ShowMandatory + OnQueryClosePage Check (#147)

* ShowMandatory + OnQueryClosePage Check

* Tighten mandatory-field review guidance

Require explicit ShowMandatory in the good sample, acknowledge that NotBlank marking is unreliable, and limit findings to visible editable controls on paths where users must supply a value.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Copilot-Session: 89dba8c8-6529-4b60-956f-875a59be499d

---------

Co-authored-by: Jesper Schulz-Wedde <jesper.schulzwedde@microsoft.com>
Copilot-Session: 89dba8c8-6529-4b60-956f-875a59be499d

community/knowledge/ui/validate-request-page-input-in-onqueryclosepage.good.al

@@ -0,0 +1,62 @@
+report 50547 "Sample Statement Good"
+{
+    ApplicationArea = All;
+    UsageCategory = ReportsAndAnalysis;
+    Caption = 'Sample Statement Good';
+
+    dataset
+    {
+        dataitem(CustLedgerEntry; "Cust. Ledger Entry")
+        {
+            column(CustomerNo; "Customer No.") { }
+            column(Amount; Amount) { }
+        }
+    }
+
+    requestpage
+    {
+        layout
+        {
+            area(content)
+            {
+                group(Options)
+                {
+                    field(StatementDateField; StatementDate)
+                    {
+                        ApplicationArea = All;
+                        Caption = 'Statement Date';
+                        ToolTip = 'Specifies the date the statement is printed for.';
+                        ShowMandatory = true;
+                    }
+                }
+            }
+        }
+
+        trigger OnQueryClosePage(CloseAction: Action): Boolean
+        begin
+            // Only when the user confirmed the run. Erroring on Cancel or Esc
+            // would trap the user in a page that refuses to close. The error
+            // itself keeps the page open, so the date can be fixed in place.
+            if CloseAction = Action::OK then
+                CheckStatementDate();
+        end;
+    }
+
+    var
+        StatementDate: Date;
+        StatementDateMissingErr: Label 'Enter a statement date.';
+
+    trigger OnPreReport()
+    begin
+        // The same check for runs that have no request page: job queue entries,
+        // Report.Run with the request window suppressed, scheduled and
+        // web-service invocations.
+        CheckStatementDate();
+    end;
+
+    local procedure CheckStatementDate()
+    begin
+        if StatementDate = 0D then
+            Error(StatementDateMissingErr);
+    end;
+}