read the data from the Excel sheet and display the result into a repeater control

using System;

using System.Data;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Data.OleDb;

public partial class _Default : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        if (!IsPostBack)

            BindRepeater();

    }

    private DataTable ReadExcelData(Int32 UserID)

    {

        string file = Server.MapPath("UserData.xls");

        string constr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + file + ";Extended Properties=Excel 8.0;";

       

        string query = "Select UserID,UserName,Country,State,City from [Sheet1$]";

        if (UserID > 0)

            query = query + " WHERE UserID=" + UserID.ToString();

        DataSet dsUserData = new DataSet();

        using (OleDbConnection Connection = new OleDbConnection(constr))

        {

            using (OleDbDataAdapter DataAdapter = new OleDbDataAdapter(query, Connection))

            {

                DataAdapter.Fill(dsUserData, "UserData");

                DataAdapter.AcceptChangesDuringFill = false;

                DataAdapter.Dispose();

                Connection.Close();

            }

        }

        return dsUserData.Tables[0];

    }

    private void BindRepeater()

    {

        rptUserData.DataSource = ReadExcelData(-1);

        rptUserData.DataBind();

    }

    protected void rptUserData_ItemCommand(object source, RepeaterCommandEventArgs e)

    {

        if (e.CommandName == "Edit")

        {

            DataTable dtData= ReadExcelData(Convert.ToInt32(e.CommandArgument));

            if (dtData.Rows.Count > 0)

            {

                txtUserName.Text = dtData.Rows[0]["UserName"].ToString();

                txtCountry.Text = dtData.Rows[0]["Country"].ToString();

                txtState.Text = dtData.Rows[0]["State"].ToString();

                txtCity.Text = dtData.Rows[0]["City"].ToString();

                btnUpdate.CommandArgument = dtData.Rows[0]["UserID"].ToString();

                btnUpdate.Visible = true;

                btnInsert.Visible = false;

                divInsertUpdate.Visible = true;

            }

        }

    }

    protected void lnkInsert_Click(object sender, EventArgs e)

    {

        btnUpdate.Visible = false;

        btnInsert.Visible = true;

        divInsertUpdate.Visible = true;

    }

    protected void btnInsert_Click(object sender, EventArgs e)

    {

        Int32 LastUserID = Convert.ToInt32(((Label)rptUserData.Items[rptUserData.Items.Count - 1].FindControl("lblID")).Text);

        LastUserID += 1;

        string file = Server.MapPath("UserData.xls");

        string constr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + file + ";Extended Properties=Excel 8.0;";

        using (OleDbConnection Connection = new OleDbConnection(constr))

        {

            Connection.Open();

            string query = "INSERT INTO [Sheet1$](UserID,UserName,Country,State,City) VALUES(" + LastUserID + ",\"" + txtUserName.Text.Trim() + "\",\"" + txtCountry.Text.Trim() + "\",\"" + txtState.Text.Trim() + "\",\"" + txtCity.Text.Trim() + "\")";

            using (OleDbCommand objCmd = new OleDbCommand(query, Connection))

            {

                objCmd.ExecuteNonQuery();

                objCmd.Dispose();

                Connection.Close();

            }

        }

        BindRepeater();

        divInsertUpdate.Visible = false;

    }

    private void UpdateRecord()

    {

        string file = Server.MapPath("UserData.xls");

        string constr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + file + ";Extended Properties=Excel 8.0;";

        using (OleDbConnection Connection = new OleDbConnection(constr))

        {

            Connection.Open();

            string query = "UPDATE [Sheet1$] SET UserName=\"" + txtUserName.Text.Trim() + "\",Country=\"" + txtCountry.Text.Trim() + "\",State=\"" + txtState.Text.Trim() + "\",City=\"" + txtCity.Text.Trim() + "\" WHERE UserID="+ btnUpdate.CommandArgument.ToString();

            using (OleDbCommand objCmd = new OleDbCommand(query, Connection))

            {

                objCmd.ExecuteNonQuery();

                objCmd.Dispose();

                Connection.Close();

            }

        }

    }

    protected void btnUpdate_Click(object sender, EventArgs e)

    {

        UpdateRecord();

        BindRepeater();

        divInsertUpdate.Visible = false;

    }

}

The following code sample shows how to check whether the textbox have only numbers.
int a=0;
foreach(string s in textbox1.text)
{
a=s;
if ((s>65 && s<90) || (s>97 && s<122))
{
messagebox.show("Characters are not allowed");
}
}
//using the ascii values we checking whether the values present in the textbox is character or numbers.