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Can I override a table event handler if table itself has extension?

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I created a extension (CustTable.Extension) to table "CustTable" to add more fields.

Then I would like to override onModifiedField event handler so I created a class "CustTable_Extension" and copy/paste the onModifiedField event handler and modified to the following:

[ExtensionOf(tableStr(CustTable))]
final class CustTable_Extension
{

/// <summary>
///
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
[DataEventHandler(tableStr(CustTable), DataEventType::ModifiedField)]
public static void CustTable_onModifiedField(Common sender, DataEventArgs e)
{
ModifyFieldEventArgs event = e as DataEventArgs;
CustTable custTable = sender as CustTable;
FieldId fieldId = event.parmFieldId();

switch(fieldId)
{
case fieldNum(CustTable, ContactPersonId):

break;

default:
break;
}

}

It's simple customization for event handler but somehow this piece of code is never executed even when I modified "ContactPersonId". I am wondering whether or not create customized event handler for the table when there is another table extension to add new fields is NOT supported? If so, what could be workaround?

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Sukrut Parab 71,735 Moderator on at

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Hi Yvonne,

You should not add event handlers to extension class . below link explains it well why

daxmusings.codecrib.com/.../accidental-code-extensions.html

You can just implement your handler in a normal class with proper naming convention . for example MyCusttableHandler class

Now for your another question , you can use COC on table modified field method instead of using event handler. That would be the first place i would look at , if you want something on modified event of the field.

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Community Member on at

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Hi Sukrut,

Does this mean override table event handler only work when there is no other table extension at all (no table extension on the table level for adding fields or table extension on class level to override methods)?

Thanks,

Lin-Lin

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Community Member on at

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It seems writing COC on "modifiedField" method does not work either. The code compiled code never get to the breakpoint set in there even the field is modified. It works for the table without any extension to add fields, so are these the current limitations of extension?

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Sukrut Parab 71,735 Moderator on at

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I am not aware of any limitation . If you are sure , you are writing code at correct place and executing correct process which will trigger that code then breakpoint should hit.

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Khushhal Garg 1,514 on at

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I am using OnModifiedField eventhandler and it is working fine. I have created public class and have added following method and it is working fine.

[DataEventHandler(tableStr(VendTable), DataEventType::ModifiedField)]

public static void VendTable_onModifiedField(Common sender, DataEventArgs e)

{

VendTable record = sender as VendTable;

ModifyFieldEventArgs args = e as ModifyFieldEventArgs;

FieldId fieldId = args.parmFieldId();

I am seeing you are using

ModifyFieldEventArgs event = e as DataEventArgs;

instead of

ModifyFieldEventArgs args = e as ModifyFieldEventArgs;

that might be the issue. Can you change your code also to

ModifyFieldEventArgs args = e as ModifyFieldEventArgs;

and move event handler to public class from final class?

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Blue Wang Microsoft Employee on at

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Hi Yvonne,

I don't think it's a good way to use event handlers in extensions.

Of course, you can achieve your needs, and this is the previous method.

You can refer to this thread:

[View:https://community.dynamics.com/ax/f/microsoft-dynamics-ax-forum/217518/using-pre-post-event-handlers-on-modifiedfield-method-of-a-table-in-case-of-customization:750:50]

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nmaenpaa 101,166 Moderator on at

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There can be many extensions for the same object, and many event handlers for the same event.

As pointed out above, it seems that your issue might happen because you are using incorrect DataEventArgs type instead of ModifyFieldEventArgs.

You should not add event handlers to extension classes. Instead you should create separate event handler classes that don't extend any other class.

By the way, you should not name your extensions like CustTable.Extension (or classes like CustTable_Extension), instead you should include your prefix in the name. Otherwise you might have issues / conflicts in the future when applying Microsoft updates.

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I found out the issue is ContactPersonId on CustTable cannot trigger onModifiedField event as the field is being set by editContactPerson() method on the data source. For any other fields that are directly mapped to CustTable fields will not have problem.

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