CPBar for latest article briefs (RSS feed)






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Jul 7, 2003
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This article is about creating a vertical explorer bar which displays CodeProject's latest article briefs from its RSS feed.
- Download CPBar project (source include) - 128 kb
- Download CPBarSetup (executable only) - 57 kb
- Download CPBarSetup project (source included) - 64 kb
Introduction
I have implement this explorer bar with the help of the BandObject
base class as well as this article Extending
Explorer with Band Objects using .NET and Windows Forms. This vertical
explorer bar actually consumes the RSS feed for CodeProject's latest article
briefs at http://www.codeproject.com/webservices/articlerss.aspx,
extract the details of each article and then display them in a scrolling
fashion.
An overview of CPBar design
The CodeProjectBar
object is something like a form which you can just drag
and drop controls from the toolbox. As for ScrollScreen
, it is a custom control
that holds many RichLabel
objects and coordinate their scrolling through the use
of a timer. The RichLabel
object does nothing more than just organizing and
formatting the data for display. Besides that, it is also supposed to hide the
caret. (See Issues yet to address section)
Consuming CP's RSS Feed
The diagram above shows part of what is contained in the RSS feed file. Each item tag represent an article brief and between them contains information such as article title, description, author, etc. So to extract them, here is what I have done.
private void DownloadCPRSSFeed(string url /* url of the rss feed */)
{
XmlTextReader xmlTextReader = new XmlTextReader(url);
// We don't want to handle whitespaces
xmlTextReader.WhitespaceHandling = WhitespaceHandling.None;
// Read through the xml document
while(xmlTextReader.Read())
{
// Check if this is an element of name "item", continue reading
if (xmlTextReader.NodeType == XmlNodeType.Element
&& xmlTextReader.Name == "item")
{
// Continue read
xmlTextReader.Read();
// Get the content for each element. Although I am
// not interested in the "category"
// data, i still need to follow the order so that
// I can reach the date section.
string title = xmlTextReader.ReadElementString("title");
string desc = xmlTextReader.ReadElementString("description");
string link = xmlTextReader.ReadElementString("link");
string author = xmlTextReader.ReadElementString("author");
string category = xmlTextReader.ReadElementString("category");
string date = xmlTextReader.ReadElementString("pubDate");
// Add an item for these data to our scroll screen
scrollArticlesScreen.AddItem(date, title, link, author, desc);
}
}
}
Setting up the CPBar
This is a simple setup program to install the CPBar onto your machine. Below shows the code for the installation and uninstallation part.
// Install
private void btnInstallCPBar_Click(object sender, System.EventArgs e)
{
// Run "gacutil.exe /i CPBar.dll" and "regasm CPBar.dll"
System.Diagnostics.Process.Start(Application.StartupPath +
'\\' + "gacutil.exe", "/i CPBar.dll");
System.Diagnostics.Process.Start(Application.StartupPath +
'\\' + "regasm.exe", "CPBar.dll");
}
// Uninstall
private void btnUninstallCPBar_Click(object sender, System.EventArgs e)
{
// Run "regasm /u CPBar.dll" and "gacutil.exe /u CPBar.dll"
System.Diagnostics.Process.Start(Application.StartupPath + '\\'
+ "regasm.exe", "/u CPBar.dll");
System.Diagnostics.Process.Start(Application.StartupPath + '\\'
+ "gacutil.exe", "/u CPBar.dll");
}
Issues yet to address
Here are some issues that i have encountered but until now, I still couldn't find solution for them.
- Hand cursor not shown when it is over link in
RichLabel
(but the link still works)
This is actually not the case when the ScrollScreen
is not hosted in
CodeProjectBar
. i.e. I created another application and drag my ScrollScreen
control onto it.
- Caret is still visible when
RichLabel
is being clicked
I couldn't find any method like HideCaret()
or something like that in C#.
History
None.