Flajaxian Custom Folder Save Location - c#

I see a lot of people coming up with some excessive ways to change the folder location on the fly with flajaxian multiple file upload control.
Was just wondering if the more experienced could take a look at the way I've come up with and let me know if there are any major issues I should be concerned about. (Assuming I have the proper error checking in place.)
I planned on initializing the control as seen below. :
<cc1:FileUploader ID="FileUploader1" runat="server" OnFileReceived="fileUploader_FileReceived" RequestAsPostBack="true">
</cc1:FileUploader>
(I RequestAsPostBack="true" as there are some other controls I need to check in my event handler)
I simply change the HttpFileCollection.SaveAs property in the fileUploader_FileReceived event. Since flajaxian does this one file upload at a time, we can expect that there is only 1 file in the collection (or else we could use a loop).
protected void fileUploader_FileReceived(object sender,
com.flajaxian.FileReceivedEventArgs e)
{
HttpFileCollection files = Request.Files;
// Change path to whichever folder I need
String TempFileName = "C:\\NEW\\PATH\\TO\\Folder\\" + files[0].FileName;
// Save the file.
files[0].SaveAs(TempFileName);
}
This implementation seems to work great as long as the folder is existing! I was just wondering if there is anything technically wrong with an implementation like this, again , assuming all error checking was in place.
Thanks!

A better way to do this would be to use an adapter, and over write the folder location in the
OnFileNameDetermining event. This way, we also get all the goodies with the adapter.
<cc1:FileUploader ID="FileUploader1" runat="server"` OnFileReceived="fileUploader_FileReceived" RequestAsPostBack="true">
<Adapters>
<cc1:FileSaverAdapter runat="server" FolderName="Ups" OnFileNameDetermining="fileUploader_FileDetermined" />
</Adapters>
</cc1:FileUploader>
In the file determined event, we can change the folder location programatically
protected void fileUploader_FileDetermined(object sender, com.flajaxian.FileNameDeterminingEventArgs e)
{
e.FileName = "C:\\NewFolder\\" + e.File.FileName;
}
We can use the FileReceived event to check if the folder exists, and if not, create it.
protected void fileUploader_FileReceived(object sender, com.flajaxian.FileReceivedEventArgs e)
{
int fileIndex = e.Index;
if (fileIndex == 0)
{
// We are on our first file, check if the new folder exists, if not, create it
}
}

What you are doing is fine, although, if you are saving files within the web site, consider using the MapPath method to create a physical folder from a virtual path within the web site
MapPath("/Images/User1")
This my mininal APSX implementation
<fjx:FileUploader ID="FileUploader1" runat="server" OnFileReceived="FileUploader2_FileReceived">
</fjx:FileUploader>
No adapters or folder is specified. When the FileRecevied event fires, I save files to a folder based on the Forms Authentication user name (names do not use characters not allowed in folder names).
Also note that the FileReceivedEventArgs has a reference to the (HTTP) file
e.File
The FileUploader control will show all files processed - you can even set the status code (e.g. 550) if there is an error, which is returned to the client.
Note that, the server call to the FileReceived event does not occur inside a nornal page postback, even if you specify
RequestAsPostBack="true"
So, a PagePreRender does not take place.
The only issue is, how do you perform any other processing at the client after the uploads complete (e.g. showing images uploaded).
Work I have in progress to this end is to use the client side event
FileStateChanged
When the last file is processed
if (file.state > Flajaxian.File_Uploading && isLast) {
I use JQuery to click a hidden submit button. The postback looks through session values stored when the files were saved, and renders back the images into a DIV.
However, an immediate submit causes issues with empty session inside the FileReceived event for some reason (I assume because the internal asynchronous call back has not completed). A pause of a few seconds before initiating the postback works OK.

