Export to xls file with count or date time

Question

I'm trying to export my datagridview data to excel file using streamWriter it works fine but when export second time it replace the old file.

Here my code

 private void button1_Click(object sender, EventArgs e)
        {
                if (dataGridView1.Rows.Count > 0)
                {
                    try
                    {
                        // Bind Grid Data to Datatable
                        DataTable dt = new DataTable();
                        foreach (DataGridViewColumn col in dataGridView1.Columns)
                        {
                            dt.Columns.Add(col.HeaderText, col.ValueType);
                        }
                        int count = 0;
                        foreach (DataGridViewRow row in dataGridView1.Rows)
                        {
                            if (count < dataGridView1.Rows.Count - 1)
                            {
                                dt.Rows.Add();
                                foreach (DataGridViewCell cell in row.Cells)
                                {
                                    dt.Rows[dt.Rows.Count - 1][cell.ColumnIndex] = cell.Value.ToString();
                                }
                            }
                            count++;
                        }
                        DateTime now = DateTime.Now;
                        int hour = now.Hour;
                        int minute = now.Minute;
                        int second = now.Second;
                        int month = now.Month;
                        int day = now.Day;
                        int year = now.Year;
                        // Bind table data to Stream Writer to export data to respective folder
                        StreamWriter wr = new StreamWriter(@"C:\Users\admin\Downloads\\Book1.xls");
                        // Write Columns to excel file
                        for (int i = 0; i < dt.Columns.Count; i++)
                        {
                            wr.Write(dt.Columns[i].ToString().ToUpper() + "\t");
                        }
                        wr.WriteLine();
                        //write rows to excel file
                        for (int i = 0; i < (dt.Rows.Count); i++)
                        {
                            for (int j = 0; j < dt.Columns.Count; j++)
                            {
                                if (dt.Rows[i][j] != null)
                                {
                                    wr.Write(Convert.ToString(dt.Rows[i][j]) + "\t");
                                }
                                else
                                {
                                    wr.Write("\t");
                                }
                            }
                            wr.WriteLine();
                        }
                        wr.Close();
                        MessageBox.Show("Data Exported Successfully");
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }
                }
                else
                {
                    MessageBox.Show("No data found");
                }
        } 

I'm trying to add date time in the file name

                    StreamWriter wr = new StreamWriter(@"C:\Users\admin\Downloads\\Extension Report Time", hour, " - ", minute, " - ", second".xls");

but it get error message

StreamWriter does not contain a constructor that takes 7 arugements

Answer 1

Try an interpolated string:

StreamWriter wr = new StreamWriter($"C:\\Users\\admin\\Downloads\\Extension Report Time {hour}-{minute}-{second}.xls");