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Why a xml file remain being used by a process after loaded with MyDoc.Load method ??

Posted on 2008-06-24
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Last Modified: 2010-04-21
Hi

I have a VB NET application.

In the main form, I am creating an xml file, and after that, I am calling a child form that tries to read it xml file, and proccess it.

The first time that I run it process, all is OK, in other words, the xml file is successfully created, after that, the other form is called, and them, the xml file is successfully acceded.
.
The next times, the xml file is created ok with new data, but when I call the child form, I can not open the xml file, and I receive the following error:

The process cannot access the file 'C:\Documents and Settings\LUIS\Local Settings\MyCompany\Cache\MyFile.xml' because it is being used by another process.

The only way I can release it, is to exit of my application.

What I am doing wrong?

Why the xml file remain being used by a process ?

Please see the attached example.

Thanks in advance

Luis
' This is the sub in the main form

 

Dim MyDoc As New XmlDocument()

Dim NewElement As XmlElement = Nothing

Dim NewAtribute As XmlAttribute = Nothing

 

MyDoc.LoadXml("<XmlData></XmlData>") ' I allway will create the file

 

NewElement = MyDoc.CreateElement("Headers")

 

NewAtribute = MyDoc.CreateAttribute("Value1")

NewAtribute.Value = "1"

NewElement.Attributes.Append(NewAtribute)

 

NewAtribute = MyDoc.CreateAttribute("Value2")

NewAtribute.Value = "2"

NewElement.Attributes.Append(NewAtribute)

 

MyDoc.DocumentElement.AppendChild(NewElement)

 

...

... More rows are inserted as needed

...

 

 

Dim UserPath As String = Path.GetFullPath(Path.Combine (Environment.GetFolderPath   (Environment.SpecialFolder.LocalApplicationData), "..\\MyCompany\Cache"))

 

Dim Writer As XmlTextWriter = New XmlTextWriter(UserPath & "\MyFile.xml", Nothing)

 

Writer.Formatting = Formatting.Indented

 

' This allways write OK, the first time, and the next times....

MyDoc.Save(Writer) 

 

MyDoc = Nothing

 

ChildForm.ShowDialog() ' Here I call the child form

 

 

********************************************************************

 

 

Following the child form:

 

 

Private Sub ChildForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

 

Dim ListNodes_Headers As XmlNodeList = Nothing

Dim Node As XmlNode = Nothing

 

Dim MyDoc As New XmlDocument()

 

Dim UserPath As String = Path.GetFullPath(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "..\\MyCompany\Cache"))

 

' The following, fails after the first time

MyDoc.Load(UserPath & "\MyFile.xml") ' Here I receive the error

 

ListNodes_Headers = MyDoc.SelectNodes("//Headers")

 

For Each Node In ListNodes_Headers

 

    Dim Value1 as string = Node.Attributes("Value1").Value

    Dim Value2 as string = Node.Attributes("Value2").Value

 

Next

 

MyDoc = Nothing
 

End Sub

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Comment
Question by:luiggye
  • 2
4 Comments
 
LVL 62

Accepted Solution

by:
Fernando Soto earned 500 total points
Comment Utility
Hi luiggye;

You need to release the file resources after using it. see sample code.

MyDoc.Save(Writer)
' Close the file
Writer.Close()
MyDoc = Nothing

Fernando
0
 
LVL 14

Expert Comment

by:rachitkohli
Comment Utility
Try using with stream


        Dim fs As IO.FileStream
        fs = New IO.FileStream("FILE_PATH", IO.FileMode.Open, IO.FileAccess.Read)
        MyDoc .Load(fs)
        fs.Close()
0
 

Author Closing Comment

by:luiggye
Comment Utility
Thanks Fernando, It worked...
0
 
LVL 62

Expert Comment

by:Fernando Soto
Comment Utility
Not a problem, glad I was able to help. ;=)
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