Related

How do I save multiple user settings in runtime in C#

I am trying to make my app stay the way I left it after closing the app. Therefore I want to save set of items from ListView to the settings and I can't figure out how to do that. I've found some solutions but I believe they are outdated as they don't seem to work.
Image shows set of items in ListView which I want to save so they appear there after restarting the app:
Items
This is where I want them to appear:
Settings
And this is part of code that I've tried out so far
private void btn_SaveConfig_Click(object sender, EventArgs e)
{
int i = 0;
Settings.Default["IP"] = tBox_discoverServerFrom.Text;
Settings.Default["DiscoveredServers"] = cBox_discoveredServers.Text;
foreach (var item in lV_groups.Items)
{
var property = new System.Configuration.SettingsProperty("Group"+i);
property.PropertyType = typeof(string);
property.Name = "Group " + i;
Settings.Default.Properties.Add(property);
Settings.Default.Save();
i++;
}
}
I do not think using the Settings API is a great idea if you want to save any significant amount of data.
I would recommend the following
Create a class describing all the data you want to save. To make serialization easier it should have a parameter less constructor and public setters for all properties. This is sometimes called a Data-Transfer-Object (DTO)
Use json to serialize the object to a file. You would normally place the file in a subfolder in the local app data folder: Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData).
Do the reverse when you start the application. If there is a file, use Json to deserialize it and use it however you want.
You may optionally add logic to save the file periodically, this would allow recovery in case of application crashes. You might also want some system to keep more than one file, in case the application or computer crashes in the middle of a save operation, and the file becomes corrupt.

Application setting doesn't work well

I have a checkbox(Name:tarahi_algouritm) and a button(Name:button1) on my form(Name:frm_choose).I want to save the latest changes on my checkbox as user clicked on the button.it means user run the program and check the checkbox and then click on button and then close the program.when he/she Rerun it,checkbox should be checked.or someway he disable the checkbox and click on button and after another run,checkbox should be disabled.
for this, in application setting(table part) put a checkbox (Name:s_tarahi_algouritm)and choose USER in scope part..as I said changes are apply on checkbox and s_tarahi_algouritm is used for save the latest changes on checkbox.I wrote these codes:
private void frm_choose_Load(object sender, EventArgs e)
{
if (Properties.Settings.Default.s_tarahi_algouritm!=null)
tarahi_algouritm= Properties.Settings.Default.s_tarahi_algouritm;
}
private void button1_Click(object sender, EventArgs e)
{
Properties.Settings.Default.s_tarahi_algouritm = tarahi_algouritm;
Properties.Settings.Default.Save();
}
but When I make changes on checkbox and close the debug and Rerun it,changes are not applied.
what should I do?where is wrong?I am partly beginner so explain explicit.
thank you all
The problem is the settings files are written out in two parts: one to the application settings (which you can't save to) and the other to the user settings (which you can save to). You need to save the user settings (it gets written to your c:\users{userid}... directory).
Look at the most up-voted response to Farzin's link. It explains the issue as well.
Here's a more thorough explanation: App.config: User vs Application Scope
Here's an example.
I created a webform app and added a Settings file to it (called TestSettings.settings). I added two values:
When you run this application it creates a file in the application directory named the same as your executable with .config appended that contains (among other things) a element and a element. But this file only contains the initial values. If you change the value under the element and call Save() it will not update this file. It will create a file:
c:\Users{username}\AppData\Local{appname}{random_dir_name}{version}\user.config
My code to demonstrate this was:
Console.WriteLine(TestSettings.Default["UserValue"]);
TestSettings.Default["UserValue"] = "def";
TestSettings.Default.Save();
I tested many things like:
Properties.Settings.Default.Properties.Add(new System.Configuration.SettingsProperty("a"));
Properties.Settings.Default.Properties["a"].DefaultValue = "b";
Properties.Settings.Default.Save();
it has not error but do not save. In this link:
C# Settings.Default.Save() not saving?
Answered you must add Properties.Settings.Default.Reload(); after saving, I did that but not changed. It seems no one knows the answer.(I read many articles).
It looks like a cancer to me! I suggest you to easily save your settings to a xml file.
Below i add an easy xml saving method:
using System.Xml.Linq;
And
XElement settings;
try
{
settings = XElement.Load("settings.xml"); //beside the app .exe file
}
catch (Exception) // it is first time and you have not file yet.
{
settings = new XElement("settings");
settings.Save("settings.xml");
}
If you want to add new element:
settings.Add(new XElement("firstKey", tarahi_algouritm.Checked.ToString()));
settings.Save("settings.xml");
If you want to read or edit element:
XElement settings = XElement.Load("settings.xml");
string firstKey = settings.Element("firstKey").Value; //reading value
settings.Element("firstKey").Value = "New Value"; //Edit
settings.Save("settings.xml"); //Save
Remember that firstKey is only a name and you can use another names instead.

