Releasing bitmap file after open
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I read a bitmap from file with the following code: Bitmap tempBitmap = new Bitmap(bitmapFileName); Later I want to save an updated version of the bitmap with this code: if (System.IO.File.Exists(bitmapFileName) System.IO.File.Delete(bitmapFileName); tempBitmap.Save(bitmapFileName); Unfortunately, when it gets to the delete, I get the following error: "System.IO.IOException: The process cannot access the file "filename.bmp" because it is being used by another process." The creation of the bitmap from file is holding on to the connection. I tried cloning and copying to the clipboard, but the only way I have been able to get this to work is by copying all my bitmaps to temp files and opening from the temp file. Then the file I delete and save to is a different file. I am hoping there is a better way.
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I read a bitmap from file with the following code: Bitmap tempBitmap = new Bitmap(bitmapFileName); Later I want to save an updated version of the bitmap with this code: if (System.IO.File.Exists(bitmapFileName) System.IO.File.Delete(bitmapFileName); tempBitmap.Save(bitmapFileName); Unfortunately, when it gets to the delete, I get the following error: "System.IO.IOException: The process cannot access the file "filename.bmp" because it is being used by another process." The creation of the bitmap from file is holding on to the connection. I tried cloning and copying to the clipboard, but the only way I have been able to get this to work is by copying all my bitmaps to temp files and opening from the temp file. Then the file I delete and save to is a different file. I am hoping there is a better way.
The Bitmap object holds the file open for the lifetime of the object. The trick is to read the file yourself, create the bitmap from that stream, then close the stream.
FileStream fs = new FileStream(@"C:\bitmap.bmp");
Bitmap b = new Bitmap(fs);
fs.Close();RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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The Bitmap object holds the file open for the lifetime of the object. The trick is to read the file yourself, create the bitmap from that stream, then close the stream.
FileStream fs = new FileStream(@"C:\bitmap.bmp");
Bitmap b = new Bitmap(fs);
fs.Close();RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
From MSDN, You must keep the stream open for the lifetime of the Bitmap object. Live Life King Size Alomgir Miah
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From MSDN, You must keep the stream open for the lifetime of the Bitmap object. Live Life King Size Alomgir Miah
I tried using the Filestream and closing it after creating the bitmap. It is working. Why must the stream remain open?
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I tried using the Filestream and closing it after creating the bitmap. It is working. Why must the stream remain open?
If its working thats fine. But in some situations you might get Generic GDI+ error. Check this http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfSystemDrawingBitmapClassctorTopic6.asp So you should implement IDisposable interface and close the stream when Dispose Method is called. I have written a BitmapHelper, hope this helps, using System; using System.IO; using System.Drawing; namespace Test.Controls { /// /// Summary description for BitmapHelper. /// public class BitmapHelper: IDisposable { private Bitmap _bm; private Icon _ic; private MemoryStream _ms; // Track whether Dispose has been called. private bool disposed = false; public BitmapHelper() { } public void LoadBitmap(Stream sm) { Clear(); int len = (int) sm.Length; byte[] buf = new byte[len]; sm.Read(buf,0,len); _ms = new MemoryStream(buf); _bm = (Bitmap) Image.FromStream(_ms); } public void LoadIcon(Stream sm) { Clear(); int len = (int) sm.Length; byte[] buf = new byte[len]; sm.Read(buf,0,len); _ms = new MemoryStream(buf); _ic = new Icon(_ms); } public void LoadBitmap(string fileName) { FileStream fs = new FileStream(fileName,FileMode.Open,FileAccess.Read); LoadBitmap(fs); fs.Close(); } public void LoadIcon(string fileName) { FileStream fs = new FileStream(fileName,FileMode.Open,FileAccess.Read); LoadIcon(fs); fs.Close(); } public void LoadBitmap(object dbField) { Clear(); if (dbField != DBNull.Value) { byte[] buf = (byte[])dbField; _ms = new MemoryStream(buf); _bm = (Bitmap) Image.FromStream(_ms); } } public void LoadIcon(object dbField) { Clear(); if (dbField != DBNull.Value) { byte[] buf = (byte[])dbField; _ms = new MemoryStream(buf); _ic = new Icon(_ms); } } public void Clear() { if (_bm != null) { _bm.Dispose(); _bm = null; } if (_ic != null) { _ic.Dispose(); _ic = null; } if (_ms != null) { _ms.Close(); _ms = null; } } // Implement IDisposable. // Do not make this method virtual. // A derived class should not be able to
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From MSDN, You must keep the stream open for the lifetime of the Bitmap object. Live Life King Size Alomgir Miah
Never have I had a problem with a Generic GDI error while using a Bitmap object. And I've created Bitmap objects from just about every imaginable source, be it a resource stream, external file, serialized network stream, XML data, SQL database, ... Come to think of it, I've never had a GDI+ error that wasn't caused by me doing something stupid, like trying to draw to the same object from two different threads at the same time. If you have to keep the stream open, why does MSDN have an article that shows you how to get around this -> PRB: Image File Is Locked When You Set the PictureBox Image Property to a File[^] The Bitmap class inherits from Image, so I fail to why you would have to keep the stream open for a Bitmap object and not for an Image object. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Never have I had a problem with a Generic GDI error while using a Bitmap object. And I've created Bitmap objects from just about every imaginable source, be it a resource stream, external file, serialized network stream, XML data, SQL database, ... Come to think of it, I've never had a GDI+ error that wasn't caused by me doing something stupid, like trying to draw to the same object from two different threads at the same time. If you have to keep the stream open, why does MSDN have an article that shows you how to get around this -> PRB: Image File Is Locked When You Set the PictureBox Image Property to a File[^] The Bitmap class inherits from Image, so I fail to why you would have to keep the stream open for a Bitmap object and not for an Image object. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
