Automatically create IDs in repeating section

@R_ADE ....there is a function in calculated control called "currentrownumbers". You can use that to generate your ID value.

Though someone has already mentioned how to get the current row number (using the currentRowNumber() function in a Calculated Control), it should be noted that the value will always 'normalize' to match the rows that are present. 

Meaning if we have 4 different rows of information (represented by unique color) 

Row 1

Row 2

Row 3

Row 4

and you were to Delete Row 3. The results would be: 

Row 1

Row 2

Row 3

So, if you had planned on using this method as a way to ensure you can match a Repeating Section Row "ID" to *some* data being generated from it somewhere else, this is not a particularly good method. However, if that does not concern your project, then this is fine. 

I am currently generating "one use only" IDs for one of my Repeating Section Rows, so if you do need to do it that way, we can go down that rabbit hole. As an example, using the above same data sets, if we were to start off with 4 Rows of unique data: 

Row 1 // ID 1

Row 2 // ID 2

Row 3 // ID 3

Row 4 // ID 4

And then deleted Row 3, we'd be left with

Row 1 // ID 1

Row 2 // ID 2

Row 3 // ID 4

See the difference?