WHERE ID=" + indexID + "";

            cmd = new OleDbCommand(sql, conn);
            cmd.ExecuteNonQuery();
            MessageBox.Show("Successfully Deleted...", "Delete");
            conn.Close();
            retrieveALL();
        }

        private void btnSearch_Click(object sender, EventArgs e)
        {
            dbConnection();
            sql = "SELECT * FROM tblProfile WHERE Firstname='" + txtSearch.Text+ "' OR Lastname='" + txtSearch.Text +"'";
            da = new OleDbDataAdapter(sql, conn);
            DataTable dt = new DataTable();      //ds = new DataSet();
            da.Fill(dt);                         //da.Fill(ds, "dbInformation");
            dataGridView1.DataSource = dt;       //dataGridView1.DataSource = ds.Tables[0];
            conn.Close();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            dataGridView2.Columns.Add("Firstname","fname");
            dataGridView2.Columns.Add("Lastname","lname");
            dataGridView2.Columns.Add("Gender","gender");
            retrieveALL();
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            txtFname.Clear();
            txtLname.Clear();
            txtSearch.Clear();
            cbGender.Text = null;
        }

        private void button1_Click(object sender, EventArgs e)
        {

           
            for (int i = 0; i < dataGridView2.Rows.Count; i++)
            {
                sql = @"INSERT INTO tblProfile (Firstname,Lastname,Gender) VALUES ('"
                    + dataGridView2.Rows[i].Cells["Firstname"].Value + "',' "
                    + dataGridView2.Rows[i].Cells["Lastname"].Value + "', '"
                    + dataGridView2.Rows[i].Cells["Gender"].Value + "')";
                dbConnection();
                cmd = new OleDbCommand(sql, conn);
                cmd.ExecuteNonQuery();

                MessageBox.Show("Successfully Added to your Database", "New Record Added", MessageBoxButtons.OK, MessageBoxIcon.Information);
                conn.Close();

                //btnReadDatabase_Click(sender, e);
                retrieveALL();
            }
        }
    }
}