I have been fiddling with this problem for the past hour so I thought you guys may be able to help on a Friday afternoon!
Problem
I am trying to edit an XML file in localstorage but can't figure out how to edit the existing file and re-save the file. The edit I have made it to remove a certain node from the XML.
Code
Here is the method that does all the work.
This first code snippet was already in the code and basically creates the XML file and saves it to localstorage.:
protected byte[] CreateFileData(PortableBusinessObjects.Location location, string geoObjectFilename)
{
byte[] fileData = null;
var xmlFile = System.IO.Path.GetFileNameWithoutExtension(geoObjectFilename) + ".xml";
var zipFile = System.IO.Path.GetFileNameWithoutExtension(geoObjectFilename) + ".zip";
using (IsolatedStorageFileStream fileStream = localStorage.CreateFile(xmlFile))
{
XmlWriter writer = XmlWriter.Create(fileStream);
if (location.GetType() == typeof(PortableBusinessObjects.Shape))
_xmlShapeSerializer.Serialize(writer, location);
else if (location.GetType() == typeof(PortableBusinessObjects.Point))
_xmlPointSerializer.Serialize(writer, location);
fileStream.Flush();
fileStream.Close();
}
}
This is my attempt at overwriting the saved file (Doesn't work):
using (IsolatedStorageFileStream doc = localStorage.OpenFile(xmlFile, FileMode.Open))
{
System.Xml.Linq.XDocument test = System.Xml.Linq.XDocument.Load(doc);
test.Descendants("Time").Remove();
XmlWriter writer = XmlWriter.Create(doc);
doc.Flush();
doc.Close();
}
Question
Where do I place my code that removes the "Time" nodes and saves the file?
Your saving code doesn't do any saving - you just create an XmlWriter and do nothing with it.
There are various methods built into XDocument than can help you here. While you could pass your XmlWriter to it, you can actually save directly to the stream:
test.Save(doc);
Note you will need to move to the beginning of the stream before writing to it - loading your XML will have read to the end:
doc.Position = 0;
You should use the IsolatedStorageFileStream together with the StreamWriter.
See How to: Read and Write to Files in Isolated Storage
With XDocument you then have to Save() the new contents to the stream.
Related
I'm trying to edit xml file.
but document.Save() method has to use another file name.
Is there any way to use same file? or other method. Thank you!
string path = "test.xml";
using (FileStream xmlFile = File.OpenRead(path))
{
XDocument document = XDocument.Load(xmlFile);
var setupEl = document.Root;
var groupEl = setupEl.Elements().ElementAt(0);
var valueEl = groupEl.Elements().ElementAt(1);
valueEl.Value = "Test2";
document.Save("test-result.xml");
// document.Save("test.xml"); I want to use this line.
}
I receive the error:
The process cannot access the file '[...]\test.xml' because it is being used by another process.
The problem is that you are trying to write to the file while you still have it open. However, you have no need to have it open once you've loaded the XML file. Simply scoping your code more granularly will solve the issue:
string path = "test.xml";
XDocument document;
using (FileStream xmlFile = File.OpenRead(path))
{
document = XDocument.Load(xmlFile);
}
// the rest of your code
I'm using XDocument to update the XML file with Isolated Storage. However, after save the updated XML file, some extra characters are added automatically.
Here is my XML file before update:
<inventories>
<inventory>
<id>I001</id>
<brand>Apple</brand>
<product>iPhone 5S</product>
<price>750</price>
<description>The newest iPhone</description>
<barcode>1234567</barcode>
<quantity>75</quantity>
<inventory>
</inventories>
Then after the file is updated and saved, it becomes:
<inventories>
<inventory>
<id>I001</id>
<brand>Apple</brand>
<product>iPhone 5S</product>
<price>750</price>
<description>The best iPhone</description>
<barcode>1234567</barcode>
<quantity>7</quantity>
<inventory>
</inventories>ies>
I've spent a lot of time trying to find and fix the problem but no solutions were found. The solution in the post xdocument save adding extra characters cannot help me fix my problem.
