Download RSSRead.zip - 7.79 KB
This is what we are going to develop. Looks pretty cool ... isn't it:
The input to our webpart will be multiple RSS url (maximum 4) and corresponding image
Url(optional) which be displayed next to RSS feeds.
Each RSS feed will be displayed in a separate tab and each item as a collapsible item with
description. The collapsibility is almost same as out of the box webpart except that we will make use of + and – sign to indicate collapsibility using client script.
We will Also have the custom properties for Update Interval – The interval after which the
webpart will update itself without postback.
Now its time to start coding the webpart. To separate the presentation from implementation, we will implement the RSS Reader in a different class than the webpart.
This class contains a static method GetFeeds which accepts a RSS URL(sharepoint only) and
returns a DataTable containing 4 columns with rows=number of items+2. The last two rows
contain the timestamp, title of the list and URL to the list.
Here is the code for the same, I have tried to make it as simple as possible:
class RSSRead
{
internal static System.Data.DataSet GetFeeds(string url)
{
System.Data.DataSet ds = new System.Data.DataSet();
System.Data.DataTable dtFeeds = new System.Data.DataTable();
dtFeeds.Columns.Add("Title");
dtFeeds.Columns.Add("Url");
dtFeeds.Columns.Add("PublishDate");
dtFeeds.Columns.Add("Content");
System.Data.DataTable info = new System.Data.DataTable();
info.Columns.Add("Title");
XmlDocument doc = null;
try
{
doc = new XmlDocument();
WebClient wc = new WebClient();
wc.UseDefaultCredentials = true;
string xml = wc.DownloadString(url);
xml = xml.Substring(3);
doc.LoadXml(xml);
}
XmlNode nRoot = doc.DocumentElement;
XmlNodeList nNodes = nRoot.SelectNodes("channel/item");
System.Data.DataRow dr2 = info.NewRow();
dr2["Title"] =
nRoot.SelectSingleNode("channel/title").InnerText; ;
info.Rows.Add(dr2);
dr2 = info.NewRow();
dr2["Title"] =
nRoot.SelectSingleNode("channel/link").InnerText;
info.Rows.Add(dr2);
foreach (XmlNode node in nNodes)
{
System.Data.DataRow dr = dtFeeds.NewRow();
dr["Title"] = node.SelectSingleNode("title").InnerText;
dr["Url"] = node.SelectSingleNode("link").InnerText;
dr["PublishDate"] =
node.SelectSingleNode("pubDate").InnerText;
dr["PublishDate"] =
Convert.ToDateTime(dr["PublishDate"].ToString()).ToUniversalTime().ToString
();
dr["Content"] =
node.SelectSingleNode("description").InnerText;
dtFeeds.Rows.Add(dr);
}
}
catch (Exception ee)
{
System.Data.DataRow dr2 = info.NewRow();
dr2["Title"] = ee.Message;
info.Rows.Add(dr2);
ds.Tables.Add(info);
return ds;
}
System.Data.DataRow dr1 = info.NewRow();
dr1["Title"] = DateTime.Now.ToLongTimeString();
info.Rows.Add(dr1);
ds.Tables.Add(dtFeeds);
ds.Tables.Add(info);
return ds;
}
} Now to start, we will setup the custom properties for our webpart. I have taken a string arrays of length four to implement eight properties for each tab i.e. RSS Url and image Url. Coming to the structure of our webpart, We would have place one UpdatePanel control. Inside the UpdatePanel, we would have four TabPanel containing one label each for the UpdateProgress Control to display a simple animating image while the data is updating and a Timer Control to refresh the UpdatePanel whenever the time interval elapses.