Epicor C# Opening a Folder from a button

I want to open a folder from a record pulled up in a form in Epicor. I have created a button and so far it opens up the root folder but I want it to go to a sub-folder with the record's name as the sub folder that will be created from SQL stored procedure when a new record is created.
Here is what I have so far:
private void epiButtonC1_Click(object sender, System.EventArgs args)
{
// ** Place Event Handling Code Here **
string folder = "\\\\MasterServ\\Shared\\Customer Attachments\\";
Process.Start("IExplore.exe", folder);
}
I know something needs to be added at the end of the location to call the folder using the record but im not sure what.
When trying to get data out of a control in Epicor, generally speaking you want to go to the EpiDataView to get the value and not the control itself. There are multiple layers of abstraction going on in the form that make control handling wonky.
From your example for the comments I would do this. Code untested so hopefully I didn't make a typo.
EpiDataView edvUD104 = ((EpiDataView)(oTrans.EpiDataViews["UD104"]));
if (edvUD104.HasRow)
{
string folder = "\\\\MasterServ\\Shared\\Customer Attachments\\"
+ edvUD104.dataView[edvUD104.Row]["Key1"].ToString();
Process.Start("IExplore.exe", folder);
}
Edited for readability.

Intercept MS Windows 'SendTo' menu calls?

