Codeplex projects propose some cool free features including 3 master pages for SharePoint 2010 :

Apple.com Master Page

Metro UI Master Page

Buried Alive – Halloween Theme

Those could be apply to your sharepoint 2010 site and customized.
Download link : http://spmasterpage.codeplex.com/
Other codeplex projects : Useful tools for Sharepoint 2010 from Codeplex

Microsoft has published a SharePoint 2010 Code sample pack. Containing 101 Codes samples !
If I had that when i began to learn SharePoint, it would have saved me a lot of time.
Language are C# and VB, for SharePoint on premise AND Online !!

Some of really useful features are, for a sharepoint developper :

• Programmatically create masterpage for Sharepoint 2010, and apply the masterpage programmatically thanks to a Feature Event Receiver
• Programmatically create content type for Sharepoint 2010
• Create List definition for SharePoint 2010

Or some advanced one :

• Use Azure, WCF, Sharepoint Web service in Webpart, event receiver or Jobtimer

Here the complete list :

Thanks microsoft & msdn
Download link : http://code.msdn.microsoft.com/SharePoint-2010-101-Code-da251182

If you created a webtemplate based on any Site Definition (Team Site…) and if you comment the navbars part

What did i try to do ?

I’m creating SPListItem Programmatically (create elements in a list) and when the item.update(); is called by the code, the following error is thrown :
“Erreur : Valeur de date/d’heure non valide.Un champ de date/d’heure contient des données non valides. Vérifiez la valeur, puis réessayez”
or in english :
“SPException : invalid date/time…”

What could be the problem ?

1. The date format is not correct
2. The date is not correct (minimum date for SharePoint ?)

Solving the problem

I’m giving an example of an incorrect date value “01/01/0001 00:00:00” :

   1: SPList list = web.Lists["myList"];

   2:  

   3: SPListItem item;

   4: string date = "01/01/0001 00:00:00";

   5:  

   6: item = list.Items.Add();

   7:  

   8: item["currentDate"] = date;

   9: if (DateTime.TryParse(row["currentDate"].ToString(), out dateTime) == true)

  10: {

  11:     //si la date est définit

  12:     if (dateTime.ToString() != "01/01/0001 00:00:00")

  13:     {

  14:         item["currentDate"] = SPUtility.CreateISO8601DateTimeFromSystemDateTime(DateTime.Parse(date));

  15:     }

  16: }

  17:  

  18: item.update();

  19: list.update();

01/01/2001 is an incorrect value for a date in sharepoint.

And we check the date in order to respect sharepoint dates rules, using the method : CreateISO8601DateTimeFromSystemDateTime.

Have you ever had other issue with dates and SPListItem ?

What is that ?

Based on this excellent tutorial from kirk Evans : http://blog.evepoints.com/2010/11/add-video-sharepoint-2010-blog.html
This will allow you to add youtube video in a blog content.
Basic sharepoint feature permit you to add the video by modifying the HTML code, from the Insert HTML button of sharepoint, but that is not really user friendly.
Preview, on a blog post :

New youtube embedded format ?

I modified one of the method of Kirk Evans in order to accept the new youtube embedded video format. The new embedded video format looks like this :

New youtube embedded code for video (<iframe) :

Old youtube embedded code for video (object) :

So to update Kirk Evans code, replace the last method by :

   1: private string ReplaceEmbedsWithTokens(string body)

   2:         {

   3:             //VARS

   4:                 string returnString = null;

   5:                 //Old version of youtube embedded

   6:                 Regex rx = new Regex("(&lt;object).*?(&lt;embed src=&quot;)(?<src>.*?)(&quot;)(.*?)(&lt;/object&gt;)");

   7:

   8:             //CLEANING from a text editor

   9:             body = body.Replace("nr", " ");

  10:             body = body.Replace("rn", " ");

  11:

  12:             if (rx.IsMatch(body) == false)

  13:             {

  14:                 //New version of youtube embedded

  15:                 rx = new Regex("(&lt;iframe).*?(src=&quot;)(?<src>.*?)(&quot;)(.*?)(&lt;/iframe&gt;)");

  16:                 returnString = rx.Replace(body, "[[BLOGVIDEO: ${src}]]");

  17:                 returnString = returnString.Replace("embed", "v");

  18:             }

  19:             else

  20:             {

  21:                 //Old version of youtube embedded

  22:                 returnString = rx.Replace(body, "[[BLOGVIDEO: ${src}]]");

  23:             }

  24:

  25:

  26:             return returnString;

  27:         }

It also fix a bug : when you paste the embedded code in a word document in order to save it, and then you paste it in a blog, it won’t work properly.

Enjoy, and thanks again Kirk Evans

Issues :


After patching SharePoint 2010, with the cumulative Update of December, you could get some issues if you created custom content type by Visual Studio, using programmatically method (C#) :

• The document content type is missing
  • The error prompting on sharepoint is : 0x0101 is missing
• The element content type is missing :
  • The error prompting on sharepoint is : 0x01 is missing
• The error prompting : The parent content type specified by content type identifier 0x0…. does not exist

Solution : Here is the content type declaration in Visual Studio, this content type is added in a feature :

   1: <?xml version="1.0" encoding="utf-8"?>

   2: <Elements xmlns="http://schemas.microsoft.com/sharepoint/">

   3:   <ContentType ID="0x0101000726C67DDB280345872AA6FCED5762D104"

   4:                Name="CustomContentType"

   5:                Group="Custom Group"

   6:            Inherits="True"

   7:            Overwrite="True"

   8:                xmlns="http://schemas.microsoft.com/sharepoint/">

   9:     <Folder TargetName="_cts/CustomContentType" />

  10:     <FieldRefs>

  11:       <FieldRef ID="{8553196d-ec8d-4564-9861-3dbe931050c8}" Name="FileLeafRef" Required="TRUE" />

  12:     </FieldRefs>

  13: </Elements>

After the patch, this declaration won’t work, you’ll correct it by deleting “Inherits” and “Overwrite” attribute.           Inherits=”True”            Overwrite=”True”


[Edit 01/03/2012] : You’ll need to redeploy the .wsp package, or to modify directly in the /14 folder, the deployed content type + iisreset (not tested).


Did you have any other issue after the cumulative update of december 2011 for SharePoint 2010 ?

Problem

Launching a vm leaded me that message error : “Taking ownership of this virtual machine failed.

Resolution

The virtual machine is in use by an application on your host computer.

Configuration file” To solve the problem, delete lck files in the machine virtual folder content, search for : *.lck

I got the following error message in visual studio during programing :

“The file has been modified by … unknown”

It was because i called two times (by error) the item.update(); method.

This could happen as well when you code an event receiver (sometime happening when you do something on a list, web, site….) and you use item.update(), in order to fix that :

•  call and disable event firing before your code with : base.EventFiringEnabled = false;
• update your item by calling item.systemUpdate(false); 
• enable event firing with : base.EventFiringEnabled = true;