Extracting data from excel sheet to CDT

AFIK, It is good approach to design a process model for this type of Scnerios, This will reduce overload on the form(SAIL UI) when the Excel sheet contains data that will take noticeable time.
In future the uploads increased also this can be continued instead of handling in the UI.
Lets see what other Practitioners suggest

Possible approach:
1. Get the data in the excel into a CDT variable - use the plugin for this. the plugin should contain a expression function for it, so that it could be used on the SAIL form
2. Then validate it on the SAIL form itself.
3. Enable/Disable the submit button based on the validation.

A problem here will be that - since you want to validate before the form is submitted, the excel document will not actually have been created in Appian system - hence permanent docId would not have been generated. So, the plugin function may not work..
The Excel tools plugin (forum.appian.com/.../summary) has a function to read data from Excel, but you need to check what inputs it needs.
It is likely that it needs a docId, in that case the docId needs to be valid one (and for that the document should be actually uploaded in Appian).
If that is the case, then you need to think of some other approach

Thanks a lot for the information.

@chetany it seems good if we have a document that is already present in appian. we have implemented something like, user has uploaded the excel document on clicking on Upload button submit the form, read the data from the Excel and put in a pv(capture an error if any)loop it back to the same Task and display the error or success message.

@chandrasekharg , yes , definitely uploading the document and looping back to the same task would be a good approach.