Closing the stream is working for me. Thanks
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Closing the stream is working for me. Thanks
Straight from MSDN Remarks You must keep the stream open for the lifetime of the Bitmap object. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfSystemDrawingBitmapClassctorTopic6.asp This happens sometimes when the OnPaint tries to access the BitMap and gets a null. Live Life King Size Alomgir Miah
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Straight from MSDN Remarks You must keep the stream open for the lifetime of the Bitmap object. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfSystemDrawingBitmapClassctorTopic6.asp This happens sometimes when the OnPaint tries to access the BitMap and gets a null. Live Life King Size Alomgir Miah
So it is... But, like I said, never had a problem with it. I fail to see why any Bitmap object (properly defined) would ever come back as null in the middle of OnPaint. I've never had it happen in any painting of any of my forms or controls. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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So it is... But, like I said, never had a problem with it. I fail to see why any Bitmap object (properly defined) would ever come back as null in the middle of OnPaint. I've never had it happen in any painting of any of my forms or controls. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
Try adding a toolbar to your application. In each toolbar add a button. Set an ImageList with BitMap streams. If you close the stream see what happens. Live Life King Size Alomgir Miah
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Try adding a toolbar to your application. In each toolbar add a button. Set an ImageList with BitMap streams. If you close the stream see what happens. Live Life King Size Alomgir Miah
How many times do I have to tell you, I've never had a problem with it! I know about that little quirk! That's why I NEVER keep my Toolbar images in files. I keep them in Resources! I hate having open files laying around. I keep as many images as I can in resources. I've even developed an ImageResources resource .DLL that holds my common images, including Toolbar buttons, in various sizes, masks, and transparencies. It's completely static so I don't have to instantiate the thing either. Instead of deploying a bunch of image files along with my apps, I only deploy a sinlge .DLL. Now, all I have to do to set a Toolbar button image is:
SaveButton.Image = ImageResources.Buttons.Retrieve("Save 16x16 Trans.bmp")
Obviously,
Retrieve()returns a Bitmap object. And "Look Ma!," no open file handles! RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome -
How many times do I have to tell you, I've never had a problem with it! I know about that little quirk! That's why I NEVER keep my Toolbar images in files. I keep them in Resources! I hate having open files laying around. I keep as many images as I can in resources. I've even developed an ImageResources resource .DLL that holds my common images, including Toolbar buttons, in various sizes, masks, and transparencies. It's completely static so I don't have to instantiate the thing either. Instead of deploying a bunch of image files along with my apps, I only deploy a sinlge .DLL. Now, all I have to do to set a Toolbar button image is:
SaveButton.Image = ImageResources.Buttons.Retrieve("Save 16x16 Trans.bmp")
Obviously,
Retrieve()returns a Bitmap object. And "Look Ma!," no open file handles! RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming GnomeCalm down man. There is one more way, compile the images as embedded resources into a DLL, this way you have just one DLL. Still you have to open an stream. FYI, when you use resource files to embed images, a stream is opened internally. If you dont trust debug for yourself. SO I am not fighting here, I am just trying to make my point. Live Life King Size Alomgir Miah
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Calm down man. There is one more way, compile the images as embedded resources into a DLL, this way you have just one DLL. Still you have to open an stream. FYI, when you use resource files to embed images, a stream is opened internally. If you dont trust debug for yourself. SO I am not fighting here, I am just trying to make my point. Live Life King Size Alomgir Miah
Alomgir Miah wrote: when you use resource files to embed images, a stream is opened internally. Ya! Why do you think I said "no open file handles"? You just made it sound like there was only one way to create images, using FromFile, and that EVERY Bitmap had to have an open stream associated with it. That's just not true. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Alomgir Miah wrote: when you use resource files to embed images, a stream is opened internally. Ya! Why do you think I said "no open file handles"? You just made it sound like there was only one way to create images, using FromFile, and that EVERY Bitmap had to have an open stream associated with it. That's just not true. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
lol u r tough. lets wrap it up. Live Life King Size Alomgir Miah