Sql Filestream - Update A File And Save Changed File Back To Database
Oct 30, 2009
I have implemented the filestream feature of SQL Server 2008 in a VB.Net application. I can insert files, and then retrieve/view them just fine. However, I have huge problems trying to update a file. Eg. The user selects a file from the grid which I execute via process.start. If that file is a .txt file, the user may choose to edit it. In case that happens, I need to save the changed file back to the database. So far I have failed to do that.
What I do, is take the retrieved file, copy it (cause i got some errors about it being used), and then Process.Start it. After that, via .NET filestream, I convert the file to bytes and try to update the record. SQL Profiler and a manual SELECT on the varbinary(max) column tell me that the file is updated properly, but the very next try to retrieve it I get an unchanged file.
After that I also tried to update the file by changing its File-System Version, but the file still wouldn't seem to update. Does Anyone have a code sample of how I can achieve this operation? Like 500 sites on the internet have examples of how to Insert And Retrieve the file, but not a single example on how to update. This is how my second attempt of trying to update the file via the filesystem looks like. The code for inserting/retrieving is very similar and it works properly. [Code]
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Feb 18, 2010
I have a filestream, and I want to save a file from that filestream? Like there are bytes in that file stream, and from those I want a "file.exe" to automatically appear on my desktop.
I'm using a code snippet, and I think this is the important part:
Dim fstr As New FileStream("file.exe", FileMode.OpenOrCreate, FileAccess.Write)
fstr.Write(validArg1, validArg2, validArg3)
fstr.Close()
Do I have to use a for loop? Or is there a function like this:
IO.File.WriteAllBytes(myPath, fstr.AllBytes)
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Feb 2, 2012
I'm using VB 2010 Express with a local Access DB. I am having trouble determing whether there are changes in a DataGridView to save back to the underlying DB.
The DB has been copied to the project directory and its properties (by selecting it in the Solution Explorer) include Copy to Output Directory: Copy Always, so I know that any changes I make when running a build will disappear on the next build. The problem I'm having is within a run / test session, working with the application.
The Access database has the following connection string, with Application scope:
Provider=Microsoft.Jet.OLEDB.4.0;Data Source="|DataDirectory|Component MI.mdb"
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Nov 19, 2010
# TAG NAME = is saved to a file using the code below but when I load that same file back into a RichTextbox Control using additional code below, I get inconsistent results as I try to parse the text. Has anyone else had this problem?'Save the contents of the RichTextBox into the file.richTextBox.SaveFile(saveFile1.FileName, RichTextBoxStreamType.RichText);'Retrieve contents of File into RichTextBox control Dim logData As String
logData = System.IO.File.ReadAllText(path + "\" + filenname);
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Apr 16, 2009
I have found many pages referring to having the date be part of a txt file being created, but not like the way I need. Having said that, this is what I've got.. [code] I read a page on working with txt files and learned what I could from it. It said to use the method in the beginning of my code for creating the file. It works great, but I would like to have a new file name everday, hence the date being integrated. So even if program was running, when midnight hits, a new txt file is created and new entries are written to that file. But I can't even get the date to be put in there. Everytime I try to make this work by using methods I read about in other pages, I get a syntax error, or a warning saying an end of statement is expected. I'm not sure those methods are compatible with what I've already got going.I was actually trying to store these values in a database, and I got real close I think, but I couldn't get any help to fix my problem so I'm trying to write to daily txt files instead. url....
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Jan 12, 2010
I have a open and file save dialog which I use to open and save file. There are also some labels in the application. During the time a file is open or saved, the file open /save dialog becomes blurred by the background labels. Is there any way to prevent this? The attached pic is given as an example to explain the dilemma.
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May 5, 2012
I changed my Username on my computer from i.e. "xxxxxx x xxxxx" to "Dennis"
VB 2008 during a compile gave me the following error: Error reading icon 'C:Usersxxxxxx x xxxxxAppDataRoamingMicrosoftVBExpress9.0VSProjectApplication.ico' -- The system cannot find the path specified.
