# Formevents
Custom code, attatched to an entity, getting called at different times
# Understanding formevents
## Execution order
# Creating the codeunit
1. Make sure that **p2eShared.jar** is included in the project
2. Create a new class that extends
```
com.tsnocode.codeunit.CodeunitFormevents
```
# LIST level event hooks
```java
public String appendListPageHead() { return ""; }
public String appendListPageFoot() { return ""; }
```
```java
public void beforeSelectList() throws Exception {}
public void beforeRenderList() throws Exception {}
```
#### LIST execution order
1. **beforeSelectList**
2. Gather form data from database
1. dataFilterActive > dataFilterHandler
2. listFilterActive > listFilterHandler
3. **beforeRenderList**
4. Return list to user
# ITEM level event hooks
```java
public String appendItemPageHead() { return ""; }
public String appendItemPageFoot() { return ""; }
```
```java
public void beforeSelectItem() throws Exception {}
public void beforeChangeItem() throws Exception {}
public void beforeUpdateItem() throws Exception {}
public void beforeRenderItem() throws Exception {}
public void afterUpdateItem() throws Exception {}
public boolean afterUpdateRedirectActive() { return false; }
public String afterUpdateRedirectContent() { return null; }
```
#### ITEM execution order: viewing data
1. **beforeSelectItem**
2. Gather form data from database
- dataFilterActive > dataFilterHandler
- itemFilterActive > itemFilterHandler
3. **beforeRenderItem**
4. Return form to user
#### ITEM execution order: posting data
1. **beforeSelectItem**
2. Gather form data from database
3. **beforeChangeItem**
4. Update field values
5. **beforeUpdateItem**
6. Write changes to database
7. **afterUpdateItem**
8. if NO OTHER ACTION:
- **afterUpdateRedirectActive**
- if TRUE
- **afterUpdateRedirectContent**
9. Return content to user
# FILTER event hooks
Filters will help you build customized permission schemes. They are called for **both** LIST and ITEM commands.
```java
@Override
protected boolean dataFilterActive() {
return true;
}
@Override
protected void dataFilterHandler(StringBuilder sql) {
sql.append(" AND something");
}
```
In some cases you only want the filter to trigger for **either** LIST or ITEM commands
```java
itemFilterActive() {}
itemFilterHandler(StringBuilder sql) { return sql; }
listFilterActive() {}
listFilterHandler(StringBuilder sql) { return sql; }
```
### Examples
The xxxFilterActive tells if the filter is active
```java
boolean dataFilterActive() { return !s.isAdministor(); }
```
The xxxFilterHandler modifies the SQL used to fetch data
```java
void dataFilterHandler(StringBuilder sql) { sql.append(" AND CATEGORY NOT IN (123,456,789)"); }
```
# Event firing details
#### Event firing global
The following events are ALLWAYS fired
- beforeSelectList
- beforeSelectItem
- beforeChangeItem
- beforeUpdateItem
- afterUpdateItem
#### Event firing in UI (reserved for normal users)
The following events will NOT be fired during imports etc.
- appendListPageHead
- appendListPageFoot
- beforeRenderList
- appendItemPageHead
- appendItemPageFoot
- beforeRenderItem
#### Event firing in UI depending on user actions
The following events are SOMETIMES be fired for normal users depending on navigation
- afterUpdateRedirectActive
- Not executed in SUBFORM mode
- Not executed in during imports etc.
- afterUpdateRedirectContent
- Depends on a TRUE result from afterUpdateRedirectActive()