How to: Filter Files to Archive

• Apr 05, 2019
• 2 minutes to read

To only archive files that meet a certain criteria, do the following:

1. Create a ZipArchive class instance.
2. Subscribe to its ZipArchive.ItemAdding event. This event is raised for each ZipItem that holds information for a file or directory. Add event handler code to analyze the ZipItem and specify the action to perform – to continue archiving, to stop the process or to cancel adding this particular item to an archive.
3. Call the ZipArchive.AddFile method for each selected file.
4. Call the ZipArchive.Save method to create an archive and save it to a specified location.

This example demonstrates how to handle the ZipArchive.ItemAdding event to decide for each file whether it should be included in the archive.

If a file creation date is not the current date, the file is not added to the archive. A volatile variable is used to indicate whether the process should be stopped - it can be useful to interrupt archive creation if too many files are specified.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/compression-library-examples-e4695

ZipExamples.cs

using DevExpress.Compression;
        volatile bool stopArchiving = false;
        public void FilterArchiveFiles() {
            string[] sourcefiles = this.sourceFiles;
            using (ZipArchive archive = new ZipArchive()) {
                archive.ItemAdding += archive_ItemAdding;
                foreach (string file in sourceFiles) {
                    archive.AddFile(file, "/");
                }
                archive.Save("Documents\\FilterArchiveFiles.zip");
            }
        }

        private void archive_ItemAdding(object sender, ZipItemAddingEventArgs args) {
            if (args.Item.CreationTime.Date != DateTime.Today)
                args.Action = ZipItemAddingAction.Cancel;
            if (stopArchiving) args.Action = ZipItemAddingAction.Stop;
        }

ZipExamples.vb

Imports DevExpress.Compression
'INSTANT VB TODO TASK: There is no VB.NET equivalent to 'volatile':
'ORIGINAL LINE: volatile bool stopArchiving = False;
        Private stopArchiving As Boolean = False
        Public Sub FilterArchiveFiles()
            Dim sourcefiles() As String = Me.sourceFiles
            Using archive As New ZipArchive()
                AddHandler archive.ItemAdding, AddressOf archive_ItemAdding
                For Each file As String In Me.sourceFiles
                    archive.AddFile(file, "/")
                Next file
                archive.Save("Documents\FilterArchiveFiles.zip")
            End Using
        End Sub

        Private Sub archive_ItemAdding(ByVal sender As Object, ByVal args As ZipItemAddingEventArgs)
            If args.Item.CreationTime.Date <> DateTime.Today Then
                args.Action = ZipItemAddingAction.Cancel
            End If
            If stopArchiving Then
                args.Action = ZipItemAddingAction.Stop
            End If
        End Sub