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Monday 20 March 2017

On 21:22 by Vardan Kumar in    13 comments
File Versioning C#

File versioning, saving file with unique file name in c#

File versioning allows a user to have several versions of a file simultaneously at a particular path. Not only it intimates a user of which is the latest version i.e generated at a later stage or an older version but also provides a unique file name in the same directory.

For example....

Suppose a report generation application is developed which saves a user-readable file as an output, as discussed in earlier posts also an efficient GUI(Graphical user interface) is the most interactive one i.e. a GUI in which a user feels to have control over the application. In such an application a user is generally provided with the privilege to select his/her desired path. It is a general tendency of a computer operating individual to select same path as well as name each time he/she wants to generate the report. Now suppose user chooses a file name as cspassion.xlsx and the same file name already exists at that path, so an efficient application would save the latest version of report as cspassion(1).xlsx or cspassion(2).xlsx to avoid exception or prompting user to select if he/she wants to replace the previous version of file or not, also this would take the control from your application to the operating system which should generally be avoided as much as possible.

Logic

  • First of all user selected file name or path is sent as an argument to the method fetching unique file path or creating file versions.
  • Now we will check if the file already exists at that directory or not
    • If not then return that file path and save the file with user selected file name at his/her desired path.
    • If yes then continue with the version generation.
  • Now split and store directory,file name as well as extension in different identifiers.
  • Initialize number as 1,if you want to display (2) as file version after first version and initialize to 0 if you want it as (1) after first version.
  • Now we'll check if a version after initial version is generated using regular expression match
    • If it matches then we'll extract file name from group 1 and number from group 2.
  • Now we have number as well as file name we'll loop through while the file exists in that path.
    • We'll increment number by 1 in each iteration
    • Format the string as filename,(number) and extension. 
  • Return the file path and save the workbook.
I have generated five versions of same file named cspassion for reference in current directory. Refer to image below


File Versioning, unique file path c#
File Versioning C#

Source Code

using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Microsoft.Office.Interop.Excel;
using Oracle.DataAccess.Client;
using System.Configuration;
using System.Text.RegularExpressions;
using System.Xml;
using System.IO;

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
string s_oRcConnectionString = null; //Click here to know how to set dynamic connection string c#
        ToolTip tt = new ToolTip();
        string uniquepath=String.Empty;
private void btn_Save(object sender, EventArgs e)
{
             xlWorkbook.SaveAs(uniquepath);
}
private void btn_Browse_Click_1(object sender, EventArgs e)
        {
            SaveFileDialog saveFileDialog1 = new SaveFileDialog();// using save file dialog
            saveFileDialog1.Filter = "Excel|*.xlsx";
            saveFileDialog1.Title = "Save Excel report";
            if (saveFileDialog1.ShowDialog() == DialogResult.OK)
            lbl_Path.Text = saveFileDialog1.FileName;
            tt.SetToolTip(lbl_Path, lbl_Path.Text);   // click here to read how to set tool tip for controls
            lbl_Path.Visible = true;
            string path=lbl_Path.Text;
            uniquepath=GetUniqueFilePath(path);
            
        }              
                    
public static string GetUniqueFilePath(string filepath)
        {
            if (File.Exists(filepath))
            {
                string fold = Path.GetDirectoryName(filepath);
                string filename = Path.GetFileNameWithoutExtension(filepath);
                string extension = Path.GetExtension(filepath);
                int number = 1;

                Match regex = Regex.Match(filepath, @"(.+) \((\d+)\)\.\w+");

                if (regex.Success)
                {
                    filename = regex.Groups[1].Value;
                    number = int.Parse(regex.Groups[2].Value);
                }

                do
                {
                    number++;
                    filepath = Path.Combine(folder, string.Format("{0} ({1}){2}", filename, number, extension));
                }
                while (File.Exists(filepath));
            }

            return filepath;
        }
    }
}

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