protected void Button_Click(object sender, EventArgs e)
{
if (((Button)sender).ID == "reset")
{ TextBox1.Text = ""; }
else
{
Submit();
}

}

protected void Submit()
{
OleDbCommand OleCmd;
OleDbConnection conn;
string strCommand;

conn = new OleDbConnection("Provider=Microsoft.Jet.OleDb.4.0;Data Source=f:\\Data\\image.mdb");
strCommand = "Select UserEmain From Dv_User Where UserName=@txtUserName";
OleCmd = new OleDbCommand(strCommand,conn);
OleCmd.Parameters.Add("@txtUserName", TextBox1.Text);
conn.Open();

object resoult = OleCmd.ExecuteScalar();
if (resoult == null)
{
TextBox2.Text = "Not Found!";
}
else
{
TextBox2.Text= resoult.ToString();
}

}