- UpdatePanel control
- TabContainer control
- TabPanel control(s)
- Label control(s)
private string []_rssurl=new string[4];
private string[] _rssimgurl = new string[4];
TabPanel []tabs=new TabPanel[4];
TabContainer tc;
Label[] rsstext = new Label[4];
UpdatePanel rsspanel;
UpdateProgress rssprogress;
Timer ajaxtimer;
int _updateinterval=120;
int _imgpanelwidth = 0;
[DefaultValue("")]
[WebPartStorage(Storage.Shared)]
[FriendlyNameAttribute("1st RSS Feed URL")]
[Description("Put 1st the RSS Feed URL")]
[Browsable(true)]
[XmlElement(ElementName = "RSSUrl")]
public string RSSUrl
{
get
{
return _rssurl[0];
}
set
{
Uri url=new Uri(value,UriKind.Absolute);
if (url.GetLeftPart(UriPartial.Path).Contains(rssstr))
{
_rssurl[0] = value;
}
}
}
[DefaultValue("")]
[WebPartStorage(Storage.Shared)]
[FriendlyNameAttribute("1st Tab Image URL")]
[Description("Put 1st Tab Imag URL")]
[Browsable(true)]
[XmlElement(ElementName = "RSSimgUrl")]
public string RSSImgUrl
{
get
{
return _rssimgurl[0];
}
set
{
_rssimgurl[0] = value;
}
}
To work with AJAX, we need to declare the ScriptManager object. We will make OnInit() function of webpartScriptManager and initialize the TabContainer and TabPanel.ScriptManager object on the page TabContainer to style our control.protected override void OnInit(EventArgs e)
{
// Let's find if the ScriptManager exists and add it if not
ScriptManager scriptManager = ScriptManager.GetCurrent(Page);
if (scriptManager == null)
{
scriptManager = new ScriptManager();
scriptManager.EnablePartialRendering = true;
scriptManager.ID = "sm";
if (Page.Form != null)
{
// Insert script manager after the web part manager
for (int controlIndex = 0; controlIndex <
Page.Form.Controls.Count; controlIndex++)
{
if (Page.Form.Controls[controlIndex].GetType() ==
WebPartManager.GetType())
{
Page.Form.Controls.AddAt(controlIndex + 1,
scriptManager);
}
}
}
}
tc = new TabContainer();
tc.ID = "tc";
tc.BorderWidth = Unit.Pixel(0);
for (int i = 0; i < 4; ++i)
{
tabs[i] = new TabPanel();
tabs[i].HeaderText = "Tab "+i.ToString();
tabs[i].ID = "tabs" + i.ToString();
tabs[i].BorderWidth = Unit.Pixel(0);
tc.Tabs.Add(tabs[i]);
}
rssprogress = new UpdateProgress();
rssprogress.ID = "rssprogress";
rssprogress.ProgressTemplate = new
MyTemplate(this.Page.ClientScript.GetWebResourceUrl(this.GetType(),
"RSSReaderAjax.activityanimation.gif"));
this.Controls.Add(rssprogress);
this.ChromeType =
System.Web.UI.WebControls.WebParts.PartChromeType.None;
base.OnInit(e);
}
This is our webpart property panel
We will now implement the CreateChildControls() functions which initializes all the Controls and places the Controls in controls collection in the correct order. The function also checks if the RSS url is given to the webpart and if not, disables the tab which renders the Tab invisible.
