vtkDataArrayTemplate: Add a safe method to change an element with vtkVariant.

This fix is in reference to bug report 0013143.

Common/Core/vtkDataArrayTemplate.h

@@ -212,6 +212,10 @@ public:
   // Set a value in the array from a vtkVariant.
   void SetVariantValue(vtkIdType id, vtkVariant value);
 
+  // Description:
+  // Insert a value in the array from a vtkVariant.
+  void InsertVariantValue(vtkIdType id, vtkVariant value);
+
   // Description:
   // Insert data at the end of the array. Return its location in the array.
   vtkIdType InsertNextValue(T f);

Common/Core/vtkDataArrayTemplate.txx

@@ -979,6 +979,22 @@ void vtkDataArrayTemplate<T>::SetVariantValue(vtkIdType id, vtkVariant value)
     }
 }
 
+//----------------------------------------------------------------------------
+template <class T>
+void vtkDataArrayTemplate<T>::InsertVariantValue(vtkIdType id, vtkVariant value)
+{
+  bool valid;
+  T toInsert = vtkVariantCast<T>(value, &valid);
+  if (valid)
+    {
+    this->InsertValue(id, toInsert);
+    }
+  else
+    {
+    vtkErrorMacro("unable to set value of type " << value.GetType());
+    }
+}
+
 //----------------------------------------------------------------------------
 template <class T>
 vtkIdType vtkDataArrayTemplate<T>::InsertNextValue(T f)