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Great Reads

Your Quick Guide to Pattern Matching in C#

by Aram Tchekrekjian

More about pattern matching types with a usage example for each type

Faster than Reflection: Delegates. Part 3.

by n.podbielski

If you want to optimize code, which is based on Reflection, delegates may be the thing you are looking for. In this part are explained generic methods and events.

A Windows Service for moving and renaming scanned documents depending on file contents.

by Martin-Hallonqvist

This article describes how I wrote a small Windows service for handling the task of sorting and renaming scanned (and run throgh OCR) documents depending on contents.

Mapping Properties to String Keys

by Yuriy Magurdumov

PropertyMapper allows mapping object properties to string keys and accessing property values based on those string keys

Latest Articles

Your Quick Guide to Pattern Matching in C#

by Aram Tchekrekjian

More about pattern matching types with a usage example for each type

Into the Extreme – Fold-Expressions

by Coral Kashri

Fold-expressions in extreme cases

Translating C# Lambda Expressions to General Purpose Filter Descriptors & HTTP Query Strings

by Kamran Saeedi

An idea on how to use .NET ExpressionVisitor to translate lambda expressions into classes that encapsulate data suitable for filtering data & creating query strings

JavaScript IIFE Design Pattern

by Mayank_Gupta_

Immediately Invokable Function Expressions in JavaScript

All Articles

Expressions

Your Quick Guide to Pattern Matching in C#

11 Sep 2023 by Aram Tchekrekjian

More about pattern matching types with a usage example for each type

Faster than Reflection: Delegates. Part 3.

6 Sep 2016 by n.podbielski

If you want to optimize code, which is based on Reflection, delegates may be the thing you are looking for. In this part are explained generic methods and events.

A Windows Service for moving and renaming scanned documents depending on file contents.

14 Aug 2013 by Martin-Hallonqvist

This article describes how I wrote a small Windows service for handling the task of sorting and renaming scanned (and run throgh OCR) documents depending on contents.

Mapping Properties to String Keys

1 Oct 2014 by Yuriy Magurdumov

PropertyMapper allows mapping object properties to string keys and accessing property values based on those string keys

Dynamically creating a predicate delegate

29 May 2014 by Randy Kroeger

Created a POC that dynamically builds a predicate using Expression and Reflection.

Introduction to Functional Programming in Java 8 – Part Two

2 Jul 2014 by TheCannyCoder

Introduction to functional programming in Java 8

Evaluating an expression using DataTable.Compute() method throws error

20 Sep 2015 by PIEBALDconsult

Right, well obviously that method can't handle C/C++/C# syntax; it's actually pretty limited in what it can do.Fortunately, .net allows you to compile code at run-time. There are several articles here on CP, including mine: Compiling Source Code from a String[^]

regular-expression

REGEX: GET STring from Word"A" to Word"X" over more Rows

27 Aug 2015 by Zoltán Zörgő

STA(.*?)M2 is enough, but you need to enable Singleline[^].var s = @"STA;12345;325-5899ML;2222;5555;GHAA-;5881;2K5K1KKLM2;KKN;11232";var re = new Regex("STA(.*?)M2", RegexOptions.Singleline);Console.WriteLine(re.Matches(s)[0].Groups[1].Value);Yields:...

regular-expression

Get access to a parameter of a parent expression within expression tree.

26 Jul 2018 by Richard Deeming

The inner lambda expression will have access to the parameters from the outer lambda expression: var x = Expression.Parameter(typeof(Widget), "x"); var y = Expression.Parameter(typeof(Role), "y"); var z = Expression.Parameter(typeof(RoleAction), "z"); // z => !x.IsActive || z.IsActive var...

Expression to summarise column in RDLC report winform

2 Aug 2020 by Sandeep Mewara

You need to add a 'Total' row at the bottom of your report design instead of a column. Refer: Sum of Column Values in Reports Automatically Using Expression in .NET[^]

Evaluating an expression using DataTable.Compute() method throws error

20 Sep 2015 by Maciej Los

In addition to soultion 1 by PIEBALDconsult[^]...Computed column of DataTable object can accept quite difficult expression[^], but it is limited to these operators:ANDORNOT==INLIKEThe following arithmetic operators are also supported in expressions:+...

regular-expression

Expand string CAML queries via lambda expressions with Camlex.Net

4 Dec 2012 by sadomovalex

Shows how using reverse engineering feature developers may add new conditions into string CAML queries using lambda expressions.

