Problem Trying to Rewrite a File Png Images

Marino Liranzo 81

Hello forum friend,

I have this little problem that although there are many questions on the subject, none of them fit my particular problem. The problem is the following.

I have a graph made with wpfPlot.plot.SaveFig(), this graph is generated in a first process and the file is created correctly, in another process the graph must be overwritten with different data; then an error message 'A generic error occurred in GDI+.'

Viorel 114.7K Reputation points

2023-11-12T06:57:29.8833333+00:00

Did you check if you can open (using any editor) and delete the generated file? Maybe it cannot be fully used until your first process is closed, due to some limitations.

If the problem occurs even after terminating the first process, maybe there is an issue in the second program.
Hui Liu-MSFT 47,341 Reputation points Microsoft Vendor

2023-11-20T03:49:24.3733333+00:00

Hi,@Marino Liranzo. Welcome to Microsoft Q&A Forum.

The error message "A generic error occurred in GDI+" in the context of WPF (Windows Presentation Foundation) typically indicates an issue with graphics resources or file handling.

In your case, where you're trying to overwrite a file generated in one process with different data in another process, there might be contention for access to the file or other resource-related issues.

Here are some suggestions you can try to troubleshoot and resolve the issue:

Ensure Proper File Handling:

Make sure that the first process has closed the file properly after saving the graph. This is important to release any file locks and allow other processes to access the file.

In the second process, confirm that you are not trying to overwrite the file while it is still open in the first process.

Concurrency Issues:

If both processes are trying to access the file simultaneously, you might encounter issues. Consider implementing a mechanism to synchronize access to the file, such as using file locks or other synchronization primitives.

Check File Permissions:

Ensure that the second process has the necessary permissions to overwrite the file. File permissions might prevent the second process from modifying the file created by the first process.

Graphics Resource Cleanup:

Make sure that any graphics resources (like brushes, pens, or bitmaps) used in the WPF plot are properly disposed of after use. Failure to dispose of graphics resources can lead to GDI+ errors.

Use Different File Names:

Instead of trying to overwrite the same file, try saving the second graph with a different file name. This can help you identify whether the issue is related to overwriting or if it's a general problem with file access.

2 answers

KOZ6.0 6,300 Reputation points

2023-11-11T02:48:17.89+00:00
Image files may be locked depending on how they are displayed. In this example, the CacheOption property of BitmapImage is set to BitmapCacheOption.OnLoad. This caches the image in memory when it's loaded, preventing the original file from being locked.

BitmapImage bitmap = new BitmapImage(); bitmap.BeginInit(); bitmap.UriSource = new Uri(imagePath, UriKind.RelativeOrAbsolute); bitmap.CacheOption = BitmapCacheOption.OnLoad; bitmap.EndInit(); imageControl.Source = bitmap;
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Marino Liranzo 81 Reputation points

2023-11-11T13:52:03.6666667+00:00

Thank you, considering that the image is displayed in a WpfPlot control, who is imageControl and how do I use the code snippet you provide?

KOZ6.0 6,300 Reputation points

2023-11-11T19:23:38.74+00:00

Sorry, I misread the question.Please forget my answer,
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Marino Liranzo 81 Reputation points

2023-11-12T14:28:35.9766667+00:00

I have tried using the 'File.Delete(path)' method before using wpfPlot.SaveFig(path); however, the file is not deleted.
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Problem Trying to Rewrite a File Png Images

2 answers