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

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kenfine@nospam.nospam - 22 Jun 2007 19:36 GMT

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

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Alexey Smirnov - 23 Jun 2007 15:25 GMT

On Jun 22, 8:36 pm, <kenf...@nospam.nospam> wrote:

> Hi all,
>
[quoted text clipped - 20 lines]
> Thanks!
> -KF

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()

Reply to this Message

kenfine@nospam.nospam - 23 Jun 2007 18:45 GMT

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
}
}

> On Jun 22, 8:36 pm, <kenf...@nospam.nospam> wrote:
>> Hi all,
[quoted text clipped - 52 lines]
> End With
> xw.Flush()

Reply to this Message

kenfine@nospam.nospam - 23 Jun 2007 19:02 GMT

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
[quoted text clipped - 112 lines]
>> End With
>> xw.Flush()

Reply to this Message

Alexey Smirnov - 23 Jun 2007 22:29 GMT

On Jun 23, 8:02 pm, <kenf...@nospam.nospam> wrote:

> 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? :

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

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