How to copy from Collection of DataRows to DataTable if Collection is empty?

[Pedro_Pais]

Hey masters,

How can I copy from a Collection of DataRows to a DataTable if my collection is empty?
If the collection is not empty, it works with this assign: newPackagesCollection.CopyToDataTable, where newPackagesCollection is a System.Data.EnumerableRowCollection<System.Data.DataRow>. But it fails when the collection has no rows…
And when I try this, it also fails: if(newPackagesCollection.Count > 0,newPackagesCollection.CopyToDataTable, new System.Data.DataTable)

Assign: Can not assign ‘if(newPackagesCollection.Count > 0,newPackagesCollection.CopyToDataTable, new System.Data.DataTable)’ to ‘newPackageDT’.

Greetings,
Pedro Pais

[vignesh.ks]

Hi @Pedro_Pais

Please change the assign variable type to ‘DataType’ and try this method. Thanks.

Happy Automation.

Feel free to reach us at any time if you have doubts.

[Pedro_Pais]

Hi @vignesh.ks

I can’t assign to DataType, it doesn’t work.

[kumar.varun2 (Varun Kumar)]

@Pedro_Pais Does the empty collection have the column information? How are you generating/getting the the Collection of data rows? And what should be done if the Collection is empty?

Try this -

newPackageDT = if(newPackagesCollection.Count > 0, newPackagesCollection.CopyToDataTable, Nothing)

Even this will also work

newPackageDT = if(newPackagesCollection.Count > 0, newPackagesCollection.CopyToDataTable, New DataTable())

and if you want to retain the column information of a Data Table you can use this

newPackageDT = if(newPackagesCollection.Count > 0, newPackagesCollection.CopyToDataTable, exampleDT.Clone)

Important : Set Variable Type of newPakageDT as System.Data.DataTable

[ayush_purohit]

if you know the name of the columns of this collection, first set them. Try to add the rows after that.
It should resolve the issue.

[vignesh.ks]

Hi @Pedro_Pais

I tried this code in my Studio, I didn’t get any issue. Attached screen shot for your reference.

Correct me if I’m doing any mistake. Thanks.

Happy Automation

[Pedro_Pais]

I’m using this assign from the image to get new elements from comparing two existent datatables to an EnumerableRowCollection<System.Data.DataRow> and then copy to a new Datatable.

It works very well if there are new elements. But if the resulting Collection is empty, it doesn’t work, because there are no elements to copy to a dataTable.

I tried all the options @kumar.varun2 wrote here, before, and before copying to a DataTable, but none worked! The error appears in execution time.

I wanted to know how I can see if an EnumerableRowCollection<System.Data.DataRow> is empty before copying to a datatable… I can’t find a solution.

My solution: I put the code into a Try-Catch, and if an InvalidOperationException occurs, it says there are no new rows to copy. Not the best, but it works…

[Pedro_Pais]

I separated both variables in two different assigns, to see in which moment it breaks… And the message error is different now:

Error: Assign: Activity ‘1.103: VisualBasicValue’ cannot access this public location reference because it is only valid for activity ‘1.109: VisualBasicValue<EnumerableRowCollection>’. Only the activity which obtained the public location reference is allowed to use it.

What is that?

UPDATE: Now I see it must be inside a Multiple Assign to work…

[GersonTun]

Suggestion: Try first to assign the result to an array of rows.

Then if the array has more than 0 rows, use the copy to data table function.

That’s the easiest way I found to filter a table and handling the null values.
I sometimes want to do everything in a single line, but VB just does not allow me to do it, lol.
Hope this helps, let me know.

[Pedro_Pais]

Thank you, @GersonTun , well thought! It worked!

Greetings,
Pedro Pais