SCENARIO
I manage and organize many files during the day, the SendTo is the most used feature that I use on Windows.
PROBLEM
By default, when the user clicks an item/link of the contextmenu to send the files, the O.S does not show any kind of advise/notifier indicating that the files are copying to the selected destination.
I consider it a very wrong design issue because for big files its OK ...a progressbar will be shown, but if the files are to small it will not show any progressbar/visual indicator so is not possible to ensure that the files are copied (without manual effort) because I'm human and I could click outside the SendTo contextmenu by error.
So, I would like to develop a personal mini-tool that will help me to optimize my time showing me a notifier window wherever on the screen when I send/copy files using the SendTo feature from the contextmenu, and only the SendTo feature.
QUESTION
In just simple words, I want to detect a copy/send operation from SendTo menu to ensure that the click was done properly on the menu item (and not outside the menu), by also providing additional basic info such as the source folder, the destination folder, and the amount of files or the filepaths.
Any ideas to start developing this tool in the right direction?.
I will be grateful for a code example in C# or else VB.Net, preferably this last.
APPROACH
Since I don't know how to start doing this I mean which could be the easiest or the efficient way to intercept those SendTo calls, firstly I thought to hook the CopyFile or CopyFileEx API functions, but they do not provide the information that I need because that function will be called in any kind of copy operation and not only when I use the SendTo Feature, so I'm lost.
I'm not sure if I should investigate more about internal calls, or maybe investigate more about the windows contextmenu itself instead of messing with function hooks and ugly things that I could avoid.
My main idea is to develop a hidden WinForms (or else a windows service) that stays in background waiting for when I use the SendTo feature (when I click on an item of the SendTo menu) and then show any kind of visual indicator on the screen to ensure that I properly clicked that menu-item and maybe inform about the amount of files that I'm moving and where I'm moving them.
RESEARCH
Here is a code example that I think it demostrates how to instantiate the SendTo com object to create your own?, but its written in c++ and I'm not sure if the example is helpful because my intention is not to replace the SendTo menu but I'll keep this useful info here it it serves for something else:
How to add(enable) standard "Send To" context menu option in a namespace extension
The KNOWNFOLDERID constants docs gives some useful info about the SendTo folder, again I'm not sure if this could help maybe for a read/access monitoring approach?, I just keep the info here:
GUID: {8983036C-27C0-404B-8F08-102D10DCFD74}
Default Path: %APPDATA%\Microsoft\Windows\SendTo
Legacy Default Path: %USERPROFILE%\SendTo
In the Shell Extension Handlers docs there is a Copy hook handler which I don't know if it has relation with the SendTo's COM component and if that could help me in some way,
the same ignorance for IContextMenu::InvokeCommand method reference which maybe I could intercept it to identify a SendTo invocation?
By the moment I feel like flying blind.
I recently found this A managed "Send To" menu class but again its a example written in C/C++ (I think is the same source before) which I don't understand at all and again I'm not sure if that could help me because I repeat that replacing SendTo is not what I have in mind (just because I don't know how to properly do it avoiding all possible risks, I prefer to still let Windows logic copy/send the files, I just want to detect the copy operation to retrieve info)
EXPECTED RESULTS AND USAGE
Step 1:
Select a random file and use the SendTo menu (in my language, Spanish, the command name is 'Enviar a')
Step 2:
Let the .net application's logic (working in background) intercept the SendTo operation to retrieve info.
(I only need help with this step)
Step 3:
Display the info somewhere over the screen to ensure that the SendTo operation was performed, to ensure that I properly clicked the SendTo item (My Link).
(That popup is just a simulation, I don't know any way to retrieve all that info)
It's really simple to do once you understand what SendTo really does, and it doesn't involves COM or shell extensions at all. Basically, the send to menu is populated with the content of the SendTo folder of the user profile (C:\Users\\AppData\Roaming\Microsoft\Windows\SendTo by default in Windows 6.x).
When clicked, if the option is a shortcut to a folder it will copy the files there, but if there is a shortcut to a program (or a program executable itself) it will run that program, passing the paths of the selected files as command-line arguments.
