Archive for the ‘C# 2.0’ Category
Posted by jpluimers on 2013/09/24
When you call a DbDataAdapter.Update, and it throws an exception, the exception does not include the underlying Command and its parameters.
Since the DbDataAdapter can have three commands for applying changes (DeleteCommand, InsertCommand and UpdateCommand), asking those is a bit inconvenient.
The other way is to attach an event handler to the DAL specific RowUpdated event (for instance SqlDataAdapter.RowUpdated).
This is event is called from the virtual OnRowUpdatedMethod, and has a value parameter of type RowUpdatedEventArgs which contains the Command, and Errors that occurred. Errors is just the Exception that can help indicate what went wrong.
–jeroen
via: DbDataAdapter.Update Method System.Data.Common.
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 »
Posted by jpluimers on 2013/09/17
Igor Ostrovsky wrote a few very nice MSDN magazine articles. Not all of them have ended up in the list at MSDN magazine, so here is a more complete list:
Though the articles show the majority of sample code in C#, the actual topics are of great interest to any developer writing .NET code or interfacing to it.
Some keywords in his articles: Read the rest of this entry »
Posted in .NET, .NET 1.x, .NET 2.0, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, .NET CF, C, C#, C# 1.0, C# 2.0, C# 3.0, C# 4.0, C# 5.0, C++, Delphi, Development, F#, LINQ, PLINQ, Prism, Software Development, VB.NET, VB.NET 10.0, VB.NET 11.0, VB.NET 7.0, VB.NET 7.1, VB.NET 8.0, VB.NET 9.0 | Leave a Comment »
Posted by jpluimers on 2013/09/10
Just came across this nice answer by harpo containing a small class that can Escape/Unescape double-quotes in strings.
–jeroen
via: Good CSV Writer for C#? – Stack Overflow.
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, CSV, Development, Software Development | Leave a Comment »
Posted by jpluimers on 2013/08/29
When you have a layered exception handling (for instance to translate general exceptions into domain or business exceptions, and want to control which exceptions trickle up to where), then from a debugger perspective, most exceptions actually handled.
However debugging those layers, it often makes sens to be able to break where all these exceptions are actually fired.
The screenshots (click on each to enlarge) are for Visual Studio 2010, but it works in any Visual Studio version and (since it is a debugger feature, not a language one) for all .NET languages I tried so far.
Note that as of Visual Studio 2010, if you disable these, it still breaks when exceptions are thrown from code called through reflection. This seems intentional and has 3 workarounds, but it might have been reverted in Visual Studio 2012.
This is a setting stored on the Solution level (.suo file) in Visual studio which by default is turned off. Luckily, it is very easy to turn this feature on, for instance for CLR (.NET Common Language Runtime) exceptions:
- In the “Debug” menu, choose “Exceptions” (or Press Ctrl+D, E),
- Wait a few moments for the dialog to appear
- Put a checkmark in the “Thrown” column for the “Comon Language Runtime Exceptions” row.
- Click the “OK” button. Read the rest of this entry »
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, F#, Prism, Software Development, VB.NET, VB.NET 10.0, VB.NET 11.0, VB.NET 7.0, VB.NET 7.1, VB.NET 8.0, VB.NET 9.0 | 1 Comment »
Posted by jpluimers on 2013/08/08
Peter Leslie Morris asked if Delphi already incorporates the `yield` keyword that C# had introduced in C# 2.
Delphi doesn’t, but for the people interested what it does in C#:
Basically `yield` is syntactic sugar to make it a lot easier to write methods that return enumerators of some sort.
It delays (hence the yield keyword) execution until the enumerator as actually being used.
It is one of the hardest C# things to master (it is the most complicated transformation in the compiler, followed by anonymous methods – well maybe with the exception of async/await), but it can be very useful.
VB.NET doesn’t have it either (thanks André!) has it too, but and also has iterator blocks.
