As i understand , you want to disable all the fields in the repeating section which the users have already filled-in.
To do so, create a new rule by selecting all the controls to which the rule should apply.
Using Saud's rule above, it will indeed lock things that are already filled out, but has the downfall of instantaneously locking any field that is filled out at all, which creates the assumption that a user will fill things out correctly the first time with no typos!
The following rule that I have made will run at the beginning of each controls creation, and based on the emptiness of the control, will either place a locking css class on it (in the event that it already has a value), or a css class which indicates that it is to be ignored (in the event that it was blank).
This way, you will have the ability to fill in blank or new controls, without locking them, which won't screw up any secondary validation that might be taking place in other rules.
If this solution works and you'd like to learn more about it, I'll come back around and write up a more detailed post as to how it works.
The Code:
(function(sourceContext, callerThis, controlValue) {
var targetFormControlID = callerThis.Name.caller.arguments[2];
var targetControl = sourceContext.find("[formcontrolid='" + targetFormControlID + "'].nf-filler-control");
if (!targetControl.hasClass("ignoreMe") && !targetControl.hasClass("lockMe")) {
if (typeof controlValue !== "number" && typeof controlValue !== "string") {
if (NWF$.type(controlValue) === "array" && controlValue.length > 0) {
controlValue = controlValue.toString();
} else {
controlValue = "";
}
}
if (!controlValue && !targetControl.hasClass("ignoreMe")) {
targetControl.addClass("ignoreMe");
} else {
targetControl.addClass("lockMe");
}
}
return targetControl.hasClass("lockMe");
}(sourceContext, this, {Control:Self}));EDIT (1): It should also be noted that I believe that this code / rule should work in any field anywhere on the form. Not just the ones that reside inside of Repeating Sections. The End.
Edit (2): So I remembered that using the 'callerThis.Control' is unreliable depending on the control you are targeting and the Control(s) responsible for firing the initializing event! Unfortunately the workaround (which can now be seen in the above code as the 'targetFormControlID' variable) is incredibly ugly, and is not compatible with 'use strict' mode, but is the only guaranteed way to always find the correct formcontrolid attribute of the target control in question. Perhaps at some point the Nintex team will consider creating property inside of the context's this that is passed into the rule that contains the correct attribute rather than a variable one.
No matter. I have included the old (bad) code below this change, in the event that someone was interested in what changed. Don't use the below (bad) code!
/* THIS IS THE OLD CODE! DO NOT USE THIS !!!!
(function(sourceContext, callerThis, controlValue) {
var targetControl = sourceContext.find("[formcontrolid='" + callerThis.Control + "'].nf-filler-control");
if (!targetControl.hasClass("ignoreMe") && !targetControl.hasClass("lockMe")) {
if (typeof controlValue !== "number" && typeof controlValue !== "string") {
if (NWF$.type(controlValue) === "array" && controlValue.length > 0) {
controlValue = controlValue.toString();
} else {
controlValue = "";
}
}
if (!controlValue && !targetControl.hasClass("ignoreMe")) {
targetControl.addClass("ignoreMe");
} else {
targetControl.addClass("lockMe");
}
}
return targetControl.hasClass("lockMe");
}(sourceContext, this, {Control
elf}));
*/ 
