One of the best to graphs diagrams of LINQ I know is in Mastering C# – Lecture Notes Part 2 of 4 – CodeProject [WayBack]
The LINQ explanation in that article [WayBack] is top notch as well. Thanks Florian Rappl [WayBack]!
–jeroen
Archive for the ‘C# 2.0’ Category
Great diagram on composing a LINQ query – via Mastering C# – CodeProject
Posted by jpluimers on 2017/08/17
Posted in .NET, C#, C# 2.0, C# 3.0, C# 4.0, C# 5.0, C# 6 (Roslyn), Development, Software Development | Leave a Comment »
.NET/C# some links on querying the ActiveDirectory
Posted by jpluimers on 2016/12/15
Without dsquery installable, I had to query an ActiveDirectory spanning two domains.
Here are some links that helped:
- Howto: (Almost) Everything In Active Directory via C# – CodeProject.
- c# – How to query Active Directory for all groups and group members? – Stack Overflow
- c# – Difference between PrincipalSearcher.FindAll() and GroupPrincipal.FindByIdentity() – Stack Overflow
–jeroen
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Yes Dorothy, the .NET System.Array Class can throw you a NotSupportedException
Posted by jpluimers on 2016/09/21
It’s been in the System.Array class forever, but remarkably few people do know that it can throw you a NotSupportedException (for instance when calling Add, Insert, Remove, etc).
It does because it implements IList, but not all methods implemented from IList are valid.
And it also indicates that, as the IList Properties allows for IsFixedSize to return false.
A similar case is there for IsReadOnly: then you cannot even modify the values.
Ever since I started teaching .NET/C# classes almost 15 years ago, I warned:
beware when you use IList as not everybody implements all methods.
–jeroen
via:
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.NET/C#: two ways of creating an empty array
Posted by jpluimers on 2016/08/18
Empty arrays are not used often as arrays usually are about the presence data, not about the absence.
Here are two ways based on the int data type in C# (the original [WayBack] examples [WayBack] are using string, but since string itself is also a kind of array…):
Specify a size of zero:
int[] a = new int[0];
Specify an empty initialisation:
int[] a = new int[] { };
Though many people think arrays are a thing of the past, I think it is one of the first generic types and have their place. For one, enumerating over arrays using foreach is a lot faster in many environments than enumerating over other data types. Another thing is that the fixed nature of arrays can be very beneficial in setting constraints.
That’s why I like the balanced view from Eric Lippert [WayBack] in Arrays considered somewhat harmful – Fabulous Adventures In Coding – Site Home – MSDN Blogs [WayBack]
–jeroen
via:
- How to initialize empty array in C# – Stack Overflow [WayBack]
- .net – How and when to abandon the use of arrays in C#? – Stack Overflow [WayBack]
- .net – Performance of Arrays vs. Lists – Stack Overflow [WayBack]
- c# – Faster enumeration: Leveraging Array Enumeration – Stack Overflow [WayBack]
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C#, XSD.exe, xsd2code and generating nullable fields+properties from an XSD with and without Specified fields/properties
Posted by jpluimers on 2016/07/27
It comes down to these cases for XML elements having maxOccurs="1" (which the default for maxOccurs):
- adding
nillable="true"will convert from a regular type to a nullable type. - adding
minOccurs="0"will add boolean …Specified properties in the generated C# for each element. - you can have both
nillable="true"andminOccurs="0"in an element which gets you a nullable type and a …Specified property.
Note I’m not considering
fixedordefaulthere, norattributes(that haveuseinstead ofminOccurs/maxOccurs, but do not allow for nillable) nor larger values ofmaxOccurs(which both xsd.exe and xsd2code regard asunbounded).
From the above, XML has a richer type system than C#, so in XML there are subtle a differences between:
- an explicit
nilin the XML element - the XML element being absent
- the XML element being empty.
Hopefully later more text and examples to show how to actually work with this.
- XML Schema nillable=”true” vs minOccurs=”0″ | Dimuthu’s Blog.
- Web services tip: Representations of null in XML Schema.
- c# – Nullable value with xsd.exe genereated class – Stack Overflow.
- Simon Fell > Its just code > Nullable and XxxSpecified.
- Knucklebones: How to NOT use XSD.EXE (it mentions xsd2code which is maintained and XmlGen# which is not maintained).
- Nullable type and XML xsd.exe tool – .NET Development – Windows Tech (xsd.exe .NET DataSets code generation don’t support Nullable).
- c# – Comparison of XSD Code Generators – Stack Overflow.
- .net – Serialize nullable type to optional non-nillable element – Stack Overflow.
- c# – Setting minOccurs=0 in a WSDL using “Specified” pattern not working – Stack Overflow.