The file "VSProjectApplication.ico" is in 'C:UsersDennisAppDataRoamingMicrosoftVBExpress9.0'
Somewhere in the VB2008 "configuration" files I believe that I need to manually change the old path to the new path.
I found the old path in the ".suo" file. The ".suo" file is not a text file. How can I edit the .suo file, save it so that it will work?
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Mar 26, 2010
I have following code which is not working and giving Null Reference Exception.
Dim x As New XmlDocument
x.LoadXml("<HostTxnAmt>123C,</HostTxnAmt> ")
x.InnerText = "123"
MessageBox.Show("Done")
I need to simply update text from xml node and save it back into string.
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Aug 25, 2011
I have a csv file. I need to open it, delete whole row on basis of a column value, Update few of the column values and save the file as .dat file. I am using VB.net 2010
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Apr 7, 2011
with MySQL + vb.net 2008 exp to create back up of MySQL database script file through vb.net
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Nov 11, 2010
I have an application running with a access db. I have written some code to copy & zip the db file to another location (selected by the user) for the purpose of backup. (I am using sharpzipwrapper)Whenever I try to run the code for the copying & zipping it gives me an exception saying that the file cannot be zipped as it is use.Do I have to close all open connections in order to backup the .accdb file? If yes then how? else what do i have to do inorder to get 'access' to the file.Do I have to exit the application to close all connections? These connections are written in code for e.g. :
dim
cnStudent as
oledbconnection
[code].....
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Jan 5, 2010
I want to edit values in datagrid in VB.NET and also want to save changed value in database. How can i do it?
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Nov 19, 2010
can anyone teach me how to save data in microsoft access database and retrieving it back from database?[code]so, how do i save it in that and how do i load their data by typing their ic no only..
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May 19, 2012
Here's the catch - for the program I'm making I would like to avoid creating a copy of the file in its totally unencrypted state (I'm using a modified, quick-and-dirty XOR cipher for that. It's secure enough for my purposes and faster than the stronger encryption). Anyhow, what I would like to do is read a block of data, de/encrypt it (in memory) and then write the changed bytes to the same location they previously would have been within the file.
I've found the problem a little outside my programming abilities, so I was wondering if anybody had a pre-made solution, links to appropriate examples, or an all out explanation.
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Jul 27, 2009
I am writing a program to upload file to the web using Socket and FileStream. Here is the code
Private Sub Read(ByVal state As StateObject)
Dim filestream As FileStream = state.fileStream
filestream.BeginRead(state.readBuffer, 0, StateObject.readBufferSize, New
[Code].....
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Feb 2, 2012
private
void bindingNavigatorDeleteItem_Click(object
sender, EventArgs e)
{
[Code]....
code does not make chages to database when i reopen the application the records exists as earlier.
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Jul 31, 2011
VB.NET i have only one colum in back end database that is roll. .. Now i want to update a particular data .. the data types is integer.. i has a data like 12 and i ant to update it 13 how can i do..
[Code]...
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Apr 19, 2009
here's my nut for the day.. i want to save a file to a folder. here is the code i have:
[Code]...
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Jun 22, 2011
I have written some simple codes which are using FileStream to read a big .zip file.My codes ran fine as expected until I tested to create multiple threads to access that particular same .zip file at the same time.
The error that I've got was > The process cannot access the file 'D: est.zip' because it is being used by another process.Is it possible to read 1 particular file by multiple FileStream instances at the same time?
[Code]...
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Jul 14, 2011
I am connecting to a web service that returns a dataset that I use as a datasource for a windows client datagridview.
Once a user has made changes to the datagridview record(s), how do I get those changes back to the connected dataset and back to the remote database.
