diff --git a/demo/src/Bindings.cpp b/demo/src/Bindings.cpp
index 47aa898..ff25bbc 100644
--- a/demo/src/Bindings.cpp
+++ b/demo/src/Bindings.cpp
@@ -816,6 +816,9 @@ QVariant TimeSeries::cos(int row) const
 bool TimeSeries::setCos(int row, const QVariant& value)
 {
     bool set = false;
+    if (!value.canConvert(qMetaTypeId<float>())) {
+        return false;
+    }
     set = time_series_set_data_cos(m_d, row, value.value<float>());
     if (set) {
         QModelIndex index = createIndex(row, 0, row);
@@ -834,6 +837,9 @@ QVariant TimeSeries::sin(int row) const
 bool TimeSeries::setSin(int row, const QVariant& value)
 {
     bool set = false;
+    if (!value.canConvert(qMetaTypeId<float>())) {
+        return false;
+    }
     set = time_series_set_data_sin(m_d, row, value.value<float>());
     if (set) {
         QModelIndex index = createIndex(row, 0, row);
@@ -852,6 +858,9 @@ QVariant TimeSeries::time(int row) const
 bool TimeSeries::setTime(int row, const QVariant& value)
 {
     bool set = false;
+    if (!value.canConvert(qMetaTypeId<float>())) {
+        return false;
+    }
     set = time_series_set_data_time(m_d, row, value.value<float>());
     if (set) {
         QModelIndex index = createIndex(row, 0, row);
diff --git a/src/cpp.cpp b/src/cpp.cpp
index 352e3de..faf8d30 100644
--- a/src/cpp.cpp
+++ b/src/cpp.cpp
@@ -173,6 +173,7 @@ void writeModelGetterSetter(QTextStream& cpp, const QString& index,
                 .arg(lcname, snakeCase(ip.name), idx) << endl;
         cpp << "    } else\n";
     }
+    cpp << QString("    if (!value.canConvert(qMetaTypeId<%1>())) {\n        return false;\n    }\n").arg(ip.type.name);
     QString val = QString("value.value<%1>()").arg(ip.type.name);
     if (ip.type.isComplex()) {
         cpp << QString("    const %1 s = %2;").arg(ip.type.name, val);
diff --git a/tests/test_list_rust.cpp b/tests/test_list_rust.cpp
index b43fdfa..3cd2adb 100644
--- a/tests/test_list_rust.cpp
+++ b/tests/test_list_rust.cpp
@@ -111,6 +111,9 @@ QVariant Persons::userName(int row) const
 bool Persons::setUserName(int row, const QVariant& value)
 {
     bool set = false;
+    if (!value.canConvert(qMetaTypeId<QString>())) {
+        return false;
+    }
     const QString s = value.value<QString>();    set = persons_set_data_user_name(m_d, row, s.utf16(), s.length());
     if (set) {
         QModelIndex index = createIndex(row, 0, row);
diff --git a/tests/test_tree_rust.cpp b/tests/test_tree_rust.cpp
index f56c57c..3d0d1c2 100644
--- a/tests/test_tree_rust.cpp
+++ b/tests/test_tree_rust.cpp
@@ -127,6 +127,9 @@ QVariant Persons::userName(const QModelIndex& index) const
 bool Persons::setUserName(const QModelIndex& index, const QVariant& value)
 {
     bool set = false;
+    if (!value.canConvert(qMetaTypeId<QString>())) {
+        return false;
+    }
     const QString s = value.value<QString>();    set = persons_set_data_user_name(m_d, index.internalId(), s.utf16(), s.length());
     if (set) {
         emit dataChanged(index, index);