- c# – Is it valid to set nillable=true and use the default property in an XML document? – Stack Overflow.
- xml – nillable and minOccurs XSD element attributes – Stack Overflow.
- Web services tip: Representations of null in XML Schema.
- XSD tool appends “Specified” to certain properties/fields when generating C# code – Stack Overflow: watch for semantics differences between C# and XML.
- Using the *Specified Properties in Exchange 2010.
- Name of the blog | Xml Serialization.
- c# – Nullable value with xsd.exe genereated class – Stack Overflow.
Delphi related to minOccurs:
- [WayBack] Problem with optional parameters in a remote function – delphi
- Wayback Machine QC 24056 is unavailable
- [WayBack] QualityCentral 73096 – Reported – Missing empty line in auto-generated code for node collections
- [RSP-16448] WSDL Importer has problems with tags in berlin – Embarcadero Technologies
- [RSP-19690] XML Data Binding Wizard creates wrong datatype – Embarcadero Technologies
- [WayBack] Delphi XML binding wizard and optional elements – Stack Overflow
Note that xsd2code.codeplex.com (unlike XmlGen#) has at least two forks at github:
From the specs:
- XML Schema Part 0: Primer Second Edition.
- XML Schema Part 1: Structures Second Edition.
- XSD.exe XML Schema Binding Support:
- XML Schemas (XSD) Reference:
–jeroen
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Easy way to generate “System.InvalidOperationException: Nullable object must have a value.”
Posted by jpluimers on 2016/07/07
Easy way to generate “System.InvalidOperationException: Nullable object must have a value.”.
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| using System; | |
| public class Test | |
| { | |
| public static void Main() | |
| { | |
| int? nullableInt = null; | |
| int nowInt = (int)nullableInt; | |
| } | |
| } |
–jeroen
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Did you know… How to change the build order for your solution? – #333 – Sara Ford’s Weblog – Site Home – MSDN Blogs
Posted by jpluimers on 2016/06/08
Boy I wish I had known this earlier. Like years ago…
In the Solution Explorer:
- Right Click Project
- Project Build Oder.
- Use the dialog to change the build order
It is next to the “Project Dependencies” in this image from Sara Ford:
Sara Ford: change “Project Build Order”
In the resulting dialog, you can change the build order within your solution.
This can be very useful when – for various reasons – you cannot have Project Level dependencies for an assembly, but have to have Assembly Reference dependencies for individual assemblies.
At a client I bumped into this, and this dialog was a life saver for us.
Others have used it because some Visual Studio versions miscalculate the dependencies.
–jeroen
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NHibernate, LINQ, Oracle and the placement of Take: avoid “Specified method is not supported.”
Posted by jpluimers on 2016/03/22
Even though as of 12c R1, Oracle supports a row limiting clause, NHibernate 4.2 with Oracle.DataAccess.dll 2.112.3.0 does not support that.
When you let it generate the SQL for a LINQ Take call to limit the number of results, you get an exception like this (full exception and stack trace are below):
System.NotSupportedException was unhandled by user code HResult=-2146233067 Message=Specified method is not supported.
The place where you Take is important, as this does fail:
Read the rest of this entry »
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Reminder to self: app.config and “ORA-12154: TNS:could not resolve the connect identifier specified”
Posted by jpluimers on 2016/03/17
When you have one app.config for your whole set of DTAP environments (develop/test/acceptance production), every once in a while you get this error:
ORA-12154: TNS:could not resolve the connect identifier specified
For this particular setup, it means the replacement of parameters in the app.config with actual values from the DTAP went wrong (or was missing). For that we’ve some steps in both the PreBuildEvent and PostBuildEvent of the .csproj file:
del "$(ProjectDir)$(TargetFileName).config"
copy "$(ProjectDir)app.config" "$(ProjectDir)$(TargetFileName).config"
powershell -noprofile -file Replace-Parameter.ps1 -Path "$(TargetDir)$(TargetFileName).config"
The PreBuildEvent looks like it is not needed, but sometimes Visual Studio forgets to perform the copy action.
–jeroen
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assembly:InternalsVisibleTo: .net – C# “internal” access modifier when doing unit testing – Stack Overflow
Posted by jpluimers on 2016/03/16
It seems I always forget about the InternalsVisibleTo attribute which allows you to specify which external assembly can see your internal types and type members:
Internal classes need to be tested and there is an assembly attribute:
using System.Runtime.CompilerServices;
[assembly:InternalsVisibleTo("MyTests")]Add this to the project info file, e.g. Properties\AssemblyInfo.cs.
Thanks Eric Schaefer for that answer.
–jeroen
via .net – C# “internal” access modifier when doing unit testing – Stack Overflow.
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The Wiert Corner - irregular stream of stuff 