How to programmatically create and populate an XmlDataSource with info from filesystem?

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  • Start date Start date
G

Guest

Hi all,

I want to create a method that does the following:
1) Programmatically instantiate a new XmlDataSource control
2) For each file in a named directory, make a "FileSystemItem" element
3) On each FileSystemItem Element, make two child nodes, one with the file
name, one with the file size. ie.

<filesystemitems>
<filesystemitem>
<filename> file1.jpg</filename>
<filesize>48935835</filesize>
</filesystemitem>
<filesystemitem>

I'll bind the resultant XmlDataSource to various controls.

Can someone suggest generally the syntax I want? I know how to loop over
directory items via foreach, but a quick look over MSDN did not suggest how
to instantiate the XmlDataSource control or any kind of .Add method I could
use to populate it.

Thanks!
-KF
 
Hi all,

I want to create a method that does the following:
1) Programmatically instantiate a new XmlDataSource control
2) For each file in a named directory, make a "FileSystemItem" element
3) On each FileSystemItem Element, make two child nodes, one with the file
name, one with the file size. ie.

<filesystemitems>
<filesystemitem>
<filename> file1.jpg</filename>
<filesize>48935835</filesize>
</filesystemitem>
<filesystemitem>

I'll bind the resultant XmlDataSource to various controls.

Can someone suggest generally the syntax I want? I know how to loop over
directory items via foreach, but a quick look over MSDN did not suggest how
to instantiate the XmlDataSource control or any kind of .Add method I could
use to populate it.

Thanks!
-KF
Click to expand...

something like this

Dim dir As New IO.DirectoryInfo(Server.MapPath("/"))
Dim fis As IO.FileInfo() = dir.GetFiles()
Dim fi As IO.FileInfo

Dim s As New IO.MemoryStream()

Dim xw As New System.Xml.XmlTextWriter(s, Encoding.UTF8)
With xw
..WriteStartDocument()
..WriteStartElement("filesystemitems")

For Each fi In fis
..WriteStartElement("filesystemitem", Nothing)
..WriteStartElement("filename", Nothing)
..WriteString(fi.Name)
..WriteEndElement()
..WriteStartElement("filesize", Nothing)
..WriteString(fi.Length)
..WriteEndElement()
..WriteEndElement()
Next fi

..WriteEndElement()
End With
xw.Flush()
 
Thank you, Alexey. Your code taught me a lot. For anyone who's interested, I
converted this to C#. See below

However, I am new to the MemoryStream, and am having trouble converting my
MemoryStream object to a byte array and then to a string, which I want to
response.write to the screen. Could someone please look at my code below and
fill in what needs to happen in my commented area?

Thanks again,
-KF

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Xml;
using System.Text;


public partial class Photo_FilesystemToXmlDataSource : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

DirectoryInfo dir = new DirectoryInfo(@"c:\MyPhysicalPath");
FileInfo[] fis = dir.GetFiles();
//FileInfo fi = new FileInfo();

MemoryStream s = new MemoryStream();
XmlTextWriter xw = new XmlTextWriter(s,Encoding.UTF8);
xw.WriteStartDocument();
xw.WriteStartElement("filesystemitems");

foreach (FileInfo fi in fis)
{
xw.WriteStartElement("filesystemitem");
xw.WriteStartElement("filename");
xw.WriteString(fi.Name);
xw.WriteEndElement();
xw.WriteStartElement("filesizeA");
xw.WriteString(Convert.ToString(fi.Length));
xw.WriteEndElement();
xw.WriteEndElement();
}
xw.WriteEndElement();
xw.Flush();

//???? How do I convert my MemoryStream object to a string and
response.write it here?
// It involves Writing the MemoryStream to a byte array, and
converting it to a string, but I can't get things working quite right
}
}
 
I figured out how to write the file to the filesystem by first casting it to
a byte array and saving it using a FileStream object. I then convert my
byte array to a string using System.Text.Encoding.UTF8 and response.write
it. I read that casting to a byte array is not the most efficient way to do
this. How could I improve this code to be more performant? :

// Write memorystream to a file. This is not the most efficient way
to do this. What's better?
FileStream fs = File.OpenWrite("c:\\blahblah.txt");
byte[] data = s.ToArray();
fs.Write(data, 0, data.Length);
fs.Close();

// Convert the data array to a string and response.write it
string myString = System.Text.Encoding.UTF8.GetString(data);
Response.Write(myString);

Thanks -
-KF

Thank you, Alexey. Your code taught me a lot. For anyone who's interested,
I converted this to C#. See below

However, I am new to the MemoryStream, and am having trouble converting my
MemoryStream object to a byte array and then to a string, which I want to
response.write to the screen. Could someone please look at my code below
and fill in what needs to happen in my commented area?

Thanks again,
-KF

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Xml;
using System.Text;


public partial class Photo_FilesystemToXmlDataSource : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

DirectoryInfo dir = new DirectoryInfo(@"c:\MyPhysicalPath");
FileInfo[] fis = dir.GetFiles();
//FileInfo fi = new FileInfo();

MemoryStream s = new MemoryStream();
XmlTextWriter xw = new XmlTextWriter(s,Encoding.UTF8);
xw.WriteStartDocument();
xw.WriteStartElement("filesystemitems");

foreach (FileInfo fi in fis)
{
xw.WriteStartElement("filesystemitem");
xw.WriteStartElement("filename");
xw.WriteString(fi.Name);
xw.WriteEndElement();
xw.WriteStartElement("filesizeA");
xw.WriteString(Convert.ToString(fi.Length));
xw.WriteEndElement();
xw.WriteEndElement();
}
xw.WriteEndElement();
xw.Flush();

//???? How do I convert my MemoryStream object to a string and
response.write it here?
// It involves Writing the MemoryStream to a byte array, and
converting it to a string, but I can't get things working quite right
}
}


Alexey Smirnov said:
something like this

Dim dir As New IO.DirectoryInfo(Server.MapPath("/"))
Dim fis As IO.FileInfo() = dir.GetFiles()
Dim fi As IO.FileInfo

Dim s As New IO.MemoryStream()

Dim xw As New System.Xml.XmlTextWriter(s, Encoding.UTF8)
With xw
.WriteStartDocument()
.WriteStartElement("filesystemitems")

For Each fi In fis
.WriteStartElement("filesystemitem", Nothing)
.WriteStartElement("filename", Nothing)
.WriteString(fi.Name)
.WriteEndElement()
.WriteStartElement("filesize", Nothing)
.WriteString(fi.Length)
.WriteEndElement()
.WriteEndElement()
Next fi

.WriteEndElement()
End With
xw.Flush()
Click to expand...
Click to expand...
 
I figured out how to write the file to the filesystem by first casting it to
a byte array and saving it using a FileStream object. I then convert my
byte array to a string using System.Text.Encoding.UTF8 and response.write
it. I read that casting to a byte array is not the most efficient way to do
this. How could I improve this code to be more performant? :
Click to expand...

I think you can use a IO.StreamReader()

xw.Flush();
//???? How do I convert my MemoryStream object to a string and
response.write it here?

s.Position = 0;
StreamReader sr = new StreamReader(s);
Response.Write(sr.ReadToEnd());

Hope it helps
 
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