LINQ learning materials

[jitendra_123 (Jitendra Ughade)]

Hi @loginerror
I want to learn more about Linq how we can implement it in Uipath. If you have any documentation or any study material of it then please provide me.

[loginerror (Maciej Kuźmicz)]

Hi @jitendra_123

I made this topic public because the answer might also help others

LINQ expression is a big topic to cover at once. Some basic resources can already be found if you simply google for
linq
or maybe even
linq vb.net

In the context of UiPath, the easiest start is by looking at examples here on the Forum (by searching for linq on the forum)

I would start with simple expressions to achieve basic filtering and move on from there.

I hope other users can share their experience in the topic as well and some resources they used on the way

[sarathi125 (Parthasarathi)]

Hi,

To know/learn about Linq you can refer the below links

Intro to LINQ - Visual Basic

Writing Your First LINQ Query - Visual Basic

But at times when I want to write some complex linq queries I have used Visual Studio and test the query there before implementing it in UiPath.

[jitendra_123 (Jitendra Ughade)]

Hi @loginerror @sarathi125
Thank you for the reply but I will wait for some more users input as I need to know how exactly we can implement the syntax of LINQ queries in Uipath.

[Himanshu.joshi]

Hey @jitendra_123

just go through this Url which he provide in his post

Linq example in Uipath?

For usual Linq to SQL types you’d normally build at least entity classes, which is not possible in the UiStudio directly (they could be imported via packages though). Here is a great article from the creators of Linq to SQL that should give you a strong starting point. The logic itself is pretty simple, most of the work is building entity representations and queries themselves. As a sidenote - have you tried using existing DB activities? For simple cases they’re usually enough.

Cheers

[megharajky (Megharaj Yadravi)]

Hello,

I reffered https://www.tutorialsteacher.com/linq/linq-tutorials and felt its very good to learn from basics, you can also refere tutorials point, code project and stackoerflow for examples and scenarios.

Thanks,
Meg

[ppr (Peter Preuss)]

[HowTo] - First Start with LINQ (VB.Net)

LINQ is part of the .NET framework and offers capabilities for interacting with data, objects or other sources within a particular syntax. This HowTo introduces on starting with LINQ (Language-Integrated Query). Current Version of this topic is DRAFT and will be finalized / enhanced soon Introduction Typical tasks for implementing parts of an automation project are interacting with e.g. with data in a datatable or items from collections. LINQ can help to implement it into a compact and standa…

LINQSamples | LINQ 101 Query and Lambda Expression Samples

There are examples within the VB.Net Syntax available as well

[Yoshi_Akiyama (Yoshiya Akiyama)]

LinqSample.zip (12.1 KB)
I created a sample with LINQ that enumerate files 3 different ways.

1. ascending file names
2. descending file names
3. ascending file size
   Hope this helps.
   Please make sure to edit the variable that stores the directory to enumerate before running

[pattyricarte (Patty Boy)]

This is a good topic! I saw a lot of posts that needed this kind of information.I will bookmark it and once needed i will share it

cheers

Happy learning

[saiteja8 (saiteja)]

Hi @megharajky and all,

I learnt LINQ from TutorialsTeacher, but when iam trying to implement them in Uipath I am getting a weird error…not sure if my syntax is wrong because iam learning it through Uipath

I tried different validations using .equals, Is, = operator…but all gave the exception

Iam trying to execute:
dt.AsEnumerable.Where(function(s) s(“Screens”).ToString = in_ScreenName and s(“Field”).ToString = in_FieldName)

in_ScreenName - String Type and Value: “Screen1”
in_FieldName - String Type and value: “Field1”

result -
EnumerableRowCollection
{
!< ObjectDisposedException > …
}

Another Approach, I hardcoded the in_screenName and in_FieldName values like:
dt.AsEnumerable.Where(function(s) s(“Screens”).ToString = “Screen1” and s(“Field”).ToString = “Field1”)

result is - what I wanted (But why not through a variable in func? )
EnumerableRowCollection
{ DataRow
{
HasErrors=false,
ItemArray=object[4]
{ “First”, “F2”, 4, 11 }, RowError=“”, RowState=Added, Table=[ ] }
}

[megharajky (Megharaj Yadravi)]

Hello,

I tried the same and not getting any errors, please try the below code,

dt.AsEnumerable().Where( Function(s) s(“scfreens”).ToString=“Screen1” And s(“Feild”).ToString=“Feild1”).CopyToDataTable

[loginerror (Maciej Kuźmicz)]

Hi @saiteja8

What is the syntax error? You could try updating the activity packages to the latest version, it might fix the issue.

[Mala_Dinesh]

Thank you for the sample file. Very useful.