Here's my C# code:
private void UpdateInventory(string id)
{
using (IsolatedStorageFile isf = IsolatedStorageFile.GetUserStoreForApplication())
{
using (IsolatedStorageFileStream stream = isf.OpenFile("inventories.xml", FileMode.OpenOrCreate, FileAccess.ReadWrite))
{
XDocument doc = XDocument.Load(stream);
var item = from c in doc.Descendants("inventory")
where c.Element("id").Value == id
select c;
foreach (XElement e in item)
{
e.Element("price").SetValue(txtPrice.Text);
e.Element("description").SetValue(txtDescription.Text);
e.Element("quantity").SetValue(txtQuantity.Text);
}
stream.Position = 0;
doc.Save(stream);
stream.Close();
NavigationService.Navigate(new Uri("/MainPage.xaml", UriKind.Relative));
}
}
}
The most reliable way is to re-create it:
XDocument doc; // declare outside of the using scope
using (IsolatedStorageFileStream stream = isf.OpenFile("inventories.xml",
FileMode.Open, FileAccess.Read))
{
doc = XDocument.Load(stream);
}
// change the document here
using (IsolatedStorageFileStream stream = isf.OpenFile("inventories.xml",
FileMode.Create, // the most critical mode-flag
FileAccess.Write))
{
doc.Save(stream);
}
When I had a similar problem in Python, I discovered that I was overwriting the beginning of the file without truncating it afterwards.
Looking at your code, I'd say you might be doing the same:
stream.Position = 0;
doc.Save(stream);
stream.Close();
Try setting the stream length to its post-save location as per this answer:
stream.Position = 0;
doc.Save(stream);
stream.SetLength(stream.Position);
stream.Close();
I've been trying to modify and save an xml dynamically. i've tried to find some answers but i didnt manage to.
i Succeeded to modify and change the xml data, but i encounter a problem with saving.
here is the code:
var resourceStreamInfo = Application.GetResourceStream(uri);
using (var stream = resourceStreamInfo.Stream)
{
doc = XDocument.Load(stream);
var Currencies = doc.Descendants("Currency");
XElement root = Currencies.Where(b => b.Element("ID").Value.IndexOf(CurrencyID, StringComparison.CurrentCultureIgnoreCase) >= 0).First();
root.SetElementValue("Rate", rate);
doc.Save(stream);
}
I understood that my stream is readonly, but what should I do?
From Application.GetResourceStreamI guess your are reading a file from your project bundle. You cannot modify it. You need to save the modified file to isolated storage
In C# am trying to check to see if an XML file is created, if not create the file and then create the xml declaration, a comment and a parent node.
When I try to load it, it gives me this error:
"The process cannot access the file 'C:\FileMoveResults\Applications.xml' because it is being used by another process."
I checked the task manager to ensure it wasn't open and sure enough there were no open applications of it. Any ideas of what's going on?
Here is the code I am using:
//check for the xml file
if (!File.Exists(GlobalVars.strXMLPath))
{
//create the xml file
File.Create(GlobalVars.strXMLPath);
//create the structure
XmlDocument doc = new XmlDocument();
doc.Load(GlobalVars.strXMLPath);
//create the xml declaration
XmlDeclaration xdec = doc.CreateXmlDeclaration("1.0", null, null);
//create the comment
XmlComment xcom = doc.CreateComment("This file contains all the apps, versions, source and destination paths.");
//create the application parent node
XmlNode newApp = doc.CreateElement("applications");
//save
doc.Save(GlobalVars.strXMLPath);
Here is the code I ended up using to fix this issue:
//check for the xml file
if (!File.Exists(GlobalVars.strXMLPath))
{
using (XmlWriter xWriter = XmlWriter.Create(GlobalVars.strXMLPath))
{
xWriter.WriteStartDocument();
xWriter.WriteComment("This file contains all the apps, versions, source and destination paths.");
xWriter.WriteStartElement("application");
xWriter.WriteFullEndElement();
xWriter.WriteEndDocument();
}
File.Create() returns a FileStream that locks the file until it's closed.
