The feature name XXX already exists in SharePoint. You need to rename the feature before solution deployment can succeed.

From time to time when I try to deploy a SharePoint project from Visual Studio 2005 I’m getting this error:

The feature name XXX* already exists in SharePoint. You need to rename the feature before solution deployment can succeed.

Whenever I get this (annoying) error I go to C:Program FilesCommon FilesMicrosoft Sharedweb server extensions12TEMPLATEFEATURES and remove the directory named …

Summary of Communities to Communities (C2C) 2009 Conference

C2C is a history now. I attended .NET stream and one session on SQL. The conference as a whole was very interesting, well organised, and basically developing. It was a Polish conference so most sessions were conducted in Polish but there were a couple of speakers from abroad too, and they spoke in English.

Basically I’m happy I had a …

MonoRail – RenderMailMessage – System.ArgumentNullException: Value cannot be null. Parameter name: format

This was a nasty issue…

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.ArgumentNullException: 
Value cannot be null.
Parameter name: format
   at System.String.Format(IFormatProvider provider, String format, Object[] args)
   at System.String.Format(String format, Object arg0, Object arg1)
   --- End of inner exception stack trace ---


This is part of the stack trace I got in one of …

.net, C#

System.IO.IOException: The process cannot access the file used as attachment with MailMessage

Recently I had to improve the mechanism of sending emails so that files can be attached to it. As I used MailMessage it seemed to be an easy task, especially that MSDN provided an example of how to do it. They assumed there that the file used as the attachment was already on the server and it shouldn’t be deleted …

Registering different versions of .NET Framwework

It’s possible to have more than one ASP.NET IIS installed and registrated on one machine (that runs Windows).
To check which version is currently registered run Command Line (Start/Run… and type ‘cmd’) and go to %SystemRoot%Microsoft.NETFrameworkvXXX directory where %SystemRoot% is a special system-wide environment variable found on Microsoft Windows NT and its derivatives (read more on Wikipedia) and vXXX is …

Robust generation of XML documentation comments for C#

Writing comments is something you need to get used to; sooner or later you will understand it’s worth writing comments. Haven’t you find yourself in a sitation where you don’t understand what a couple of lines of YOUR OWN code do? I have…

XML documentation comments are also important, particularly for public members/methods. Even if your project doesn’t require generating …

C#, decimal.toString(), and how to get rid of trailing zeros

Today I spend A LOT OF time on trying to display a percentage – string representation of a decimal but without trailing zeros, e.g. 15.1% instead of 15.10%.

In the application I already had NumberFormatInfo for displaying monetary values and percentages. An object of that type was defined as follows:

NumberFormatInfo nfi = new NumberFormatInfo();
nfi.PercentDecimalDigits = 2;
// some