I wrote the sql update function in the service:
Code Snippet from web service
<WebMethod()> _
Public Sub Update_equipment_repair(ByVal repair_id As Int64, ByVal date_entered As DateTime, ByVal date_sent_in As DateTime, ByVal date_returned As DateTime, ByVal damage_description As String, ByVal vendor_id As Int64, ByVal repair_description As String)
[Code]....
This displays the records perfectly and I figured out how to delete and insert records via web service.
writing updates from the datagridview back to the database.
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Jul 14, 2011
I am writing a small windows client application that accesses data using a web service that returns datasets.When the dataset is returned, a datagridview's datasource is set to the dataset.
My question is, how do I write changes that were made in the datagridview back to the dataset and then back to the remote database.
[Code]...
Now the client snippet that connects to the service and lists the equipment
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Dec 3, 2010
I just need to edit one field on a datarow and save the changes back to the database. My database is SQL Compact 3.5
I tried many methods but change is not saved to database.
Me.taSet.Fill(Me.Dsset.tblQuestions)
Dsset.tblQuestions.Rows(1).BeginEdit()
Dsset.tblQuestions.Rows(1).Item("ExamID") = "EDITED"
Dsset.tblQuestions.Rows(1).AcceptChanges()
taSet.Update(Dsset.tblQuestions)
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Apr 4, 2009
In my project,I used the wizard in VB.NET2008 Express to connect to my database. I have a data connector, adapter, and dataset controls on my form. I have been able to load the information into the dataset, and used the datCustomers.Customers.AddCustomersRow to add a new row to the dataset with information.
I now want to save the updated dataset to the database. I have tried using the adapterCustomers.Update(datCustomers) command to no avail. how to save the dataset to the database?
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May 8, 2010
I am trying to find a way to allow my users to choose the directory to save files into, THe file name is automatically generated as it has a naming convention and i am able to pre program a location to save to but i d like to be able to allow my users to decide themselves which directory they want to save the files to and to have the ability to choose which directory to save to
[Code]...
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Feb 10, 2010
In my application, i am downloading file from DMS system to my server. Once the file gets downloaded, on some environment, the iis keeps lock of the file and when the application tries to redownload the file and put the file on same location, an error is generated that file is being used by another process. Following is the code :
[Code]...
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Dec 10, 2009
I am writing an audit file that is writing the username, time, and the old/changed values of several variables in the application for each user when they use my application. It is using a FileStream and StreamWriter to access the audit file. All audits for each user will be written to the same file. The issue is that when two users are updating this audit file at the same time, the "old value" of each of the variable is mixing up between the users.
Dim fs As FileStream
Dim w As StreamWriter
Public Sub WriteAudit(ByVal filename As String, ByVal username As String, ByVal oldAddress As String, ByVal newAddress As String, ByVal oldCity As String, ByVal newCity As String)
[code]....
This lives in an AuditLogger class, which is referenced via an instance variable (re-allocated each time the function is accessed).
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Aug 25, 2010
I can edit the values in the dgv cells manually, add rows, delete rows all without problem and then update the database.My problem is in one form where I want to allow the user to filter the rows in the grid and then enter a value in a textbox and programmatically update all the cells in one column with that valueI can update the rows, and see the changes in the datagridview. When I try and update the database (using UpdateQuery on the underlying TableAdapter of the datagird) only some of thechanged rows are being updated I though it might be related
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Oct 13, 2010
I am using the select command to find a specific row and if its found update it but when I update back to live database I get a concurrency error. Here is my
[Code]...
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Nov 16, 2011
I've got a question below:load data from a table in database into a datagridview,make change in datagridview,and use update function to update change back to tablebut 13 changes, only 12 being update back to databaseonly the top row on the datagridview not being update??
For Each orow As DataGridViewRow In DataGridView1.Rows
orow.Cells(1).Value = TextBox1.Text
Next
[code]......
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Mar 11, 2010
Dim da2 As OleDb.OleDbDataAdapter
[code]...
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