You don't need to call File.Create() at all; doc.Save() will create or overwrite the file.
I would suggest something like this:
string filePath = "C:/myFilePath";
XmlDocument doc = new XmlDocument();
if (System.IO.File.Exists(filePath))
{
doc.Load(filePath);
}
else
{
using (XmlWriter xWriter = XmlWriter.Create(filePath))
{
xWriter.WriteStartDocument();
xWriter.WriteStartElement("Element Name");
xWriter.WriteEndElement();
xWriter.WriteEndDocument();
}
//OR
XmlDeclaration xdec = doc.CreateXmlDeclaration("1.0", null, null);
XmlComment xcom = doc.CreateComment("This file contains all the apps, versions, source and destination paths.");
XmlNode newApp = doc.CreateElement("applications");
XmlNode newApp = doc.CreateElement("applications1");
XmlNode newApp = doc.CreateElement("applications2");
doc.Save(filePath); //save a copy
}
The reason your code is currently having problems is because of: File.Create creates the file and opens the stream to the file, and then you never make use of it (never close it) on this line:
//create the xml file
File.Create(GlobalVars.strXMLPath);
if you did something like
//create the xml file
using(Stream fStream = File.Create(GlobalVars.strXMLPath)) { }
Then you would not get that in use exception.
As a side note XmlDocument.Load will not create a file, only work with an already create one
You could create a stream, setting the FileMode to FileMode.Create and then use the stream to save the Xml to the path specified.
using (System.IO.Stream stream = new System.IO.FileStream(GlobalVars.strXMLPath, FileMode.Create))
{
XmlDocument doc = new XmlDocument();
...
doc.Save(stream);
}
I am trying to serialize my Report class info to an XML. At this point I think all of the serialize and deserialize code works, but for the initial write, I'm having trouble performing the serialize, because the XML file doesn't exist yet.
for an empty text file, i can use:
StreamWriter sw = File.CreateText(#"path");
sw.Close();
this is my code block for the serializing. the exception (Directory not found) is getting thrown on the StreamWriter line. I'd like to simply add an if(!File.Exists(xmlPath))...create empty XML. Or maybe there is a more correct way to do this.
public void SerializeToXML(Report newReport)
{
XmlSerializer serializer = new XmlSerializer(typeof(Report));
TextWriter textWriter = new StreamWriter(xmlPath);
serializer.Serialize(textWriter, newReport);
textWriter.Close();
}
The StreamWriter(String) constructor will create the file if it does not already exist:
If the file exists, it is overwritten; otherwise, a new file is created.
However, it will not create any inexistent directories in your path.
DirectoryNotFoundException: The specified path is invalid, such as being on an unmapped drive.
To create any required directories, you can include the following code (at the beginning of your SerializeToXML method):
var dir = Path.GetDirectoryName(xmlPath);
if (!Directory.Exists(dir))
Directory.CreateDirectory(dir);
First to make sure the directory exist you can use:
Directory.CreateDirectory(#"c:\directory\subdirectory");
You don't have to check if directory already exist.
A easy way to convert public classes to XML is to use the following snippet:
public static string ToXml<T>(T obj)
{
using (var ms = new MemoryStream())
using (var sr = new StreamReader(ms))
{
var xmlSer = new XmlSerializer(typeof(T));
xmlSer.Serialize(ms, obj);
ms.Seek(0, SeekOrigin.Begin);
return sr.ReadToEnd();
}
}
Then you could just use the following code to write it to a file:
var xmlString = Util.ToXml(report);
File.WriteAllText(#"path", xmlString);
(this example is without error handling)
Also, in your code you forgot to close/dispose the TextWriter. I would recommend using the using-statement to handle it for you.
CreateText, and the StreamWriter, will create files if they don't exist, but they won't create directories that don't already exist for you. Is your path correct?
Try Checking with a Directory.Exists(Path.GetDirectoryName(xmlPath)).