How to refer to form controls in code without setting the AutoDeclaration property in Dynamics AX?

-
Hello readers,

On a Dynamics AX form, if you want to refer to a particular control in code, the surest way you would take is to set the AutoDeclaration property to Yes. This will let you refer the control in code. There is nothing wrong with this approach and it is quite common in standard Dynamics AX codebase.

But in some cases, it is preferred not to use this approach. So what is this case?

Consider a scenario where you are customizing a standard form. You want to disable a particular field based on a field value.

To achieve this,

- You will set the AutoDeclaration property of the control to Yes
- In the active method of the datasource, you will disable the control based on a condition.

Now, the active() method's modification can be easily seen in the AOT but the change in property isn't readily noticed unless you perform a layer compare.

Normally, in cuztomization it is a best practise to add customization tags to show what part is customized code and what is standard. But there is no way we can add a customization tag to properties that have changed.

Coming back to the main topic, so how do we refer to a control in code without setting AutoDeclaration to Yes.

The answer lies in the control() method of formRun class.

So let us say my control name is AccountNum and form name is Address. So my code will look something like this,
element.control(control::AccountNum).enabled(false);
The control:: enum enumerates all controls on the given form. The only problem is that you wont get an intellisense on the control names. Just type it and then compile.

In Dynamics AX 2012, we have a new method controlId() on the formRun class. This in conjunction with the new intrinsic method formControlStr() can be used to get the control id.

So the above line of code will be written as following in Dynamics AX 2012
// This is the line in Dynamics AX 2009
element.control(control::AccountNum).enabled(false);

// And this is how it should be written in Dynamics AX 2012
element.control(element.controlId(formControlStr(Address, AccountNum))).enabled(false);
Although, there is nothing wrong in setting AutoDeclaration to Yes for customization, it is a cleaner approach to just reference the control in code using the above method.

I hope this post was helpful. Please leave your comments here.

Thats all for today. Do check back soon as we have lots of new things coming up.

Comments

Jan B. Kjeldsen said…
While referring to controls through the use of element.control is possible, the more usual thing is to refer to the datasource field.

This has the added advantage that it will work for controls added by the user, and when the field is added twice, say in the grid and in a tab.

The syntax:
address_ds.object(fieldNum(Address,AccountNum)).enabled(false);
22 August 2011 at 03:27
Zubair Ahmed said…
Hi Jan,

Thanks for pointing this out. It is preferrable to directly act on the datasource field if it is available.

For other controls which are not bound to a datasource, we can use the element.control approach.
22 August 2011 at 07:33
Post a Comment

Popular posts from this blog

How to add empty ranges in query

-
In Dynamics AX programming, a common mistake I have seen when it comes to query ranges is passing an empty string value to the range. The developer here is expecting it to show all the records where the range field is empty. Instead, what we get is all records without the range being applied. As baffling as it may seems, it is easily explainable. The query engine in Dynamics AX, will not add a range if you don’t specify a value or if you specify an empty string because an empty string is treated as no value. So the following code will result in this SQL statement, query = new Query(); qbds = query.addDataSource(tableNum(ProjTable)); qbr = qbds.addRange(fieldNum(ProjTable, Name)); qbr.value(''); Select first fast * from ProjTable; But what was expected was something like, Select first fast * from ProjTable where Name == ''; So to work around this issue, use the SysQuery::valueEmptyString() static method which parses the empty strings correctly so that it...
Read more

The field with ID '0' does not exist in table - Cause and resolution.

-
Image
Hello readers, In Dynamics AX coding, you should have come across this error sometime - The field with ID '0' does not exist in table 'SomeTable' So what causes this error and what is the possible resolution to it? Well, the most likely cause for this error is a missing mapping in a table map. Let us look at an example. I've a simple Map named CustVendAccount with one Account field. I've created two mappings - one with CustTable's AccountNum field and for the otehr mapping, I just specify VendTable but no field. This is how my map looks like, Now, I've a simple job which just passes either CustTable or VendTable as an argument and then we print the Account field in the map. static void CustVendAccountMap(Args _args) { CustTable custTable; VendTable vendTable; void readMap(CustVendAccount _custVendAccount) { info(strFmt("Value from table %1 is %2",tableId2name(_custVendAccount.TableId), _custV...
Read more

Get selected records in Dynamics AX 2012

-
Image
In my earlier post, we discussed how we can retrieve all selected records on a list page. You can read that post here . Retrieving all selected records from a caller form is very easy. The code for this can be found in a number of places in standard Dynamics AX codebase. The general approach is to use the dataSource.getFirst(1) statement to get the first selected record and loop through the remaining using dataSource.getNext() . In Dynamics AX 2009, a new class was introduced for this purpose. This was the MultiSelectionHelper class. In Dynamics AX 2012, another new class has been introduced to retrieve the selected records. This is the MultiSelectionContext class. The MultiSelectionHelper class is an application class. It presents two constrcutors. The standard constructor method just creates a new instance of the MultiSelectionHelper class. When this construct is used, you will have to explicitly set the dataSource to be used for fethcing selected records. This can be done...
Read more