Alpha DevCon 2018
Results 1 to 7 of 7

Thread: UX LIST control Custom Data Source xBasic called by Alpha at design time fails.

  1. #1
    Member
    Real Name
    Rich Fulham
    Join Date
    May 2011
    Location
    Portland, OR
    Posts
    815

    Post UX LIST control Custom Data Source xBasic called by Alpha at design time fails.

    Can someone tell me the proper way to code an XBasic function specifically for the source of a LIST control on a UX?

    I have looked at the three on-screen sample snippets and none of them address the issue I am having:

    The Alpha UX Designer insists on calling the xBasic function to get a list of fields that will be used and since session variables and/or UX arguments have not been initialized, the code fails.

    What is the recommended way of knowing when the function is being called simply to get a list of data fields for the designer?

  2. #2
    "Certified" Alphaholic
    Real Name
    David Kates
    Join Date
    Apr 2008
    Location
    Unionville, ON
    Posts
    6,729

    Default Re: UX LIST control Custom Data Source xBasic called by Alpha at design time fails.

    Execute a simpler version of your XBasic List code in order to design your List. Since you're using session vars / arguments in your sql execute statement, then set those arguments locally... while designing your List. Your first goal is to get an XBasic function to return rows, formatted for the List. Then you can start setting up incoming variables and arguments which will exist before your List gets rendered.

    So, while testing and setting up, initialize everything you need in the XBasic List code.

  3. #3
    Member
    Real Name
    Rich Fulham
    Join Date
    May 2011
    Location
    Portland, OR
    Posts
    815

    Default Re: UX LIST control Custom Data Source xBasic called by Alpha at design time fails.

    David, my problem came up well after my UX and LIST had been developed and moved into production. So, putting in a simpler version of the code just to do a little bit of debugging was something I did not want to do, if it could be avoided. My UX was working perfectly with my development database and with my testing data on the production server. But it would not work outside of those two systems.

    The solution I reluctantly adopted was to supply default values for all of the Arguments in the UX. Default values keep the Alpha LIST designer happy because it can retrieve sample data whenever it wants.

    Maybe Alpha assumes developers will supply default values when defining Arguments. But, I have been very reluctant to do this because I have been afraid those default values might end up getting used by Alpha in a production environment. It would be really bad if my development default values appeared in a production system. The user could end up seeing data that made absolutely no sense, or worse yet, in this multi-tenant app, they might see some other tenant's data!

    The problem that prompted this post in this first place turned out to be an issue where Alpha was using a primary key value from my testing database and not the intended primary key value from the production database! This was not because of Arguments, but I think the point is the same - for some inexplicable reason a value that I had used during testing got persisted into the component for production! I never found where this value was coming from in the UX Designer. However, I did see a line of code near the very bottom of XBasic source of the component that was declaring my problem variable:

    DIM tmpl.rtc.cpModel_SysID as C = "2"

    I had XBasic code to declare and then initialize the variable in two separate lines of code in a server-side event which I had hoped would make the variable available to a custom field in the LIST. I had thought my initialize code was working, but it hadn't been. No matter what, this variable always had a value of "2" when I went to use it. I didn't discover this until I tried to run the system outside of my two testing databases.

  4. #4
    "Certified" Alphaholic
    Real Name
    David Kates
    Join Date
    Apr 2008
    Location
    Unionville, ON
    Posts
    6,729

    Default Re: UX LIST control Custom Data Source xBasic called by Alpha at design time fails.

    I don't like to supply default values either... handy at times... but risky.

    For the XBasic List function, I would just hard code whatever variables I need for testing... that's all... that's what I meant by a simpler version. Allow the XBasic code to work on it's own, running in Live or Working Preview for debugging. Hard code the session vars which can then simply be commented out when testing moves to the List. There's no other way to test the XBasic by itself.

  5. #5
    "Certified" Alphaholic peteconway's Avatar
    Real Name
    Peter Conway
    Join Date
    Oct 2005
    Location
    Melbourne, Australia
    Posts
    2,478

    Default Re: UX LIST control Custom Data Source xBasic called by Alpha at design time fails.

    I always used a copy of the latest component to make the changes (kept it away from live) - it was painful but pasting in the temporary values is the only way I could figure out to use it as well - it's a difficult problem.
    Insanity: doing the same thing over and over again and expecting different results.
    Albert Einstein, (attributed)
    US (German-born) physicist (1879 - 1955)

  6. #6
    Member
    Real Name
    Rich Fulham
    Join Date
    May 2011
    Location
    Portland, OR
    Posts
    815

    Default Re: UX LIST control Custom Data Source xBasic called by Alpha at design time fails.

    I think it would be nice if the "e.getDataMode" variable that gets passed into the custom Xbasic source procedure for populating a list had at least one more value, like "getColNames" that the designer (or even the server for that matter) would use when it needed a list of column names. I suppose Alpha may want sample data or data types, if so maybe it could pass in a different value like, "getSampleData".

    There may also be one other complication: the use of "Custom Control" fields in a LIST. My LIST uses two Custom Control fields and one of those needs a value that happens to remain constant for the given set of records that are being displayed by the LIST. That semi-constant piece of data is not very convenient or practical to gather from SQL and place into all the records in the LIST.

  7. #7
    "Certified" Alphaholic
    Real Name
    David Kates
    Join Date
    Apr 2008
    Location
    Unionville, ON
    Posts
    6,729

    Default Re: UX LIST control Custom Data Source xBasic called by Alpha at design time fails.

    Have to disagree. It's a process of developments step just like anything else. If a component is expecting data from XBasic, you build and test the XBasic process on it's own first... always. Otherwise, you never know which piece is not working. Once the function is working independently, you work it into the List. Also, I wouldn't think adding a constant into the SQL data would be a big deal. It's all tough because it's all new to you... but this is advanced stuff... so... it takes a bit of time to become familiar with it.

Similar Threads

  1. List builder xbasic custom data source using http_get
    By jmsilva in forum Mobile & Browser Applications
    Replies: 5
    Last Post: 03-03-2016, 10:41 PM
  2. UX List's custom Control (column) - to access UX control in xbasic/server
    By Mkpatil in forum Mobile & Browser Applications
    Replies: 11
    Last Post: 11-17-2015, 11:58 PM
  3. List w/ Custom Data Source - SQL Query with Nested JSON Arrays
    By TheSmitchell in forum Mobile & Browser Applications
    Replies: 6
    Last Post: 07-03-2015, 07:48 AM
  4. List control with custom data source and parent list
    By sjackson@drake in forum Mobile & Browser Applications
    Replies: 1
    Last Post: 07-01-2015, 09:26 PM
  5. Populate List through custom data source - Help
    By mikeallenbrown in forum Mobile & Browser Applications
    Replies: 4
    Last Post: 05-27-2015, 10:08 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •