Ka darau negerai, kad man ismeta klaida: "nKindly Check Worksheet Name" ? 
Gal yra algoritme klaidu, nes EXCEL sheeto pavadinimas butent "Sheet1".
Ka ismesti is sio algoritmo, kad isvis nieko netikrintu o tik importuotu 
duomenis i datagrida. Bandau pratrinti tai kas yra po IF, bet po to labai 
daug ivairiausiu klaidu ismeta.


        private void button3_Click_1(object sender, EventArgs e)
        {
            int rows_counting, column_counting1 = 0;
            OpenFileDialog dialog = new OpenFileDialog { };
            dialog.Filter = "Sending File(*.xlsx;*.xls)|*.xlsx;*.xls";
            dialog.Title = "Select File";
            DialogResult dlgresult = dialog.ShowDialog();
            if (dlgresult == DialogResult.Cancel)
            {
                MessageBox.Show("You Press Cancelled :-) !!!");
            }
            else
            {
                string filename = dialog.FileName;

                if (System.IO.File.Exists(filename))
                {
                    try
                    {
                        Cursor.Current = Cursors.WaitCursor;
                        string connectionString = 
String.Format(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended 
Properties=""Excel 8.0;HDR=YES;IMEX=1;""", filename);
                        string query = String.Format("select * from [{0}$]", 
"Sheet1");
                        OleDbDataAdapter dataAdapter = new 
OleDbDataAdapter(query, connectionString);
                        dataSet = new DataSet();
                        dataAdapter.Fill(dataSet);
                        dataGridView1.DataSource = dataSet.Tables[0];
                        dataGridView1.AutoSizeColumnsMode = 
DataGridViewAutoSizeColumnsMode.DisplayedCells;
                        rows_counting = dataGridView1.RowCount - 1;
                        column_counting1 = dataGridView1.ColumnCount;
                        if (column_counting1 < 2 || column_counting1 > 2)
                        {
                            MessageBox.Show("Kindly Check Column Count in 
Excel Sheet !!!\r\n\nThere Should Be Only Two Columns in Sheet Like 
Below\r\n\nNAME | ADDRESS", "Error", MessageBoxButtons.OK, 
MessageBoxIcon.Error);
                            return;
                        }
                        if ( 
dataGridView1.Columns[0].Name.ToString().ToUpper() == "NAME" &&
                                dataGridView1.Columns[1].Name.ToString().ToUpper() 
== "ADDRESS")
                        {
                            label25.Text = "Total Records In Excel File " + 
rows_counting;
                            MessageBox.Show("Data Imported 
Successfully...!!!\r\n\nCheck Imported Values & ADDRESS!", "Information", 
MessageBoxButtons.OK, MessageBoxIcon.Information);
                            button7.Enabled = true;
                            button4.Enabled = true;
                            Cursor.Current = Cursors.Default;
                        }
                        else
                        {
                            MessageBox.Show("Column Names Are Not In 
Specified Format !!!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                            return;
                        }
                    }
                    catch (Exception E6)
                    {
                        MessageBox.Show("Error Loading Excel 
FIle\r\n\nKindly Check Worksheet Name", "Error", MessageBoxButtons.OK, 
MessageBoxIcon.Error);
                        return;
                    }
                }
            }
        }