protected override void CreateChildControls()
{
base.CreateChildControls();
#region Ajax_start
EnsurePanelFix();
rsspanel = new UpdatePanel();
rsspanel.ID = "rsspanel";
rsspanel.UpdateMode = UpdatePanelUpdateMode.Conditional;
rsspanel.ChildrenAsTriggers = true;
ajaxtimer = new Timer();
ajaxtimer.Enabled = true;
ajaxtimer.ID = "ajaxtimer";
ajaxtimer.Interval = UpdateInterval*1000;
#endregion
string content = "<script language="'javascript'"> " + togglescript
+ "</script>";
System.Web.UI.ScriptManager.RegisterClientScriptBlock(Page,
this.GetType(), "madhur", content, false);
plusimage =
this.Page.ClientScript.GetWebResourceUrl(this.GetType(),
"RSSReaderAjax.plus.gif");
minusimage =
this.Page.ClientScript.GetWebResourceUrl(this.GetType(),
"RSSReaderAjax.minus.gif");
string css =
this.Page.ClientScript.GetWebResourceUrl(this.GetType(),
"RSSReaderAjax.StyleSheet.css");
string link = "<link rel='stylesheet' type='text/css' href='" +
css + "'/>";
Page.Header.Controls.Add(new LiteralControl(link));
rsspanel.ContentTemplateContainer.Controls.Add(tc);
rsspanel.ContentTemplateContainer.Controls.Add(ajaxtimer);
for (int i = 0; i < 4; ++i)
{
if (GetRSSUrl(i) == null)
{
tc.Tabs[i].Enabled = false;
tabs[i].Controls.Add(new LiteralControl("Please specify
the URL of the RSS feed in webpart properties.<br>"));
}
else
{
rsstext[i] = new Label();
rsstext[i].ID = "rsstext" + i.ToString();
rsstext[i].Text = RSSBind(GetRSSUrl(i),i);
tabs[i].Controls.Add(rsstext[i]);
}
}
this.Controls.Add(rsspanel);
AjaxControlToolkit.UpdatePanelAnimationExtender anim = new
UpdatePanelAnimationExtender();
anim.ID = "anim";
anim.TargetControlID = rsspanel.ID;
}
Lets now implement our final function, which will take the RSS Url and will return a string
containing the formatted RSS output. The returned string will make Use of image url and rss, which have been specified in the webpart. The function will call the GetFeeds() function defined above to retrieve the feeds and format it properly so that they are ready
to be rendered.
public string RSSBind(string url,int index)
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
System.Data.DataSet ds = RSSRead.GetFeeds(url);
if (ds.Tables.Count == 1)
{
sb.Append("Error occured: " +
ds.Tables[0].Rows[0][0].ToString());
return sb.ToString();
}
System.Data.DataTable dtFeeds = ds.Tables[0];
System.Data.DataTable info = ds.Tables[1];
int count = 1;
string divnonestyle = "style=display:none";
string divid = string.Empty;
string parentdivid = string.Empty;
string funccall = string.Empty;
sb.Append("<table>");
sb.Append("<tr>");
string s = GetRSSImage(index);
if (!string.IsNullOrEmpty(s))
{
sb.Append("<td width='"+ImgPanelWidth+"' valign='top'>");
sb.Append("<img src='" + GetRSSImage(index) + "'
valign='top'/>");
sb.Append("</td>");
}
sb.Append("<td>");
foreach (System.Data.DataRowView drv in dtFeeds.DefaultView)
{
divid = this.ID+index.ToString()+ count.ToString();
parentdivid = "ctl_" + divid;
funccall = "javascript:ToggleItemDescription('" + divid +
"','" + plusimage + "','" +minusimage + "')";
sb.Append("<table>");
sb.Append("<tr>");
sb.Append("<td>");
sb.Append("<img onclick=" + funccall + " valign=bottom
border=0 style='cursor:hand;'id=\"" + parentdivid + "\" src=\"" + plusimage +
"\"/>");
sb.Append("</td>");
sb.Append("<td>");
sb.Append("<a href=\"" + funccall+"\">" +
drv["Title"].ToString() + "</a>");
sb.Append("</td>");
sb.Append("</tr>");
sb.Append("</table>");
sb.Append("<div id=\"" + divid + "\"" + divnonestyle + ">");
drv["Content"] =
drv["Content"].ToString().Replace("<b>Body:</b>", string.Empty);
drv["Content"] = drv["Content"].ToString().Replace('Â', ' ');
sb.Append(drv["Content"].ToString());
sb.Append("Published on: " + drv["PublishDate"].ToString());
sb.Append("</div>");
count++;
}
sb.Append("<a href=\"" + info.Rows[1][0].ToString() +
"\"><br>Click here to View all items</a><br>");
sb.Append("</td>");
sb.Append("</tr>");
sb.Append("</table>");
int j=info.Rows[0][0].ToString().IndexOf(':');
if (j != -1)
tc.Tabs[index].HeaderText =
info.Rows[0][0].ToString().Substring(j + 2);
else
tc.Tabs[index].HeaderText = info.Rows[0][0].ToString();
return sb.ToString();
}
I have tried to make the webpart as simple as possible. Some of the points to be worth noted:
