Easy way to suppress code analysis warnings

2015-08-102016-01-30 TPodolak.NET, c#, code analysis

Everyone who has ever been using a code analysis knows that sometimes it is hard to follow the Microsoft coding guidelines and it is necessary to suppress some warnings. For me it always was a painful operation because I didn’t know any automated way of doing that. So basically I had to find the warning in the MSDN, copy category, code and other necessary stuff and then manually add appropriate attribute in code. Fortunately a friend of mine yesterday showed me a simple trick to generate this attribute with couple of mouse clicks. All you have to do is to right-click on warning message and choose Suppress Message context menu …

There are two options in there. The first option – In Source, will add attribute directly in the code

and the second one – In Suppression File, will create GlobalSuppressoins.cs file with assembly attribute which suppresses given warning in entire assembly

C# – testing internal classes

2015-07-262016-01-30 TPodolak.NET, c#, UnitTest

I am currently involved in writing library which will be used by couple of external teams. In that library we have a quite a lot classes which are only used internally and won’t be a part of public API. The natural way of keeping that code inaccessible for other assemblies is to use internal access modifier. However this makes the code also inaccessible directly for testing. Of course you can still test your internal code through public API but usually this is inconvenient and forces you to write a lot of additional code in test. This is particularly painful for me, because our build process requires 100% test coverage. Fortunately there is an easy way to make internal classes visible for certain assemblies without making them public. All you have to do is to use InternalsVisibleToAttribute and specify assembly name which is allowed to use code with internal access modifier. This attribute is most commonly added to AssemblyInfo.cs file. For example, assuming that my library is in TestingInternalClasses.Lib assembly and my tests are in TestingInternalClasses.Tests I should add

[assembly: InternalsVisibleTo("TestingInternalClasses.Tests")]

1	[assembly: InternalsVisibleTo("TestingInternalClasses.Tests")]

to AssemblyInfo.cs located in TestingInternalClasses.Lib project. However you can also use this attribute in a class definition file – just like that

using System;
using System.IO;
using System.Runtime.CompilerServices;
[assembly: InternalsVisibleTo("TestingInternalClasses.Tests")]

namespace TestingInternalClasses.Lib
{
    internal class VanillaSerializer : ISerializer
    {
        public Stream Serialize(object obj)
        {
            if (obj == null)
                throw new ArgumentNullException(nameof(obj));

            // rest of the code
            // ...
            // ...
        }

        public T Deserialize(Stream stream)
        {
            if (stream == null)
                throw new ArgumentNullException(nameof(stream));

            // rest of the code
            // ...
            // ...
        }
    }
}

using System;

using System.IO;

using System.Runtime.CompilerServices;

[assembly: InternalsVisibleTo("TestingInternalClasses.Tests")]

namespace TestingInternalClasses.Lib

{

internal class VanillaSerializer : ISerializer

{

public Stream Serialize(object obj)

{

if (obj == null)

throw new ArgumentNullException(nameof(obj));

// rest of the code

// ...

}

public T Deserialize(Stream stream)

{

if (stream == null)

throw new ArgumentNullException(nameof(stream));

// rest of the code

// ...

}

From now on I can easily test internal classes from TestingInternalClasses.Lib project in TestingInternalClasses.Tests. Source code for this post can be found here

Nested properties initialization – syntactic sugar

2015-04-182016-01-30 TPodolak.NET, c#

I think most of developers are familiar with the object syntax initializer, which basically allows you to set up values of properties just like that

var webClient = new CustomWebClient
            {
                Settings = new CustomWebClientSettings
                {
                    Encoding = "UTF-8",
                    Method = "POST"
                }
            };

var webClient = new CustomWebClient

{

Settings = new CustomWebClientSettings

{

Encoding = "UTF-8",

Method = "POST"

}

};

In this example the Settings property is assigned with new instance of CustomWebClientSettings class. However for time to time we only want to change particular property of given nested property and leave rest of the object intact. Of course we can write it usual way

// we assume that CustomWebClient initialized Settings property in constructor
var webClient = new CustomWebClient();
webClient.Settings.Encoding = "UTF-8";
webClient.Settings.Method = "POST";

// we assume that CustomWebClient initialized Settings property in constructor

var webClient = new CustomWebClient();

webClient.Settings.Encoding = "UTF-8";

webClient.Settings.Method = "POST";

but there is a much cooler syntax for that. The code above can be rewritten to

var webClient = new CustomWebClient
            {
                 Settings = {Encoding = "UTF-8", Method = "POST"}
            };

var webClient = new CustomWebClient

{

Settings = {Encoding = "UTF-8", Method = "POST"}

};

Note that there is no new keyword in the assignment of Settings property, which means that the Settings object is updated with the values of properties in braces. Of course this syntax can be safely used only if the nested property(in this case Settings) is initialized up front in constructor, otherwise you will get NullReferenceException. Source code for this post can be found here

NHibernate – generating WHERE IN … OR … queries

2014-08-182016-01-30 TPodolak.NET, c#, Disjunction, Nhibernate, QueryOver, Restrictions

Let’s assume that we have a simple table GL_Task which looks like this

I was asked to rewrite simple SQL query

SELECT Id,Name,IdProject FROM GL_Task WHERE Name = 'First task' OR Id IN (3,4 /*more id's to come*/)

