Can't get my head around background workers in .NET
- by Connel
I have wrote an application that syncs two folders together. The problem with the program is that it stops responding whilst copying files. A quick search of stack-overflow told me I need to use something called a background worker. I have read a few pages on the net about this but find it really hard to understand as I'm pretty new to programming. Below is the code for my application - how can I simply put all of the File.Copy(....) commands into their own background worker (if that's even how it works)? Below is the code for the button click event that runs the sub procedure and the sub procedure I wish to use a background worker on all the File.Copy lines.
Button event:
protected virtual void OnBtnSyncClicked (object sender, System.EventArgs e)
{
//sets running boolean to true
booRunning=true;
//sets progress bar to 0
prgProgressBar.Fraction = 0;
//resets values used by progressbar
dblCurrentStatus = 0;
dblFolderSize = 0;
//tests if user has entered the same folder for both target and destination
if (fchDestination.CurrentFolder == fchTarget.CurrentFolder) {
//creates message box
MessageDialog msdSame = new MessageDialog(this, DialogFlags.Modal, MessageType.Error, ButtonsType.Close, "You cannot sync two folders that are the same");
//sets message box title
msdSame.Title="Error";
//sets respone type
ResponseType response = (ResponseType) msdSame.Run();
//if user clicks on close button or closes window then close message box
if (response == ResponseType.Close || response == ResponseType.DeleteEvent) {
msdSame.Destroy();
}
return;
}
//tests if user has entered a target folder that is an extension of the destination folder
// or if user has entered a desatination folder that is an extension of the target folder
if (fchTarget.CurrentFolder.StartsWith(fchDestination.CurrentFolder) || fchDestination.CurrentFolder.StartsWith(fchTarget.CurrentFolder)) {
//creates message box
MessageDialog msdContains = new MessageDialog(this, DialogFlags.Modal, MessageType.Error, ButtonsType.Close, "You cannot sync a folder with one of its parent folders");
//sets message box title
msdContains.Title="Error";
//sets respone type and runs message box
ResponseType response = (ResponseType) msdContains.Run();
//if user clicks on close button or closes window then close message box
if (response == ResponseType.Close || response == ResponseType.DeleteEvent) {
msdContains.Destroy();
}
return;
}
//gets folder size of target folder
FileSizeOfTarget(fchTarget.CurrentFolder);
//gets folder size of destination folder
FileSizeOfDestination(fchDestination.CurrentFolder);
//runs SyncTarget procedure
SyncTarget(fchTarget.CurrentFolder);
//runs SyncDestination procedure
SyncDestination(fchDestination.CurrentFolder);
//informs user process is complete
prgProgressBar.Text = "Finished";
//sets running bool to false
booRunning = false;
}
Sync sub-procedure:
protected void SyncTarget (string strCurrentDirectory)
{
//string array of all the directories in directory
string[] staAllDirectories = Directory.GetDirectories(strCurrentDirectory);
//string array of all the files in directory
string[] staAllFiles = Directory.GetFiles(strCurrentDirectory);
//loop over each file in directory
foreach (string strFile in staAllFiles)
{
//string of just the file's name and not its path
string strFileName = System.IO.Path.GetFileName(strFile);
//string containing directory in target folder
string strDirectoryInsideTarget = System.IO.Path.GetDirectoryName(strFile).Substring(fchTarget.CurrentFolder.Length);
//inform user as to what file is being copied
prgProgressBar.Text="Syncing " + strFile;
//tests if file does not exist in destination folder
if (!File.Exists(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName)) {
//if file does not exist copy it to destination folder, the true below means overwrite if file already exists
File.Copy (strFile, fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName, true);
}
//tests if file does exist in destination folder
if (File.Exists(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName)) {
//long (number) that contains date of last write time of target file
long lngTargetFileDate = File.GetLastWriteTime(strFile).ToFileTime();
//long (number) that contains date of last write time of destination file
long lngDestinationFileDate = File.GetLastWriteTime(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName).ToFileTime();
//tests if target file is newer than destination file
if (lngTargetFileDate > lngDestinationFileDate) {
//if it is newer then copy file from target folder to destination folder
File.Copy (strFile, fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName, true);
}
}
//gets current file size
FileInfo FileSize = new FileInfo(strFile);
//sets file's filesize to dblCurrentStatus and adds it to current total of files
dblCurrentStatus = dblCurrentStatus + FileSize.Length;
double dblPercentage = dblCurrentStatus/dblFolderSize;
prgProgressBar.Fraction = dblPercentage;
}
//loop over each folder in target folder
foreach (string strDirectory in staAllDirectories)
{
//string containing directories inside target folder but not any higher directories
string strDirectoryInsideTarget = strDirectory.Substring(fchTarget.CurrentFolder.Length);
//tests if directory does not exist inside destination folder
if (!Directory.Exists(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget)) {
//it directory does not exisit create it
Directory.CreateDirectory(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget);
}
//run sync on all files in directory
SyncTarget(strDirectory);
}
}
Any help will be greatly appreciated as after this the program will pretty much be finished :D
