Archive for the ‘C# 2.0’ Category
Posted by jpluimers on 2014/04/22
The first bulleted link below has been living in my drafts like forever (i.e. somewhere since mid June 2009), so time to write a bit about ISO 8601 and .NET.
First a few links about converting a DateTime into ISO 8601 string format:
Some solutions use the “K” as a time zone specifier. At first, I couldn’t find any documentation for it, not even Google Search for Google Search for “ssK” DateTime ToString returns anything useful.
Later on, I found The “K” Custom Format Specifier in Custom Date and Time Format Strings.
So my preferred solutions for me are these:
System.DateTime.Now.ToString("yyyy-MM-ddTHH:mm:ssK");System.DateTime.Now.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssK");
I avoid these:
System.DateTime.Now.ToString("o");
because it gets you too many digits in the second fracion.System.DateTime.Now.ToUniversalTime().ToString("s") + "Z";
because it is less clear what it does (might be resolved with a comment).
–jeroen
–jeroen
Posted in .NET, .NET 2.0, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, C#, C# 2.0, C# 3.0, C# 4.0, C# 5.0, Development, ISO 8601, Software Development | 1 Comment »
Posted by jpluimers on 2014/04/17
Thanks User Andrew Hare – Stack Overflow for answering this on Stack Overflow.
I’m pretty sure it works in all .NET and C# versions starting with 2.0.
Here is a hack-ish way to do it without having to load the entire output string into an XmlDocument: Read the rest of this entry »
Posted in .NET, .NET 2.0, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, C#, C# 2.0, C# 3.0, C# 4.0, C# 5.0, Development, Software Development | Leave a Comment »
Posted by jpluimers on 2014/04/16
Posted in .NET, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, ASP.NET, C#, C# 2.0, C# 3.0, C# 4.0, C# 5.0, Development, Software Development, Visual Studio 11, Visual Studio 2008, Visual Studio 2010, Visual Studio 2013, Visual Studio and tools | Leave a Comment »
Posted by jpluimers on 2014/04/15
Posted in .NET, .NET 2.0, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, ASP.NET, C#, C# 2.0, C# 3.0, C# 4.0, C# 5.0, Development, Fiddler, Software Development, Visual Studio 11, Visual Studio 2005, Visual Studio 2008, Visual Studio 2010, Visual Studio and tools, Web Development | Leave a Comment »
Posted by jpluimers on 2014/04/09
Interesting read:
The C language specification describes an abstract computer, not a real one – The Old New Thing – Site Home – MSDN Blogs.
In other words: any language that merges null behaviour in the underlying storage will have a problem somwehere.
So if you want to have true nullable types, your null flag should be stored outside the underlying storage.
The .NET framework 2 and up, most database management systems and many other environment support that.
But most languages don’t support it for pointer types. So there will be portions of address spaces either inaccessible, or only accessible when skipping the null pointer checks.
Note that the thread above contains some very interesting bits, for instance this one:
Matt 28 Mar 2013 5:58 PM #
@MarkY “Dereferencing null is undefined? Cool! I thought it was guaranteed to crash, just like a false assertion or something. So crashing is the OS guarantee, not the language guarantee apparently.”
Nope. It’s not an OS guarantee either. The OS won’t ever normally allocate memory at address zero, but there’s nothing to stop you telling it to. Try doing “VirtualAlloc(1, 4096, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE)” on your pre-Windows8 machine.
In fact, this is the reason why null-dereferences in kernel mode are often exploitable as elevation of privilege attacks. The null-page is mappable and within the user-addressable region of memory, so if the kernel dereferences a null pointer, it reads attacker controllable data.
And btw, this is the reason why on Linux and Windows8+ you can’t map the null-page.
–jeroen
via: The C language specification describes an abstract computer, not a real one – The Old New Thing – Site Home – MSDN Blogs.
Posted in .NET, .NET 2.0, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, Borland C++, Borland Pascal, C, C#, C# 2.0, C# 3.0, C# 4.0, C# 5.0, C++, C++ Builder, Database Development, Delphi, Development, Pascal, Quick Pascal, Software Development, Turbo Pascal, VB.NET, VB.NET 10.0, VB.NET 11.0, VB.NET 8.0, VB.NET 9.0 | Leave a Comment »
Posted by jpluimers on 2014/04/02
Every once in a while, someone hoses their computer far enough that it has to be reinstalled, but the original Microsoft product keys are misplaced, and some creepy anti-virus tool disallows the running of standard product key recovery tools like nirsoft’s.
