Question

Hi all i am having a list box on my Form which will display all the .txt files from the directory C:. This list box selection mode is set to MultiExtended.

My condition to check whether the file is valid or not will be checked using the condition as each and every line content of the selected file should be *94*. If this one satisifes then only it is said to be a valid file. I have written a code for this too but as i am checking in the loop and at a time i can only read one file content this was working fine. But i have to check initially all the selected files matches the condition or not if ok then i have to do the remaining code if not i would like to display error

My code on Button Click

  private void btnMerge_Click(object sender, EventArgs e)
    {
        if (lstACH.SelectedIndices.Count == 1)
        {
            MessageBox.Show("Select 2 Files To Merge");
        }
        else
        {
            for (i = 0; i < lstACH.SelectedItems.Count; i++)
            {
                strFile = lstACH.SelectedItems[i].ToString();
                lines = File.ReadAllLines(strFile);
                if (LinesHaveCorrectLength(lines, 94)) // Here i am checking but at a tym i am checking one file only i have to check for all and if ok then the remaining code has to be executed
                {
                    if (i == 0)
                    {
                        Stream myStream;

                        SaveFileDialog saveFileDialog1 = new SaveFileDialog();

                        saveFileDialog1.InitialDirectory = @"C:\";
                        saveFileDialog1.DefaultExt = "txt";
                        saveFileDialog1.Filter = "(*.txt)|*.txt";
                        saveFileDialog1.FilterIndex = 2;
                        saveFileDialog1.RestoreDirectory = true;
                        saveFileDialog1.ValidateNames = true;
                        if (saveFileDialog1.ShowDialog() == DialogResult.OK)
                        {
                            Append.FileName = saveFileDialog1.FileName;
                            if (Append.FileName.Contains(" \\/:*?<>|"))
                            {
                                MessageBox.Show("File name should not contain \\/:*?<>|", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
                            }
                            else
                            {
                                if ((myStream = saveFileDialog1.OpenFile()) != null)
                                {
                                    Append.FileName = saveFileDialog1.FileName;
                                    myStream.Close();
                                }
                            }
                        }
                    }
                    using (StreamWriter sw = new StreamWriter(Append.FileName, true))
                    {
                        using (StreamReader srBatch = new StreamReader(strFile))
                        {
                            while (srBatch.Peek() >= 0)
                            {
                                strReadLine = srBatch.ReadLine();
                                if (strReadLine.StartsWith("1"))
                                {
                                    if (i == 0)
                                    {
                                        strFileHeader = strReadLine;
                                        sw.WriteLine(strFileHeader);
                                    }
                                }
                                if (strReadLine.StartsWith("5"))
                                {
                                    strBtchHeader = strReadLine;
                                    if (i == 0)
                                    {
                                        Btchno = Convert.ToInt32(strReadLine.Substring(87, 7));
                                        BatchCnt = Convert.ToInt16(Btchno);
                                    }
                                    if (i > 0)
                                    {
                                        BatchCnt++;
                                        strBtchHeader = strBtchHeader.Substring(0, 87) + Convert.ToString(BatchCnt.ToString().PadLeft(7, (char)48));
                                    }
                                    sw.WriteLine(strBtchHeader);
                                }
                                if (strReadLine.StartsWith("6"))
                                {
                                    strEntryDetail = strReadLine;
                                    if (i == 0)
                                    {
                                        strTraceNo = strEntryDetail.Substring(87, 7);
                                        EntryCount = Convert.ToInt16(strTraceNo);
                                    }
                                    if (i > 0)
                                    {
                                        EntryCount++;
                                        strEntryDetail = strEntryDetail.Substring(0, 87) + EntryCount.ToString().PadLeft(7, (char)48);
                                    }
                                    sw.WriteLine(strEntryDetail);
                                }
                                if (strReadLine.StartsWith("8"))
                                {
                                    strBtchCntrl = strReadLine;
                                    if (i > 0)
                                    {
                                        //btchEntry++;
                                        strBtchCntrl = strBtchCntrl.Substring(0, 87) + BatchCnt.ToString().PadLeft(7, (char)48);
                                    }
                                    sw.WriteLine(strBtchCntrl);
                                }
                                if (strReadLine.StartsWith("9"))
                                {
                                    strFileCntrl = strReadLine;

                                    strBtchCnt = strReadLine.Substring(1, 6);
                                    strEntrycnt = strReadLine.Substring(13, 8);
                                    strEntryHash = strReadLine.Substring(21, 10);
                                    strDebitAmnt = strReadLine.Substring(31, 12);
                                    strCreditAmnt = strReadLine.Substring(43, 12);

                                    BtchCnt += Convert.ToDouble(strBtchCnt);
                                    Entrycnt += Convert.ToDouble(strEntrycnt);
                                    EntryHash += Convert.ToDouble(strEntryHash);
                                    DebitAmnt += Convert.ToDouble(strDebitAmnt);
                                    CreditAmnt += Convert.ToDouble(strCreditAmnt);

                                    if (i == lstACH.SelectedItems.Count - 1)
                                    {
                                        strFileCntrl = strFileCntrl.Substring(0, 1) + BtchCnt.ToString().PadLeft(6, (char)48) + strFileCntrl.Substring(7, (strFileCntrl.Length - 7));
                                        strFileCntrl = strFileCntrl.Substring(0, 13) + Entrycnt.ToString().PadLeft(8, (char)48) + strFileCntrl.Substring(21, (strFileCntrl.Length - 21));
                                        strFileCntrl = strFileCntrl.Substring(0, 21) + EntryHash.ToString().PadLeft(10, (char)48) + strFileCntrl.Substring(31, (strFileCntrl.Length - 31));
                                        strFileCntrl = strFileCntrl.Substring(0, 31) + DebitAmnt.ToString().PadLeft(12, (char)48) + strFileCntrl.Substring(43, (strFileCntrl.Length - 43));
                                        strFileCntrl = strFileCntrl.Substring(0, 43) + CreditAmnt.ToString().PadLeft(12, (char)48) + strFileCntrl.Substring(55, (strFileCntrl.Length - 55));
                                        sw.WriteLine(strFileCntrl);
                                    }
                                }
                            }
                        }
                    }
                    if (i == lstACH.SelectedItems.Count - 1)
                    {
                        MessageBox.Show("File Has Been Merged Successfully");
                        this.Close();
                    }
                }
                else
                {
                    MessageBox.Show("One of the Selected File is not a Valid ACH File");
                    break;
                }
            }
        }
    }

Checking for Each and every line Length

 private static bool LinesHaveCorrectLength(string[] lines, int expectedLineLength)
    {
        foreach (string item in lines)
        {
            if (item.Length != expectedLineLength)
            {
                return false;
            }
        }
        return true;
    }

Answer 1

Just check them all first – and if all good, THEN begin merge.

        if (lstACH.SelectedIndices.Count != 2)
        {
            MessageBox.Show("Select 2 Files To Merge");
            return;
        }

        foreach (String fileName in lstACH.SelectedItems)
        {
            if( LinesHaveCorrectLength( File.ReadAllLines(fileName), 94 ) == false )
            {
                MessageBox.Show("File: " + fileName + " has an incorrect line length");
                return;
            }
        }

        // Now process them all again to merge:
        foreach(String fileName in lstACH.SelectedItems)
        {
            // ... do merge logic
        }