Added classes to manage simple tabular data of known structure using a

popup containing a wxGrid object.

BasePicker : Abstract class adding a popup to wxPickerBase  styled with
a wxTextCtrl.
BaseGridPicker : Abstract class adding a wxGrid in the popup.

JsonGridPickerCtrl : UI control storing the tabular data in a JSON
array.
LBoundJsonGridPicker : connect JsonGridPicker to database.
LGridJsonCellEditor : use LBoundJsonGridPicker in other wxGrid objects.
LGridJsonCellRenderer : render cell JSON data.

XmlGridPickerCtrl : UI control storing the tabular data in as XML
document.
LBoundXmlGridPicker : connect XmlGridPicker to database.
LGridXmlCellEditor : grid editor for LBoundXmlGridPicker.
LGridXmlCellRenderer : grid renderer for LBoundXmlGridPicker.

JsonHelper and XmlHelper : for applications to quickly get intent value
from database data..

The structure of managed tabular data :

Column 1 : Intent - this is what we want to store/edit. This can be
telephone numbers, email addresses, instant messaging addresses...
any single line piece of information that can exist many times for one
entity (person, company...).
Column 2 : Type - A short description of the intent : 'Home, Work,
Mobile, Fax, Other...'. It is displayed in a non editable wxComboBox.
Column 3 : Preferred - One line of data can be selected as the preferred
one. It is not mandatory, but it must be a single choice.
Column 4 : Notes - single line notes.

Adjust sql scripts and L7.dox.
Applied ANSI formatting style to all files.

Other changes :

Work around a nasty misbehavior.
Grid columns edited by a translated combobox expect full string
data as cell values. LResultSet::BEData() will report these mapped strings,
instead of database real data. LBoundComboBox::IsDirty() will always be
true even if the editor is unchanged once created.
Simplest workaround : disconnect m_BoundComboBox if unchanged.

LGridTextEditor::ProvideFormEditor() : set the form editor's value
explicitely.; wxTextCtrl does not interpret data it receives

LBoundControl::SetNull must be void.

LBoundGrid : Unbind:: instructions should limit to the widget's id, like Bind::

LConnection::GetReturnedKeys should return NULL.
LConnection::SetData should return void.

Notes : wxJSON must be configured with the same prefix as wxWidgets,
here /usr/local/{wxWidgets,wxWidgets-Release}.

L7/special/XmlHelper.cpp

@@ -0,0 +1,75 @@
+/* 
+ * File:   XmlHelper.cpp
+ * Author: SET - nmset@netcourrier.com
+ * License : LGPL version 2.1
+ * Copyright SET, M. D. - © 2014
+ * 
+ * Created on December 15, 2019, 4:13 PM
+ */
+
+#include "XmlHelper.h"
+#include <wx/sstream.h>
+
+XmlHelper::XmlHelper()
+{
+}
+
+XmlHelper::~XmlHelper()
+{
+}
+
+// if doc is declared with local scope, root elements are empty in caller
+
+wxXmlNode* XmlHelper::ValidateXmlValue(wxXmlDocument& doc, const wxString& value)
+{
+    // Avoid 'XML parsing error' message box.
+    wxLogNull lognull;
+    wxStringInputStream sis(value);
+    bool res = doc.Load(sis);
+    if (!res)
+    {
+        wxASSERT_MSG(res == true, _T("Can't load XML data.\n") + value);
+        return NULL;
+    }
+    wxXmlNode * root = doc.GetRoot();
+    if (root->GetName() != XML_ROOT_NAME)
+    {
+        wxASSERT_MSG(root->GetName() != XML_ROOT_NAME, _T("Bad XML data.\n") + value);
+        return NULL;
+    }
+    // Check all rows and attributes
+    wxXmlNode * row = root->GetChildren();
+    while (row)
+    {
+        if (row->GetName() != XML_ROW_NAME
+                || !row->HasAttribute(XML_ATTR_TYPE)
+                || !row->HasAttribute(XML_ATTR_PREF)
+                || !row->HasAttribute(XML_ATTR_NOTES)
+                || row->GetNodeContent().IsEmpty())
+        {
+            wxASSERT_MSG(root->GetName() != XML_ROOT_NAME, _T("Unexpected XML data.\n") + value);
+            return NULL;
+        }
+        row = row->GetNext();
+    }
+    return root;
+}
+
+wxString XmlHelper::GetIntent(const wxString& xmlData)
+{
+    if (xmlData.IsEmpty())
+        return wxEmptyString;
+    wxXmlDocument doc;
+    wxXmlNode * root = ValidateXmlValue(doc, xmlData);
+    if (root == NULL)
+        return wxEmptyString;
+    wxXmlNode * row = root->GetChildren();
+    while (row)
+    {
+        const wxString pref = row->GetAttribute(XML_ATTR_PREF);
+        if (!pref.IsEmpty() && pref != _T("0"))
+            return row->GetNodeContent();
+        row = row->GetNext();
+    }
+    return wxEmptyString;
+}