Well, there is enough sourcecode that does recover it, just look for any of these strings:
Some hits:
The below full executables can trigger a virus warning (ordered from less often to most often):
–jeroen
Posted in .NET, .NET 2.0, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, C#, C# 2.0, C# 3.0, C# 4.0, C# 5.0, CommandLine, Delphi, Development, PowerShell, Software Development | Leave a Comment »
Posted by jpluimers on 2014/03/24
When using a FlowLauyoutPanel, I always forget on which control the FlowBreak design time property / SetFlowBreak run time method operates.
Then I always end up writing a short demo program like Container Controls 5: FlowLayoutPanel.
It operates after the control on which you set it.
It is like text in a Word Processor: it breaks after the place where you set the break. Read the rest of this entry »
Posted in .NET, .NET 2.0, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, C#, C# 2.0, C# 3.0, C# 4.0, C# 5.0, Development, Software Development, WinForms | Leave a Comment »
Posted by jpluimers on 2014/03/13
Listen to Podcast 106: Shipping | iDeveloper.
A few notes:
- RemObjects C# on iOS is based on LLVM, so I assume the other platforms use that too.
- Both guys are really busy shipping stuff, and it is hard.
–jeroen
Posted in .NET, C#, C# 1.0, C# 2.0, C# 3.0, C# 4.0, C# 5.0, Development, RemObjects C#, Software Development | 2 Comments »
Posted by jpluimers on 2014/03/07
Nice video when using either of the RemObjects Elements (Oxygene or Hydrogene): for creating a UI UINavigationController – remobjects.
–jeroen
Posted in .NET, C#, C# 1.0, C# 2.0, C# 3.0, C# 4.0, C# 5.0, Development, Oxygene, Pascal, RemObjects C#, Software Development | Leave a Comment »
Posted by jpluimers on 2014/02/11
The DBNull type is a very special type in .NET. It represents null values in databases, which are slightly different than null values in .NET.
The biggest confusion that people have with it is that it won’t convert to anything. Which means that you see a lot of questions like “System.InvalidCastException: Conversion from type ‘DBNull’ to type” “is not valid”.
You’d think the full name would be System.Data.DBNull, it is actually named System.DBNull. The reason is that various other functionality of the System namespace depend on it, for instance the System.Convert class.
DBNull was already present in .NET 1.x, so it predates nullable types that were introduced in C# 2 / .NET 2.
A null value on the database side will result in a DBNull instance.
If you want to explicitly pass a null value to a database, you use a DBNull.Value, which is a singleton.
Why DBNull
There is a very interestin question/answer series on StackOverflow about this: via .net – What is the point of DBNull? – Stack Overflow.
There are a few good arguments both for and against DBNull.
But the baseline is that DBNull predates the introduction in the .NET framework of genuine nullable types. Both their behaviour is slightly different, so DBNull had to stay.
Which means you have to deal with it every now and then.
Invalid casts
A bit more background on the invalid casts.
It is thrown like this:
throw new InvalidCastException(Environment.GetResourceString("InvalidCast_DBNull"));
from
Convert.DefaultToType();
which is called from the DBNull method
object IConvertible.ToType(Type type, IFormatProvider provider);
All other IConvertible methods are implementated like
bool IConvertible.ToBoolean(IFormatProvider provider)
{
throw new InvalidCastException(Environment.GetResourceString("InvalidCast_FromDBNull"));
}
So these all throw the same exception:
bool IConvertible.ToBoolean(IFormatProvider provider);
byte IConvertible.ToByte(IFormatProvider provider);
char IConvertible.ToChar(IFormatProvider provider);
DateTime IConvertible.ToDateTime(IFormatProvider provider);
decimal IConvertible.ToDecimal(IFormatProvider provider);
double IConvertible.ToDouble(IFormatProvider provider);
short IConvertible.ToInt16(IFormatProvider provider);
int IConvertible.ToInt32(IFormatProvider provider);
long IConvertible.ToInt64(IFormatProvider provider);
sbyte IConvertible.ToSByte(IFormatProvider provider);
float IConvertible.ToSingle(IFormatProvider provider);
ushort IConvertible.ToUInt16(IFormatProvider provider);
uint IConvertible.ToUInt32(IFormatProvider provider);
ulong IConvertible.ToUInt64(IFormatProvider provider);
–jeroen
via:
Posted in .NET, .NET 1.x, .NET 2.0, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, C#, C# 1.0, C# 2.0, C# 3.0, C# 4.0, C# 5.0, Development, Software Development | Leave a Comment »
The Wiert Corner - irregular stream of stuff 