.NET offers the simple
string.Join() methods for joining and splitting separated strings. But what if there is no suitable separator character that may not occur in the string? Then the separator character must be escaped. And then the escape character must be escaped too… And this turns out to be quite an interesting algorithm to write.
I thought that this functionality would be built in, but as far as I could find out it isn’t. If there is a built in way, please leave a comment to educate me. This being a string manipulation, there is a possibility to use Regular Expressions too, but…
Some people, when confronted with a problem, think “I know, I’ll use regular expressions.” Now they have two problems.
Solving this through a Regular Expression would require some black magic double look-behind assertion which I wouldn’t understand even when I wrote the code, much less later when I came back to fix some bug. So I went for implementing it myself.
Properties with non public setters sometimes make sense – until a unit test requires an object to be set up in a specific state. I don’t want to make the setter public just because of the tests, so I wrote a small helper function that can call non public setters.
The helper returns the object itself, to allow a fluent syntax inside member initialization expressions and uses a lambda to select the member (I do like compile time checking whenever it’s possible).
This is actual code I wrote last week using the helper. It’s part of a set up of an object collection used for unit tests.
Orders = new List<order>
OrderId = 983427,
}.CallNonPublicSetter(o => o.StatusId, OrderStatus.Confirmed),
OrderId = 18956,
}.CallNonPublicSetter(o => o.StatusId, OrderStatus.Delivered)
The helper is implemented using reflection to access the property to bypass the protection level of the setter.
This post is written by guest blogger Albin Sunnanbo. He’s a great friend and source of inspiration and also one of the best developers I know. It was Albin that first introduced me to LINQ, EF Migrations and jQuery that I now use daily.
I often find myself in situations where I need to update a collection property on some object in LINQ2SQL to match another collection property. Usually I get those collections to my data layer either from an import or from a complex update in the UI (via my business layer).
The most straight forward way to solve this is to clear all old items in the collection in the database and generate new items. Sometimes this is not possible when you have foreign key constrains and rows in other tables referring your collection items.
Many times I have written code where I try to figure out what items that are new, deleted or just updated and process them accordingly.
Today I finally wrote an extension method that encapsulates this pattern.
Recently I was involved in a problem where we had a WCF service referencing a 32 bit dll. The service was set to to “Start WCF Service Host when debugging another project in the same solution”. Unfortunately that ended up with an exception.
Could not load file or assembly ‘My32BitLib, Version=188.8.131.52, Culture=neutral, PublicKeyToken=null’ or one of its dependencies. An attempt was made to load a program with an incorrect format.
When a CLR process starts, the exe file determines if it will be loaded as a 32 or 64-bit process. In this case the
WcfSvcHost.exe is started as a 64-bit process, loads the service dll (compiled as “Any CPU”) and then fails when trying to load the My32BitLib assembly which is compiled as “x86”.
The solution is to create a special 32bit version of
WcfSvcHost and setup the debugging environment to use that instead of the standard
Often we cannot be sure if a parameter passed in to a function has a value. To write error safe code all those parameters have to be checked for
null and handled. We have the
?? coalesce operator to help, but still it can be quite a lot of code. Through the use of extension methods a lot of cases can be handled. As extension methods are in reality static methods of another class, they work even if the reference is
null. This can be utilized to write utility methods for various cases. In this post I’ll show two cases, one is an extension that returns a default value for an XML attribute value if the attribute or even the element is missing. The other one handles the common case when a
null sequence reference passed should be handled as an empty sequence.