From there, it's really trivial to make some program that simply takes paths as arguments, present some kind of notification and then copies the files or do whatever you want with them.
A quick and dirty example could be as follow (in C#, but could be done with anything else really):
private static void Main(string[] args)
{
if(MessageBox.Show("Are you sure you want to copy files?", "Copy files", MessageBoxButtons.YesNo) == DialogResult.No) return;
foreach (string file in args)
File.Copy(file, Path.Combine("c:\\temp", Path.GetFileName(file));
}
This just ask for confirmation for copying a bunch of files. Note that this really doesn't "intercepts" the send to menu, but rather handles it completely, so it's the program responsability to do any meaningful action. A more serious implementation could use the built-in Windows copy dialog and display some screen with progress or anything else, that's up to your needs.
It could also take some more parameters on the command line. When you place a shortcut in the SendTo folder, the destination could add some more parameters that will be passed as the first ones (before the file names). For example the destination of the shortcut can read c:\program files\copyfiles.exe c:\temp to pass the destination folder instead of hardcoding. The called program must then interpret the first parameter as the destination path and subsequent ones as the source files.
I've had to do something like this before. You don't even have to intercept the SendTo() function, you only need to make sure the the file has arrived. How about FileSystemWatcher if it's on the same computer?
You could use a watcher to watch before you send it, then, if the file successfully arrives at it's destination, you can display a successful message, and then kill the watcher.
Code Example
// Create a FileSystemWatcher property.
FileSystemWatcher fsw { get; set; }
// So we can set the FileToWatch within WatchFilesBeforeTransfer().
private string FileToWatch { get; set; }
private void WatchFilesBeforeTransfer(string FileName, string DestinationFolder)
{
fsw = new FileSystemWatcher();
fsw.Path = DestinationFolder;
FileToWatch = FileName;
// Only if you need support for multiple directories. Code example note included.
fsw.InclueSubdirectories = true;
// We'll be searching for the file name and directory.
fsw.NotifyFilter = NotifyFilters.FileName | NotifyFilters.DirectoryName
// If it's simply moving the file to another location on the computer.
fsw.Renamed += new RenamedEventHandler(FileRenamed);
// If it was copied, not moved or renamed.
fsw.Created += new FileSystemEventHandler(FileCreated);
fsw.EnableRaisingEvents = true;
}
// If the file is just renamed. (Move/Rename)
private void FileRenamed(Object source, RenamedEventArgs e)
{
// Do something.
// Note that the full filename is accessed by e.FullPath.
if (e.Name == FileToWatch)
{
DisplaySuccessfulMessage(e.Name);
KillFileWatcher();
}
}
// If creating a new file. (Copied)
private void FileCreated(Object source, FileSystemEventArgs e)
{
// Do something.
// Note that the full filename is accessed by e.FullPath.
if (e.Name == FileToWatch)
{
DisplaySuccessfulMessage(e.Name);
KillFileWatcher();
}
}
private void KillFileWatcher()
{
fsw.Dispose();
}
You can access the desired property information (like in your popup gif) in this way:
Folder name: Path.GetDirectory(e.FullPath); (like "C:\yo\")
Full file name: e.FullPath (like "C:\yo\hey.exe")
File name: e.Name (like "hey.exe")
Non-code execution process:
Before you initiate SendTo(), create an instance of the FileSystemWatcher property, and have it watch for a specific Folder/File name combination, which should show up in the watched folder: WatchFilesBeforeTransfer(FileName, DestinationFolder).
Initiate SendTo().
File received? DisplaySuccessfulSendToMessage(), KillFileWatcher();
???
Profit.
UPDATE:
I just realized that's just for one file. If you want to check for multiple files, you could either create multiple FileWatcher instances (not recommended), or use a List<string> object, like this:
private void SendTo(List<string> FileCollection)
{
// Clear your previous FileList.
FileList.Clear();
foreach (string file in FileCollection)
{
FileList.Add(file);
}
// Rest of the code.
}
List<string> FileList { get; set; }
private void WatchFilesBeforeTransfer(string DestinationFolder)
{
// Same code as before, but delete FileToWatch.
}
private void FileRenamed(Object source, RenamedEventArgs e)
{
foreach (string file in FileList)
{
if (e.Name == file)
{
// Do stuff.
}
}
}
private void FileCreated(Object source, FileSystemEventArgs e)
{
foreach (string file in FileList)
{
if (e.Name == file)
{
// Do stuff.
}
}
}
Hope this helps!
I'm afraid this ain't that easy.
I was playing around with the FileSystemWatcher on this, but with only partly success.