1	SELECT Id,Name,IdProject FROM GL_Task WHERE Name = 'First task' OR Id IN (3,4 /more id's to come/)

using NHibernate’s QueryOver API. As simple as it may seem, solution for this particular problem is not straightforward. My first (not so clever) attempt was simply combining WhereRestrictionOn and Where clause

var result = session.QueryOver<Task>().Where(val=> val.Name == "First task")
                                      .WhereRestrictionOn(val=> val.Id)
                                      .IsIn(new []{3,4})
                                      .List();

var result = session.QueryOver<Task>().Where(val=> val.Name == "First task")

.WhereRestrictionOn(val=> val.Id)

.IsIn(new []{3,4})

.List();

Of course this query returns wrong data because of the fact, that NHiberante by default “joins” queries using AND operator. So above query will result in generating something like that

SELECT Id,Name,IdProject FROM GL_Task WHERE Name = 'First task' AND Id IN (3,4 /*more id's to come*/)

1	SELECT Id,Name,IdProject FROM GL_Task WHERE Name = 'First task' AND Id IN (3,4 /more id's to come/)

After a little digging I managed to write appropriate query

var orRestriction = Restrictions.Or(
                         Restrictions.Where<Task>(val => val.Name == "First task"),
                         Restrictions.On<Task>(val => val.Id).IsIn(new[] { 3,4 }));

var result = session.QueryOver<Task>()
                    .Where(orRestriction)
                    .List();

var orRestriction = Restrictions.Or(

Restrictions.Where<Task>(val => val.Name == "First task"),

Restrictions.On<Task>(val => val.Id).IsIn(new[] { 3,4 }));

var result = session.QueryOver<Task>()

.Where(orRestriction)

.List();

Although this code generates correct SQL, it is hard to use it in case of many OR statements. For example, adding one more OR force us to write

var orRestriction = Restrictions.Or(
      Restrictions.Or(
            Restrictions.Where<Task>(val => val.Name == "First task"),
            Restrictions.On<Task>(val => val.Id).IsIn(new[] {3, 4}) 
       ),
       Restrictions.On<Task>(val => val.Name).IsIn(new[] {"FirstTask", "SecondTask"})
);

var result = session.QueryOver<Task>()
                    .Where(orRestriction)
                    .List();

var orRestriction = Restrictions.Or(

Restrictions.Or(

Restrictions.Where<Task>(val => val.Name == "First task"),

Restrictions.On<Task>(val => val.Id).IsIn(new[] {3, 4})

Restrictions.On<Task>(val => val.Name).IsIn(new[] {"FirstTask", "SecondTask"})

);

var result = session.QueryOver<Task>()

.Where(orRestriction)

.List();

In my opinion this is a little bit hard to read, so I continued my searching to find more elegant solution. My third attempt was based on Restrictions.Disjunction

var disjunctinos = Restrictions.Disjunction()
                           .Add(Restrictions.Where<Task>(val => val.Name == "First task"))
                           .Add(Restrictions.On<Task>(val => val.Id).IsIn(new[] { 3,4 }));
                           
var result = session.QueryOver<Task>()                    
                    .Where(disjunctinos)                    
                    .List();

var disjunctinos = Restrictions.Disjunction()

.Add(Restrictions.Where<Task>(val => val.Name == "First task"))

.Add(Restrictions.On<Task>(val => val.Id).IsIn(new[] { 3,4 }));

var result = session.QueryOver<Task>()

.Where(disjunctinos)

.List();

This was almost perfect solution. Adding new OR statements do not require us to do function nesting

var disjunctinos = Restrictions.Disjunction()
                          .Add(Restrictions.Where<Task>(val => val.Name == "First task"))
                          .Add(Restrictions.On<Task>(val => val.Id).IsIn(new[] { 3,4 }))
                          .Add(Restrictions.On<Task>(val => val.Name).IsIn(new[] { "FirstTask", "SecondTask" }));

var result = session.QueryOver<Task>()
                    .Where(disjunctinos)
                    .List();

var disjunctinos = Restrictions.Disjunction()

.Add(Restrictions.Where<Task>(val => val.Name == "First task"))

.Add(Restrictions.On<Task>(val => val.Id).IsIn(new[] { 3,4 }))

.Add(Restrictions.On<Task>(val => val.Name).IsIn(new[] { "FirstTask", "SecondTask" }));

var result = session.QueryOver<Task>()

.Where(disjunctinos)

.List();

However the ultimate solution is to just add NHibernate.Criterion namespace and use IsIn extension method. This operation simplify our query into single lambda expression

var result = session.QueryOver<Task>()
                    .Where(val => val.Name == "First task" || val.Id.IsIn(new[] { 3,4 }))
                    .List();

var result = session.QueryOver<Task>()

.Where(val => val.Name == "First task" || val.Id.IsIn(new[] { 3,4 }))

.List();

Source code for this post can be found here

StringBuilder – removing trailing characters

2013-03-172016-01-30 TPodolak.NET, c#, StringBuilder

Today just quick tip about StringBuilder
I used to remove last character(s) from StringBuilder using Remove method.

 StringBuilder builder = new StringBuilder("some long text with comma,");
 builder.Remove(builder.Length - 1, 1);

1 2	StringBuilder builder = new StringBuilder("some long text with comma,"); builder.Remove(builder.Length - 1, 1);

However, recently I’ve came accross even simpler solution. You just need to lessen the Length property of StringBuilder, in order to get rid of last characters

StringBuilder builder = new StringBuilder("some long text with comma,");
builder.Length--;

1 2	StringBuilder builder = new StringBuilder("some long text with comma,"); builder.Length--;

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Easy way to suppress code analysis warnings

C# – testing internal classes

Nested properties initialization – syntactic sugar

NHibernate – generating WHERE IN … OR … queries

StringBuilder – removing trailing characters