Inserting & Retrieving records from MS Excel 2003 using OLEDB

Objective

To develop a Windows application using C#.Net to insert, search, and update records from M.S.Excel-2003 file using OleDb Connection.

Design

Design the form as above with a DataGridView,3 Labels, 3 TextBoxes, and 9 buttons.

Introduction

As we want to use OleDb Connection include the namespace:'usingSystem.Data.OleDb'

For accessing records from the M.S.Excel-2003 file, we use the 'Jet' driver.

In this application, we will search a record by taking input from the InputBox. For this, we have to add a reference to Microsoft.VisualBasic.

Adding reference to Microsoft.VisualBasic

• Goto Project Menu->Add Reference -> select 'Microsoft.VisualBasic' from the .NET tab.
• To use this we have to include the namespace:'usingMicrosoft.VisualBasic'.

Creating a primary key in the data table

In this app., we use the Find() method to search a record, which requires details of the primary-key column. Database tables are provided using the statement.

adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey

However since we don't have any primary key column in the M.S. Excel table, we have to create a primary key column in the data table.

Eg

ds.Tables[0].Constraints.Add("pk_sno", ds.Tables[0].Columns[0], true);

Pointing to the current record in Table

After searching for a record, we have to get the index of that record so that we can navigate the next and previous records.

Eg

rno = ds.Tables[0].Rows.IndexOf(drow);

Code

using System;
using System.Data;
using System.Data.OleDb;
using System.Windows.Forms;
using Microsoft.VisualBasic;
namespace xloledb03
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        OleDbConnection con;
        OleDbCommand cmd;
        OleDbDataAdapter da;
        DataSet ds;
        int rno = 0;
        private void Form1_Load(object sender, EventArgs e)
        {
            con = new OleDbConnection(@"Provider=Microsoft.Jet.Oledb.4.0;data source=E:\prash\xldb.xls;Extended Properties=""Excel 8.0;HDR=Yes;"" ");
            loaddata();
            showdata();
        }
        void loaddata()
        {
            da = new OleDbDataAdapter("select * from [student$]", con);
            ds = new DataSet();
            da.Fill(ds, "student");
            ds.Tables[0].Constraints.Add("pk_sno", ds.Tables[0].Columns[0], true);
            dataGridView1.DataSource = ds.Tables[0];
        }
        void showdata()
        {
            textBox1.Text = ds.Tables[0].Rows[rno][0].ToString();
            textBox2.Text = ds.Tables[0].Rows[rno][1].ToString();
            textBox3.Text = ds.Tables[0].Rows[rno][2].ToString();
        }
        private void btnInsert_Click(object sender, EventArgs e)
        {
            cmd = new OleDbCommand("insert into [student$] values(" + textBox1.Text + ",' " + textBox2.Text + " ',' " + textBox3.Text + " ')", con);
            con.Open();
            int n = cmd.ExecuteNonQuery();
            con.Close();
            if (n > 0)
            {
                MessageBox.Show("record inserted");
                loaddata();
            }
            else
                MessageBox.Show("insertion failed");
        }
        private void btnSearch_Click(object sender, EventArgs e)
        {
            int n = Convert.ToInt32(Interaction.InputBox("Enter sno:", "Search", "20", 200, 200));
            DataRow drow = ds.Tables[0].Rows.Find(n);
            if (drow != null)
            {
                textBox1.Text = drow[0].ToString();
                textBox2.Text = drow[1].ToString();
                textBox3.Text = drow[2].ToString();
            }
            else
                MessageBox.Show("Record not found");
        }
        private void btnUpdate_Click(object sender, EventArgs e)
        {
            cmd = new OleDbCommand(" update [student$] set sname='" + textBox2.Text + "',course='" + textBox3.Text + "' where sno=" + textBox1.Text + " ", con);
            con.Open();
            int n = cmd.ExecuteNonQuery();
            con.Close();
            if (n > 0)
            {
                MessageBox.Show("Record Updated");
                loaddata();
            }
            else
                MessageBox.Show("Update failed");
        }
        private void btnFirst_Click(object sender, EventArgs e)
        {
            if (ds.Tables[0].Rows.Count > 0)
            {
                rno = 0;
                showdata();
                MessageBox.Show("First Record");
            }
            else
                MessageBox.Show("no records");
        }
        private void btnPrevious_Click(object sender, EventArgs e)
        {
            if (ds.Tables[0].Rows.Count > 0)
            {
                if (rno > 0)
                {
                    rno--;
                    showdata();
                }
                else
                    MessageBox.Show("First Record");
            }
            else
                MessageBox.Show("no records");
        }
        private void btnNext_Click(object sender, EventArgs e)
        {
            if (ds.Tables[0].Rows.Count > 0)
            {
                if (rno < ds.Tables[0].Rows.Count - 1)
                {
                    rno++;
                    showdata();
                }
                else
                    MessageBox.Show("Last Record");
            }
            else
                MessageBox.Show("no records");
        }
        private void btnLast_Click(object sender, EventArgs e)
        {
            if (ds.Tables[0].Rows.Count > 0)
            {
                rno = ds.Tables[0].Rows.Count - 1;
                showdata();
                MessageBox.Show("Last Record");
            }
            else
                MessageBox.Show("no records");
        }
        private void btnClear_Click(object sender, EventArgs e)
        {
            textBox1.Text = textBox2.Text = textBox3.Text = "";
        }
        private void btnExit_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    }
}

Note. The 'xldb.xls' file is provided in the xloledb03.zip file along with the source code.