Compare SSIS variable of Object data type to Null value in expression

27 Dec 2012 by shantanufrom4387

How can I compare a variable with NULL in SSIS expression?@[User::FilesExist]==Null

Need regex expression.

19 Jul 2013 by lewax00

The above ones seem like a bit much to me...how about just:^[^0]*$

Internationalization

11 Oct 2013 by ASP.NET Community

There are three terms around Internationalization that are often used interchangably, however they are distinctions. Here's a good

DLR : Expressions and a ‘Hello World’ application

11 Oct 2013 by ASP.NET Community

DLR Expression is the backbone of the DLR. It is a separate feature that you can use without involving the rest of the DLR.Let’s take a look at

Set Expressions DataTable

12 Mar 2014 by FarhanShariff

I want to put Minimum Value of (cpKL,cpKR) into cpK How to write the expression for cpKsigma.Expression = "(Convert(point90,'System.Double')-Convert(point10,'System.Double'))/2.56";cpKL.Expression = "(Convert(point50,'System.Double')-...

Building Conditional Expressions from Func...

23 Apr 2014 by Jens Madsen, Højby

Trying to get into Expressions, IL-Generated Delegates etc.I have this prototype for combining 'Comparisons', but I think it's quite slow, even with just 2-3 Funcs:(I use VB -- sorry ;) ) Public Function BuildCompareExpression(Of T)(exp1 As Expression(Of Func(Of T, T, Integer)), exp2...

How Do I Create A Call An Object's Property Which Is Of Delegate Type Using Expression

14 Sep 2014 by Simba Mukodzani

I have a piece of code like the following....Delegate Function CreateObject(Of I)(Object context) As IClass Container Property ReadOnly ObjectType() As TypeEnd ClassClass Container(of I) Inherits Container Property ReadOnly Creator() As CreateObject(Of I)End...

How to get IS NULL in expression (To get null values from database)

17 Nov 2014 by Prasaad SJ

Hi, I am using entity framework in my application. Consider I am having a following table structureEmployee(ID uniqueidentifier,Name varchar(100) not null,JobId uniqueidentifier null)I am using the following expression to get the dataExpression>...

How to get IS NULL in expression (To get null values from database)

17 Nov 2014 by Shweta N Mishra

replace the NULL with 0 in both side of where condition.something like Isnull(JobID,0)=Isnull(jobIdVariable,0).You would have to convert above expression as per the language requirement.

How to get IS NULL in expression (To get null values from database)

22 Nov 2014 by Prasaad SJ

After few trial attempts, I could find the solution for this question. If the type is of nullable type, then in expression we have use both Equals and == . Eg: In my above case in the question, its working correct when Expression> predicate;if(JobIdVariable==null){ ...

How to display multiple records using linq

28 May 2015 by Member 11581003

I have a table that stores Referral details - it includes fields like Referral Type, Referral Date, OffenderID, OfficerID etc.) And obviously some Offenders are referred more than once (multiple times) and likewise, OfficerID also repeats in the table as many offenders are referred by the same...

How to display multiple records using linq

28 May 2015 by Sascha Lefèvre

To give you a fully working query I would have to know how your Offender- and Officer-Tables/Entities look like. So I'll make a good guess here instead and to illustrate I include all the code I wrote to test it. You obviously can discard everything except the query at the bottom. I assume...

REGEX: GET STring from Word"A" to Word"X" over more Rows

27 Aug 2015 by Otsep

Hello Community,i need your help ;-)My input string:Row1: STA;12345;325-5899Row2: ML;2222;5555;GHAARow3: -;5881;2K5K1KKLRow4: M2;KKN;11232Now i want to get the string from "STA" to "M2".The following i tryed and it failed:STA(?s)([\S\s]*)M2Do you have a brillant...

regular-expression

Evaluating an expression using DataTable.Compute() method throws error

20 Sep 2015 by iSahilSharma

Update - I was trying to evaluate an expresion in C# using the DataTable.Compute() method and found that instead of using ternary operator(?,: ), I should've used the IFF(expression, truepart, falsepart). So I'm trying to convert the whole expression into the IFF format and need a little help to...

regular-expression

Understanding Arithmetic Expression Compilers

18 Nov 2015 by Oliver S. Neven

Hello there! (Sorry if I have some grammatical errors, english is not my native language, but I try my best!)I'm currently trying to write a program that compiles a string containing an arithmetic expression and solves / evaluates it. I'm not looking for code or libraries, I just want to get...