Something that should definitely work are File system drivers but this looks like just too, well, look at it...
In the end it might be the easiest way to write your own shell extension to access the SendTo folder, and use this instead of the SentTo command which would give you full control.
These might be some starters:
Windows shell extensions
Shell Context Menus
Maybe I come a little bit late to answer my own question, which was published on year 2015, but it wasn't until few days ago that I became interested in this matter again, with much more experience and knowledge gained in .NET after these years to start from scratch and try to understand everything that I did not understood in the past.
I just discovered that, as #Ňɏssa Pøngjǣrdenlarp already commented in the comments box, apparently the most viable way to accomplish this would be to implement my own SendTo context menu and use IFileOperationProgressSink interface to report progress, which for this firstly I need to depend on the usage of IFileOperation interface.
The reason to use the IFileOperation interface is because it seems the only way offered in the Windows API to let the developer perform multiple file operations (copy, move, rename, create or delete) all at once within the same progress dialog UI. This is probably the interface used by the system when the user selects multiple files or directories (via the SendTo menu or just CTRL+C and CTRL+V) to move or copy them at once, because it only shows one progress dialog with all the copy operations queued in it...
So clearly IFileOperation and IFileOperationProgressSink interfaces were what I need. But from what I know there is no managed implementation of these interfaces in the .NET framework namespaces (neither in the Microsoft's WindowsAPICodePack library), which seems somewhat inexcusable to me considering that these interfaces exists since the era of Windows VISTA or even earlier, and it is an indisputable improvement being the totally opposite of any built-in members that you can think of to perform copy, move, rename, create or delete operations, like for example System.IO.File.Copy or Microsoft.VisualBasic.FileIO.FileSystem.CopyFile method. All of them only supports a single operation and only on a single progress dialog at once.
So I focused to investigate on that suggested solution, and I ended up finding a good implementation of IFileOperation and IFileOperationProgressSink interfaces in this repository:
https://github.com/misterhaan/au.Shared/tree/master/IO/Files.FileOperation
And this one which is the original implementation that I found on a old Microsoft's article which also comes with a good PDF reading to learn some things:
https://github.com/mlaily/MSDNMagazine2007-.NET-Matters-IFileOperation-in-Windows-Vista
https://learn.microsoft.com/en-us/archive/msdn-magazine/2007/december/net-matters-ifileoperation-in-windows-vista
Actually, for what I've discussed in this thread to do since year 2015, delving into the use of the IFileOperationProgressSink interface to report progress would not be necessary (only if I really want a deep progress information), since it is enough to determine that the copy was started / the call to IFileOperation.PerformOperations function was performed, and if any problems occur during the copy then it will appear in the progress dialog UI.
But of course what is still necessary is to develop a shell-extension of a custom SendTo menu to replace the one built into Windows. Shell-extensions could be developed with SharpShell library.
I develop in VB.NET language. I managed to extend and document their IFileOperation implementation and the wrapper, and updated the enums adding the newer, missing values added for Windows 7 and Windows 8.
If it can be helpful for someone, I'm going to attach the IFIleOperation and the wrapper in Vb.NET all in a new answer (because it exceeds the maximum character limit allowed for a post).
Note that in my implementation of IFileOperation interface and the wrapper class with name FileSystemOperation you will find some return types and missing classes or methods (like HRESULT return type or NativeMethods class), I just can't share all in one place, but these missing things are things that any experienced programmer will know how to resolve (eg. change HRESULT to UInteger type, and go to Pinvoke.net to find any missing method from my NativeMethods class).
UPDATE
It seems that StackOverflow doesn't allow me to add another answer, so I'll upload my implementation on PasteBin instead:
Class FileSystemOperation
https://pastebin.com/nvgLWEXu
Interface IFileOperation
https://pastebin.com/GzammHtu
Interface IFileOperationProgressSink
https://pastebin.com/jf9JjzyH
Class ComObjectDisposer(Of T As Class)
https://pastebin.com/7mPeawWr
Enum TransferSourceFlags
https://pastebin.com/V7wSSEvv
Enum FileOperationFlags
https://pastebin.com/A223w9XY
That's all.

