- VB.NET FILE MONITOR WATCHER CHANGE JOURNAL HOW TO
- VB.NET FILE MONITOR WATCHER CHANGE JOURNAL WINDOWS
MessageBox.Show("Please select a valid file to compute the hash for.") ' Save the file name so we can check later. If Not String.IsNullOrEmpty(dlgOpenFile.FileName) Then If dlgOpenFile.ShowDialog() = DialogResult.OK Then Private Sub btnSelectFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSelectFile.Click ' Select file button opens a file dialog to select a file to check.
VB.NET FILE MONITOR WATCHER CHANGE JOURNAL WINDOWS
We could even sort the array and check files based on an ascending file name order or sort based on some other attribute like file modified or create date.īelow is one simple windows application in VB.NET where we have three buttons. Now if we wanted to take this to the next level we could simply open several files and store the hashes in an array (along with the path to the file so we know which hash belongs to which file) and compare them again later. The third and last phase is to check the file for a change by opening that same file, recomputing the hash and comparing it to the one we saved. Whatever that hash is, we save it along with the location of the file for convenience. This file could be a text file or a binary file, doesn’t matter. Second we want to open that file and generate a hash based on its contents.
To start off, we want to be able to do three things in our example program.
VB.NET FILE MONITOR WATCHER CHANGE JOURNAL HOW TO
We will show you how to use a simple file hash to check for such changes in VB.NET on this entry of the Programming Underground! The idea below can be scaled up to monitor several files for a small change or check for file changes on your schedule. However, you may want something with a more simple concept. This might be a good approach for more elaborate programs where you also want to watch the creation/deletion of files, monitor more than one file or watch an entire directory. One way you could do this is by hooking up a FileSystemWatcher object and monitor the file. Perhaps you are monitoring a log file or checking to see if an exe has had a virus mess with it. Once in awhile you may want to check if a file has changed its contents in some way.
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