Understanding Arithmetic Expression Compilers

18 Nov 2015 by Patrice T

There is no solution/answer to your question.Quote:I could paste the code, but I see no point since I've just explained basically the whole program.This is where you are wrong. You gave us a vague general speak about expression compilation that can apply to almost any program or technique used...

Understanding Arithmetic Expression Compilers

20 Nov 2015 by Oliver S. Neven

I figured out how to do it by following these tutorials!https://www.youtube.com/watch?v=vXPL6UavUeA&list=LLAbEvqKZEqYBAmzzgVbKojQ&index=2[^]https://www.youtube.com/watch?v=MeRb_1bddWg&list=LLAbEvqKZEqYBAmzzgVbKojQ&index=3[^]Thanks for all your responds. :)

Get access to a parameter of a parent expression within expression tree.

26 Jul 2018 by Alex-1978

I'm working with Entity Framework and need to create filters dynamically in run time. I need to create an expression which should be able to access parameter of a parent call, e.g.: x => x.Roles.Select(y => y.Actions.Where(z => !x.IsActive || z.IsActive)) so that this filter should select _all_...

Get access to a parameter of a parent expression within expression tree.

25 Jul 2018 by Gerry Schmitz

"x" is in scope. class RoleAction { public bool IsActive; } class Role { public List Actions = new List(); } class Widget { public List Roles = new List(); public bool IsActive; } class Program { static...

Expression to summarise column in RDLC report winform

2 Aug 2020 by Member 14898617

In my RDLC report i am trying to create a table where i want summarise the count Containing YES & NO in "Issued_to_Maintanance" column. For this i have created first column by entering YES & NO manually and for the next column i have entered this...

Into the Extreme – Fold-Expressions

22 May 2023 by Coral Kashri

Fold-expressions in extreme cases

Translating C# Lambda Expressions to General Purpose Filter Descriptors & HTTP Query Strings

22 May 2020 by Kamran Saeedi

An idea on how to use .NET ExpressionVisitor to translate lambda expressions into classes that encapsulate data suitable for filtering data & creating query strings

Expression-Trees

Faster than Reflection: Delegates - Part 1

27 Feb 2017 by n.podbielski

If you want to optimize code, which is based on Reflection, delegates may be the thing you are looking for.

Faster than Reflection: Delegates. Part 2.

7 Apr 2017 by n.podbielski

If you want to optimize code, which is based on Reflection, delegates may be the thing you are looking for. In this part are explained methods and constructors.

29 Jan 2013 by Florian Rappl

An introduction to lambda expressions as well as an advanced discussion on how and where to use them. This article will also show known and introduce new design patterns that might be helpful.

An Introduction to Functional Programming with Java 8

14 Aug 2014 by TheCannyCoder

Java 8 is perhaps one of the most exciting editions of the Java language in recent times. One of the headline features is support for functional programming which is the focus of this blog. The support comes mostly in three features: Support for [work pipeline] streams. Streams allow us to process d

Everything That You Need to Understand about Lambda Expressions

15 Jan 2015 by Bhushan Mulmule

This write-up will take you through all the steps that are required to understand lambda expression thoroughly.

Support for IN CAML operation in Camlex

19 Nov 2013 by sadomovalex

Describes support for IN CAML operation in Camlex open source library for Sharepoint developers

JavaScript IIFE Design Pattern

15 Jun 2017 by Mayank_Gupta_

Immediately Invokable Function Expressions in JavaScript

Lambda Expressions

20 Dec 2015 by ASP.NET Community

Lambda expressions provide a concise, functional syntax for writing anonymous methods. They are super useful when writing LINQ query expressions.

Set Expressions DataTable

12 Mar 2014 by Manikandan K

then try separately, like this, first check which is smaller and assign that to a 3rd variable say cp,if(cpKL

Set Expressions DataTable

12 Mar 2014 by FarhanShariff

cpK.Expression = "IIF(cpKL

Set Expressions DataTable

12 Mar 2014 by Manikandan K

Try this, cpK.Expression = (cpKL

Need regex expression.

19 Jul 2013 by Arpit Shrivastava

Just add ^(?!0$)$ to your regular expression. It will not allow zeros at all...

Need regex expression.

19 Jul 2013 by ridoy

Check ^(?=.*[1-9])\d*\.?\d*$

Double checking my answer for solving a partition by statement

8 Nov 2021 by Arvin Donner

I am working on a partitioning problem. I am looking to partition an entire table using three different ranges: ColumnA > 0.0 ColumnA