diff --git a/src/declarativeimports/core/datamodel.cpp b/src/declarativeimports/core/datamodel.cpp
--- a/src/declarativeimports/core/datamodel.cpp
+++ b/src/declarativeimports/core/datamodel.cpp
@@ -52,13 +52,13 @@
     }
 
     m_roleIds.clear();
-    const QHash<int, QByteArray> rNames = roleNames();
-    m_roleIds.reserve(rNames.count());
-    for (auto i = rNames.constBegin(); i != rNames.constEnd(); ++i) {
+    const QHash<int, QByteArray> roles = sourceModel()->roleNames();
+    m_roleIds.reserve(roles.count());
+    for (auto i = roles.constBegin(); i != roles.constEnd(); ++i) {
         m_roleIds[QString::fromUtf8(i.value())] = i.key();
     }
 
-    setRoleNames(sourceModel()->roleNames());
+    setRoleNames(roles);
     setFilterRole(m_filterRole);
     setSortRole(m_sortRole);
 }
@@ -74,17 +74,20 @@
         return;
     }
 
+    beginResetModel();
+
     if (sourceModel()) {
         disconnect(sourceModel(), SIGNAL(modelReset()), this, SLOT(syncRoleNames()));
     }
 
     QSortFilterProxyModel::setSourceModel(model);
 
     if (model) {
         connect(model, SIGNAL(modelReset()), this, SLOT(syncRoleNames()));
-        syncRoleNames();
     }
 
+    endResetModel();
+
     emit sourceModelChanged(model);
 }
 
@@ -362,8 +365,6 @@
 void DataModel::setItems(const QString &sourceName, const QVariantList &list)
 {
     const int oldLength = m_items.value(sourceName).count();
-    const int delta = list.length() - oldLength;
-    const bool firstRun = m_items.isEmpty();
 
     //At what row number the first item associated to this source starts
     int sourceIndex = 0;
@@ -374,60 +375,38 @@
         }
         sourceIndex += i.value().count();
     }
-    //signal as inserted the rows at the end, all the other rows will signal a dataupdated.
-    //better than a model reset because doesn't cause deletion and re-creation of every list item on a qml ListView, repeaters etc.
-    //the first run it gets reset because otherwise setRoleNames gets broken
-    if (firstRun) {
-        beginResetModel();
-    } else if (delta > 0) {
-        beginInsertRows(QModelIndex(), sourceIndex + oldLength, sourceIndex + list.length() - 1);
-    } else if (delta < 0) {
-        beginRemoveRows(QModelIndex(), sourceIndex + list.length(), sourceIndex + oldLength - 1);
+
+    if (oldLength > 0) {
+        beginRemoveRows(QModelIndex(), sourceIndex, sourceIndex + oldLength - 1);
+        m_items[sourceName].clear();
+        endRemoveRows();
     }
-    //convert to vector, so data() will be O(1)
-    m_items[sourceName] = list.toVector();
+
+    m_roleNames.clear();
 
     if (!list.isEmpty()) {
-        if (list.first().canConvert<QVariantMap>()) {
-            foreach (const QVariant &item, list) {
-                const QVariantMap &vh = item.value<QVariantMap>();
-                QMapIterator<QString, QVariant> it(vh);
-                while (it.hasNext()) {
-                    it.next();
-                    const QString &roleName = it.key();
-                    if (!m_roleIds.contains(roleName)) {
-                        ++m_maxRoleId;
-                        m_roleNames[m_maxRoleId] = roleName.toLatin1();
-                        m_roleIds[roleName] = m_maxRoleId;
-                    }
-                }
-            }
-        } else {
-            foreach (const QVariant &item, list) {
-                const QVariantMap &vh = item.value<QVariantMap>();
-                QMapIterator<QString, QVariant> it(vh);
-                while (it.hasNext()) {
-                    it.next();
-                    const QString &roleName = it.key();
-                    if (!m_roleIds.contains(roleName)) {
-                        ++m_maxRoleId;
-                        m_roleNames[m_maxRoleId] = roleName.toLatin1();
-                        m_roleIds[roleName] = m_maxRoleId;
-                    }
+        beginInsertRows(QModelIndex(), sourceIndex, sourceIndex + list.length() - 1);
+        //convert to vector, so data() will be O(1)
+        m_items[sourceName] = list.toVector();
+        endInsertRows();
+
+        foreach (const QVariant &item, list) {
+            const QVariantMap &vh = item.value<QVariantMap>();
+            QMapIterator<QString, QVariant> it(vh);
+            while (it.hasNext()) {
+                it.next();
+                const QString &roleName = it.key();
+                auto itRole = m_roleIds.find(roleName);
+                if (itRole == m_roleIds.end()) {
+                    itRole = m_roleIds.insert(roleName, ++m_maxRoleId);
                 }
+                m_roleNames[itRole.value()] = roleName.toLatin1();
             }
         }
     }
 
     setRoleNames(m_roleNames);
 
-    if (firstRun) {
-        endResetModel();
-    } else if (delta > 0) {
-        endInsertRows();
-    } else if (delta < 0) {
-        endRemoveRows();
-    }
     emit dataChanged(createIndex(sourceIndex, 0),
                      createIndex(sourceIndex + qMin(list.length(), oldLength), 0));
 }
@@ -462,9 +441,7 @@
             int count = m_items.value(sourceName).count();
             if (count > 0) {
                 beginRemoveRows(QModelIndex(), sourceIndex, sourceIndex + count - 1);
-            }
-            m_items.remove(sourceName);
-            if (count > 0) {
+                m_items.remove(sourceName);
                 endRemoveRows();
             }
         }