Some start posts on yield:
–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, Delphi, Development, Software Development | 10 Comments »
Posted by jpluimers on 2013/08/06
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, VB.NET, VB.NET 10.0, VB.NET 11.0, VB.NET 8.0, VB.NET 9.0, Visual Studio 11, Visual Studio 2010, Visual Studio and tools | 7 Comments »
Posted by jpluimers on 2013/08/03
If you ever get something similar to
InvalidCastException: [A]Person cannot be cast to [B]Person.
then you are (or more precise: your process is) probably loading the same assembly twice, but from a different context.
.NET allows that, and for reason (side by side loading, appdomains, etc).
Delphi doesn’t (thanks Warren Postma for noticing). But a mistake you see quite often is that Delphi developers try to load the same Delphi type from both an EXE and a DLL wondering why they don’t match. If you want to spread your types in Delphi, then use BPLs (run-time packages) for that. BPLs are similar to .NET assemblies, but cannot be loaded in memory twice.
–jeroen
via c# – InvalidCastException for two Objects of the same type – Stack Overflow.
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, VB.NET, VB.NET 10.0, VB.NET 11.0, VB.NET 8.0, VB.NET 9.0, Visual Studio 11, Visual Studio 2005, Visual Studio 2008, Visual Studio 2010, Visual Studio and tools | Leave a Comment »
Posted by jpluimers on 2013/07/25
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, Delphi, Delphi XE2, Delphi XE3, Development, Software Development | 4 Comments »
Posted by jpluimers on 2013/07/23
Ever since I started .NET programming after .NET Beta 1 Arrived in 2001, I found that many people struggle with the relation between assemblies and namespaces.
So I was glad that I posted this answer about 2.5 years ago on StackOverflow. Below is the slightly edited form:
People are easily confused by the namespace/assembly thing, as it decouples the concept of where your code is physically located (the assembly) and how you reference it:
- logically reference is by using the namespace
- physical reference is by referencing the assembly
I usually explain the relation using the word contribute:
- An assembly can contribute to multiple namespaces.
For instance, the System.Data.dll assembly contributes to namespaces like System.Data (e.g. the class System.Data.DataTable) and Microsoft.SqlServer.Server (e.g. the class Microsoft.SqlServer.Server.SqlContext).
- Multiple assemblies can contribute to a single namespace.
For instance both the System.Data.dll assembly and the System.Xml.dll assembly contribute to the System.Xml namespace.
Which means that if you use the System.Xml.XmlDataDocument class from your project, you need to reference the System.Data.dll assembly.
And if you use the System.Xml.XmlDocument class, you need to reference the System.Xml.dll from your project.
(the above examples are .NET 4.0, but likely hold for previous .NET versions as well).
Danny Thorpe explained the concept of namespace and internal really well, so I won’t go into detail about those.
Ever since I started .NET courses 10 years ago, I draw a table explaining assemblies and namespaces like this:
–jeroen
via: C# assemblies, whats in an assembly? – Stack Overflow.
Posted in .NET, .NET 1.x, .NET 2.0, .NET 3.0, .NET 3.5, .NET 4.0, .NET 4.5, .NET CF, C#, C# 1.0, C# 2.0, C# 3.0, C# 4.0, C# 5.0, Development, Software Development | Leave a Comment »
Posted by jpluimers on 2013/07/18
A while ago, I wrote about .NET/C# duh moment of the day: “A char can be implicitly converted to ushort, int, uint, long, ulong, float, double, or decimal (not the other way around; implicit != implicit)”.
There is another duh moment having to do with the various C# operators like += which is being described as being
a += b
is equivalent to
a = a + b
You might think that this also holds:
a += b + c
is equivalent to
a = (a + b) + c
But Eric Lippert has explained this is not the case: it is equivalent to:
a = a + (b + c)
In his explanation, he also shows the confusion can get you very surprising results if you mix string, chars and ints in the expression: depending on the statement and ordering, you either concatenate characters, or add ints to characters.
He also recommends you should not do concatenation: either use String.Format, or StringBuilder. I totally agree with that.
Recommended reading!
–jeroen
Posted in .NET, 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 