Intentionally left blank.The document root element is not supported by the visual designer.

if ur xaml is not blank and has controls
close VS , open VS and build the whole solution.
the error wil vanish :)

"Invalid index. (Exception from HRESULT: 0x8002000B (DISP_E_BADINDEX))"

That is because the parameters (or parameters names) you set in your code are different from defined parameters in your report

Unable to find the report in the manifest resources. Please build the project, and try again

This error occurred to us when we were trying to run a crystal report in Silverlight 4.
The report was put in a folder with name 'MTS Reports'.
When the space in the folder name was removed and renamed as 'MTS_Reports' in the .cs file of the added crystal report and after we rebuilt the application, the error was resolved.

Hope This Helps. 

|,|| and &,&& in C#

The && and || operators in C# work very similarly to their And and Or counterparts (& and | in C#).
The difference is that with these operators the second expression is never evaluated
when the first one already determines the outcome of the entire expression
eg: if (userName == “Administrator” && GetNumberOfRecordsFromDatabase() > 0)

Now, GetNumberOfRecordsFromDatabase() will only be executed when the current user is
Administrator. The code will be ignored for all other users, resulting in increased performance for them.

&& in C# is equivalent to AndAlso in C#
|| in C# is equivalent to OrElse in C#

&& and || are not advisable if each and every expression is to be evaluated.

&&' and '||' are what's called "short-circuiting" logical operators.

In the case of &&, if the first operand is false, then it doesn't bother evaluating the second operand, because the whole expression is certain to be false.

In the case of ||, if the first operand is true, then it doesn't bother evaluating the second operand, because the whole expression is certain to be true.

'&' and '|' can also be used as logical operators though it's more common for them to be used as bitwise operators. When they're used as logical operators, both operands are always evaluated.

Using the InvariantCulture Property

The CultureInfo.InvariantCulture property is neither a neutral nor a specific culture. It is a third type of culture that is culture-insensitive. It is associated with the English language but not with a country or region. You can use InvariantCulture in almost any method in the System.Globalization namespace that requires a culture.

  // Parses the string stored in the file,
         // and stores it in a DateTime.
         DateTime dtout = DateTime.Parse(date, InvC);

         // Creates a CultureInfo set to "fr-FR".
         CultureInfo frc = new CultureInfo("fr-FR");
         // Displays the date formatted for the "fr-FR" culture.
         Console.WriteLine("\nThe date read from the file and formatted 
               for the culture \"fr-FR\" is:\n{0}" , dtout.ToString("d", 
               frc));

         // Creates a CultureInfo set to "ja-JP".
         CultureInfo jpn= new CultureInfo("ja-JP");
         // Displays the date formatted for the "ja-JP" culture.
         Console.WriteLine("\nThe date read from the file and formatted 
               for the culture \"ja-JP\" is:\n{0}" , dtout.ToString("d", 
               jpn));

The date read from the file and formatted for the culture "fr-FR" is:
24/07/2001

The date read from the file and formatted for the culture "ja-JP" is:
2001/07/24

Select all CheckBox in DataGrid and delete rows in Silverlight

http://www.c-sharpcorner.com/uploadfile/dpatra/select-all-checkbox-in-datagrid-and-delete-rows-in-silverlight-3/

RDLC in .NET framework - Date formatting

CDate(Fields!StartDate.Value) may not always work.

Format(Fields!StartDate.Value,"dd-MM-yyyy") - this works.

if StartDate.Value is string then First(Fields!StartDate.Value) works.

HTH,

Anju