Delphi 7 : Lookup Field?

Hi Experts,

I have an TDBGrid and would like the use to be able to pick from a dropdown in the list.
For example:

ColorCode VARCHAR(10)
Description VARCHAR(100)

VehicleID INT PK
RegNumber VARCHAR(20)

When inserting a new row in the DBGrid for Table2, I would like to user to be able to select from dropdown in grid from all the available colorcodes and after selecting the ColorID should be saved in this table.

I managed to get what I am looking by means of creating a new lookup field on my ADOTable Component for Table2. But when inserting a new row I receive the following error:

"raised exception class EOleException with message 'An unkown error has occurred.' Process stopped...."

Please advise.
Who is Participating?
RickJConnect With a Mentor Commented:
Hello marius0188,
I downloaded and tried your example and it works fine for me.
Guessing it may be something that was fixed with the delphi 7 service update 1. Do you have that installed?
I think you need to be a registered user to download it.

developmentguruConnect With a Mentor PresidentCommented:
We would need to see your code for starters.  There is nothing wrong with how you are handling the lookup field, that in itself should not cause an error.  I suspect that something was missing in how it was set up.  Can you show us a simplified example?
Marius0188Author Commented:
Here is a screenshot of my setup:

I use a normal TDBGrid and TADOTable components.

The 14th Annual Expert Award Winners

The results are in! Meet the top members of our 2017 Expert Awards. Congratulations to all who qualified!

JohnjcesConnect With a Mentor Commented:
I am confuised, but that is pretty normal for me...

Are you storing in your dataset the color as a string name such as clRed, or clBlack or are you storing the actual color identifier, which will be a hex value such as $000000FF, (decimal 255 which is clRed) .

ColorID as an Int sounds OK if you are storing the color value, but I do not know about what you are storing in ColorCode and if that is like clRed.

Not sure if it is a table/database issue or some other code part failing when getting the color.

A code snippet or two will really be helpful as developmentguru has suggested. A picture can be worth a thousand words, but...

Marius0188Author Commented:
I have build a demo app using Firebird database and Interbase components.
I have created a lookup table exactly as I have done with the ADO table components and it is WORKING here.

I guess there is something else about the TADOTable component.
Let me see if I can provide you with a demo.

Marius0188Author Commented:
Ok I have produced a demo for you:

Just connect both TIBDatabase & TADOConnection components to the databasis that is in a subfolder.
1 x Firebird DB

The firebird is working 100%.
The SQL db is giving me that nasty exception.

Thanks in advance!

Marius0188Author Commented:
It looks like a bug in ADO.

Is there any work arounds?
Where can I get the latest Delphi 7 updates?

Marius0188Author Commented:
Can one connect to SQL 2005 db without using ADO components?
Is there any other good alternative components or methods one can try?
Marius0188Author Commented:
Yes I do have that update.
But if I remember correctly, when installing that update it prompt to notify me about missing files where after I just clicked ignore. Maybe it has something to do with that.

Mmmmh, I wonder if I can just update the ADO dcu's etc by getting them from you.
Will that not work?
Much cleaner to get your intall to work correctly, but worth a shot I guess.
Would back up before attempting.
Here you go.
Marius0188Author Commented:
Nope, still not working.

Are you also using Delphi 7 Enterprise?
Delphi 7 pro. I would have thought the ado stuff would have been the same. But I could be wrong.
Not sure how else I can help you...
Marius0188Author Commented:
You don't think it might be the TDBGrid component?
Maybe you must sent me your source and let me try that.

I still think getting your install correct would be a better way to go. But again,
Here you go.
Marius0188Author Commented:
Yip, after this one I will go for re-install and then apply that 7.1 update.
But need a quick fix because installing all my components from start takes 1-2 days.

Marius0188Author Commented:
Ok but another thing is:
It is only in the compiler (IDE) that I get the exception EOleException.

When running outside the IDE no problem.
Should I still be worried?
Marius0188Author Commented:
Ok I will accept that this might be an installation problem.
Have not tested yet but will try to re-install as soon as I have time available.

Lets split the points....

Thanks to all!
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.