Why is PictureBox.Load locking image on some systems?

(Please see the edit on the bottom of the question, if you do not want to read the whole story.)
Hi,
I am new to stackoverflow. Don’t get me wrong, I use it quite often. But up until now I never actually posted something. This is because I did not have something new/useful to say and my English is not that good. The first thing (might have) changed, the latter did not.
I ran into a problem at a customer's Windows 7 system quite recently. I was shipping a C# .Net 4.0 Windows Forms application via ClickOnce. Basically, it is an application that creates a bitmap file and shows it to the user. If the bitmap exists prior to the creation, the existing file gets deleted first. After that the new file is created and loaded by a PictureBox.
The following thing occurred at the customer’s system: After starting the application the first creation succeeds – the second and all following ones do not. The file cannot be deleted, because some process is blocking it. This process is the application itself.
System.IO.IOException: The process cannot access the file “filename” because it is being used by another process.
Well, of course that is nothing unusual. The thing is I tested the application on several systems. None showed this exception. And until now I am unable to see an code error.
So I looked a little bit closer on the customer’s system: The only difference I could find is, that they changed the users folder so that they are not located on the windows partition, but on a different one (C:\Users --> D:\Users). I searched for an instruction on the internet and did the same thing on one of my test systems. To my surprise I got the same exception when I ran my application on it.
With that I could change my code so that the exception does not occur anymore. But I do not understand why that is. So maybe there is something wrong with my code and the error just reveals itself under that special circumstances. Or maybe the code is okay and the reason lies somewhere else. I just hoped that you might be able to help me.
So here is some code I put together, that shows the same behavior. I used 3 buttons, an OpenFileDialog and a PictureBox on a Form. First thing to do is to choose an image file. By pressing one of the two remaining buttons it gets copied into the main folder of the application. After being copied it is shown by the PictureBox. By the way, it does not seem to matter if it is a ClickOnce-application or a “normal” one.
String m_FileName;
private void btnChooseFile_Click(object sender, EventArgs e) {
if(openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK) { // If file was chosen, set file name for later use and activate buttons.
m_FileName = "Test" + Path.GetExtension(openFileDialog1.FileName);
}
}
private void button1_Click(object sender, EventArgs e) {
// This is not working.
if(this.pictureBox1.Image != null) {
//Image img = this.pictureBox1.Image; // I was not sure, if maybe the pictureBox somehow prevents the disposing of the image, as long as it's assigned to it.
//this.pictureBox1.ImageLocation = null; // So I set them null, both the image and the image location.
//this.pictureBox1.Image = null;
//img.Dispose(); // Then I disposed the image.
this.pictureBox1.Image.Dispose(); // The short version. It is not working either way.
this.pictureBox1.Image = null;
}
(new FileInfo(openFileDialog1.FileName)).CopyTo(m_FileName, true); // But still this is where the Exception occurs.
this.pictureBox1.Load(m_FileName);
}
private void button2_Click(object sender, EventArgs e) {
//This is working.
if(this.pictureBox1.Image != null) {
//Image img = this.pictureBox1.Image;
//this.pictureBox1.Image = null;
//img.Dispose();
this.pictureBox1.Image.Dispose();
this.pictureBox1.Image = null;
}
(new FileInfo(openFileDialog1.FileName)).CopyTo(m_FileName, true);
pictureBox1.Image = Image.FromFile(m_FileName);
}
What happens now is the following: If I start the application and click button1 twice, I will get the exception (on the second click). If I start it and click button2 twice, I will not. If I start the application and click buttons1 first and after that button2, I will get the exception. So, the Picture.Load-Function somehow blocks the file, even if I dispose it.
When I searched on the internet, I found an article from microsoft: http://support.microsoft.com/kb/309482/en-us. But it does not hit the bull's eye.
Take into account, that both versions are working on all my test machines. I just get the exception when I change the users folder to a non-windows-partition.
Why is that? And where is the difference in the presented versions?
Edit
Okay, because of the first and only reaction so far, it seems to me, that it is still not clear, what really happens: If I take the above code, put it in a Windows Forms application, compile it and run it on different computers (at work, at home, does not matter) it works - both button1 and button2 (with the Click-functions linked to them) can be used as often as I like - no exception thrown. If I run the application on a computer, where I changed the users folder, and click button1 the second time - bam - IOException, file locked by process. Button2 works as long as I do not press button1.
The first answer implies, that I should get the locking on every system. But I DO NOT (as long as I do not change the users folder)! I tested it on every single computer I could get my hands on - no IOException. I set up a new system, just to rule out some special changes to the systems in my company - both buttonx_Click functions worked - no exception either. I even compiled the program on another computer - same behavior. The only three systems to throw that exception were the ones with the changed users folder.
So far I have no clue, why this difference in behavior occurs. Can somebody help me?
Anybody?
Yes, this is normal. Happens on any operating system, doesn't have anything to do with the Users folder location. The PictureBox.Load() method was intented to be used to load images from locations other than the file system. Like a web site. Which is slow, it avoids freezing the UI while the download is taking place.
It internally uses a FileStream when it discovers that the url you pass is actually a file and not a website name. This FileStream does not get disposed until the PictureBox itself is disposed or you call the Load() method again. A requirement because Image.FromStream() requires the stream to remain readable until the image is no longer used. It is this FileStream that keeps a lock on the file. Disposing the PictureBox.Image is not enough to also dispose the FileStream, the Image object doesn't know that it is being displayed inside a picture box.
There are several ways to solve this problem:
Use the Image property instead of Load(), assign it from Image.FromFile(). Disposing the Image now also releases the lock on the file. As you found out
Keep a dummy image around, one that perhaps displays a "Loading..." bitmap. Load() it first to release the lock on the file
Dispose the PictureBox and recreate it.
This works and unlocks the file
Image img= Image.FromFile(mypath);
Graphics g = pictureBox1.CreateGraphics();
g.DrawImage(img,0,0);
img.Dispose();

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