This article describes events terminology with examples in X++.
You can use the event design pattern to make your code more modular and reusable. The term event is a metaphor that explains how delegates are used. When something important occurs during a program run, other modules might have to process the occurrence. These important occurrences are known as events.
Pre / Post form level event handlers
You need to create a new class to write the form Pre / Post event handler methods.
class PurchTable_Form_EventHandler
{
[PreHandlerFor(formStr(PurchTable), formMethodStr(PurchTable, init))]
public static void PurchTable_Pre_init(XppPrePostArgs args)
{
FormRun formRun = args.getThis();
FormDesign formDesign = formRun.design();
if(formRun.args().menuItemName() == menuItemDisplayStr(PurchTableListPage))
{
// Your code
}
else if (formRun.args().menuItemName() == menuItemDisplayStr(PurchTable))
{
// Your code
}
}
[PostHandlerFor(formStr(PurchTable), formMethodStr(PurchTable, init))]
public static void PurchTable_Post_init(XppPrePostArgs args)
{
FormRun formRun = args.getThis();
FormDesign formDesign = formRun.design();
if(formRun.args().menuItemName() == menuItemDisplayStr(PurchTableListPage))
{
FormControl POState;
POState = formDesign.controlName(formControlStr(PurchTable, PurchTable_State));
POState.visible(false);
Info("MenuItemName: PurchTableListPage");
}
else if (formRun.args().menuItemName() == menuItemDisplayStr(PurchTable))
{
Info("MenuItemName: PurchTable");
}
}
}Form level event handlers – same will apply for others standard form level events like (OnActivated, OnClosing, etc.)
class PurchTable_Form_EventHandler
{
[FormEventHandler(formStr(PurchTable), FormEventType::Initialized)]
public static void PurchTable_OnInitialized(xFormRun sender, FormEventArgs e)
{
FormRun formRun = sender as FormRun;
FormDesign formDesign = formRun.design();
FormDataSource purchTable_ds = formRun.dataSource("PurchTable");
PurchTable purchTable = purchTable_ds.cursor();
FormControl customFields = formDesign.controlName("POHeaderCustomFields");
customFields.visible(false);
}
}Form DataSource level event handlers – same will apply for others standard form DataSource level events like (OnInitialized, OnActivated, OnDeleted, etc.)
class PurchTable_Form_EventHandler
{
[FormDataSourceEventHandler(formDataSourceStr(PurchTable, PurchTable), FormDataSourceEventType::InitValue)]
public static void PurchTable_OnInitValue(FormDataSource sender, FormDataSourceEventArgs e)
{
FormRun formRun;
FormDataSource purchTable_ds;
PurchTable purchTable;
formRun = sender.formRun();
purchTable_ds = formRun.dataSource(formDataSourceStr(PurchTable, PurchTable)) as FormDataSource;
purchTable = purchLine_ds.cursor();
if(purchTable.CustAccount)
purchTable.CustName = CustTable::find(purchTable.CustAccount).name();
}
}Form data field level event handlers – same will apply for others data field level events like (OnValidated, OnValidating, etc.)
class PurchTable_Form_EventHandler
{
//[FormDataFieldEventHandler(formDataFieldStr(FormName, DataSource, DSDataField), FormDataFieldEventType::Modified)]
[FormDataFieldEventHandler(formDataFieldStr(PurchTable, PurchTable, CustomBaseEnum), FormDataFieldEventType::Modified)]
public static void CustomBaseEnum_OnModified(FormDataObject sender, FormDataFieldEventArgs e)
{
FormRun formRun = sender.datasource().formRun();
FormDesign formDesign = formRun.design();
//FormDataSource purchTable_ds = formRun.dataSource(FormDataSourceStr(FormName, DataSource)) as FormDataSource;
//FormDataSource purchTable_ds = formRun.dataSource("DataSource")); // We can also pass direct dataSource name as string.
FormDataSource purchTable_ds = formRun.dataSource(FormDataSourceStr(PurchTable, PurchTable)) as FormDataSource;
//FormRun formRun_1 = purchTable_ds.formRun(); // we can also get the formRun from dataSource
PurchTable purchTable = purchTable_ds.cursor();
FormControl customField = formDesign.controlName("PurchTable_CustomField");
CustomField.allowEdit(false);
if(purchTable.CustomBaseEnum == CustomBaseEnum::Value)
purchTable.CustomField = "Value";
else
purchTable.CustomField = "Value_1";
}
}Form control level event handlers – same will apply for others control level events like (OnValidated, OnSelectionChanged, OnLookup, etc.)
class PurchTable_Form_EventHandler
{
//[FormDataFieldEventHandler(formDataFieldStr(FormName, DataSource, DSDataField), FormDataFieldEventType::Modified)]
[FormDataFieldEventHandler(formDataFieldStr(PurchTable, PurchTable, CustomBaseEnum), FormDataFieldEventType::Modified)]
public static void CustomBaseEnum_OnModified(FormDataObject sender, FormDataFieldEventArgs e)
{
FormRun formRun = sender.datasource().formRun();
FormDesign formDesign = formRun.design();
//FormDataSource purchTable_ds = formRun.dataSource(FormDataSourceStr(FormName, DataSource)) as FormDataSource;
//FormDataSource purchTable_ds = formRun.dataSource("DataSource")); // We can also pass direct dataSource name as string.
FormDataSource purchTable_ds = formRun.dataSource(FormDataSourceStr(PurchTable, PurchTable)) as FormDataSource;
//FormRun formRun_1 = purchTable_ds.formRun(); // we can also get the formRun from dataSource
PurchTable purchTable = purchTable_ds.cursor();
FormControl customField = formDesign.controlName("PurchTable_CustomField");
CustomField.allowEdit(false);
if(purchTable.CustomBaseEnum == CustomBaseEnum::Value)
purchTable.CustomField = "Value";
else
purchTable.CustomField = "Value_1";
}
}