Using (Database db = new Database(false, true))Īlso, the second argument "noDocument" for the Database constructor should be "true" and you'd better use FileShare.Read instead of FileShare.ReadWrite: you do not want to hold the file for writinig just to retrieve preview image, unless you do want to change the content of the database.
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FILESHARE READWRITE CODE
For example, if a drawiing is opened in a side database and then being saved by Database.SaveAs(), there will be no ThumbnailBitmap generated, exsiting thumbnail previously saved will also be lost.Īnd yes, your code should be able to retrieve the Thumbnailbitmap, if the drawing's prevuous saving process did generate one.Ī side note: in your code, you'd better make sure the side database is disposed by: The name field in the fileShares section of the results from the instances describe command. Write, FileShare.ReadWrite) The below commands show the error I get when trying to open it in powershell. Syntax: public static System.IO.FileStream Open (string path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO. Dropbox serves over 200 million users and 4 million businesses. I was thinking about trying to read/write to the file and if it returns an IOException, I try again a while later. Content-Range: bytes 22234-62887922/62887923. The ubiquitous Dropbox tops the list of file sharing services in terms of popularity and users. FileStream fs new FileStream('C:\file.dat', FileMode.Open, FileAccess.Read, FileShare.ReadWrite) I'd like to know if anybody had this problem before. Now lets look at the response of this request. Otherwise if a value is provided then itll read that portion only. The FILESHARENAME field in the results from the instances list command. File.Open (String, FileMode, FileAccess, FileShare) is an inbuilt File class method that is used to open a FileStream on the specified path, having the specified mode with read, write, or read/write access and the specified sharing option. If nothing is specified in the To part then itll read the file to the end and write it in the response.
![fileshare readwrite fileshare readwrite](https://i.stack.imgur.com/CRamr.png)
The fact is, a drawing file (drawing database) may not always have a ThumbnailBitmap stored in it (that is why you get "null" from the property), depending on how the drawing file was saved previously. You can get the file share name of an instance from any of following sources: The Filestore instances page in the Google Cloud console.
![fileshare readwrite fileshare readwrite](http://country-programmer.dfkp.info/wp-content/uploads/2021/04/cs_closedxml_cell_merge_001_001-710x367.png)
Is there any particular reason for opening the file with FileShare.None? That'll prevent the file from being opened by any other process.įileShare.Write or FileShare.ReadWrite should allow the other process (subject to permissions) to open and write to the file while you are reading it, however you'll have to watch for the file changing underneath you while you read it - simply buffering the contents upon opening may help here.Īll of these answers, however, are equally valid - the best solution depends on exactly what you're trying to do with the file: if it's important to read it while guaranteeing it doesn't change, then lock it and handle the subsequent exception in your writing code if it's important to read and write to it at the same time, then change the FileShare constant.Yes, Database.ThumbnailBitmap is an implemented property of Database, at least for the alst a few AutoCAD release (4/13/12.I am not sure how old it can go back). The timer event do works but as in my very first post I mentioned that Server.MapPath didn´t work in the Global. Here is a VB example of a Mutex like this that I found, it should be easy enough to convert to C#. 221return new FileStream(path, FileMode.Create, FileAccess.ReadWrite, FileShare.None, bufferSize) 227return new FileStream(path, FileMode.Create, FileAccess. So in the notification process that is currently working with the FileSystemWatcher, simply check to see if you need to wait for the mutex, if you do, it will wait, then process. If a file is opened within your application and the FileShare parameter of the FileStream.Open call is set to FileShare.ReadWrite or FileShare.Write, other code in your application can view or alter the contents of the file while you are using it. If you create a named Mutex you can define the mutex in the writing application, and have the reading application wait until the mutex is released. If you want to ensure that readers will always read an up-to-date file, you will either need to use a locking file that indicates someone is writing to the file (though you may get a race condition if not carefully implemented) or make sure you block write-sharing when opening to read and handle the exception so you can try again until you get exclusive access. using (FileStream stream = new FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) Other file access just opens the file for reading and not writing, and allows readwrite sharing. Declaration of template arithmetic operators for values of the FileShare enum type. You can open a file for writing and only lock write access, thereby allowing others to still read the file.įor example, using (FileStream stream = new FileMode.Open, FileAccess.ReadWrite, FileShare.Read))