Can you deploy single aspx.cs file using Visual Studio Web Publish to Azure Web App (Azure runtime issue)

I’ve noticed that although I’m able to successfully deploy my web app (ASP.NET) to Azure using web publish in Visual Studio. I’m also able to successfully deploy individual files to the server directory, by right clicking on the file in the solution explorer and clicking publish.

DetailsView Error: “Must declare the scalar value…”

I am attempting to use DetailsView in ASP.NET and c# to show a list of students that are associated with the logged-in user (which will be a teacher after they login to the system). I have been trying to using scalar values so my program can be more dynamic once a teacher types in the last name of the student they want to find in the system. I’m not sure why I am getting the error
must declare the scalar value
when I (think I) am declaring it on the ASP side of my code. I’ve been searching for solutions to this for a couple of hours now so any and all help would be greatly appreciated.

Multiline textbox value split using javascript in Asp.Net C#

Asp.Net C# Multiline textbox(textbox1) value split after 35 charaters of address & add to textbox(textbox2 – Singleline) again split next 35 charaters & add to textbox(textbox3 – Singleline) again split next 35 charaters & add to textbox(textbox4 – Singleline) again split next 35 charaters & add to textbox(textbox5 – Singleline).
Note: While Splitting value after 35 characters make sure if a word is incomplete then add that word in next line like(…31 address – here at add position of address is 35 characters so it’ll get slipt & gets add to new textbox, but I want that word address in new textbox & from their it should count to 35 charaters like so on.)