You could use a EditorWithMask, but keep in mind that a column has a datatype and if your column datatype is not compatible with the expected Editor datatype the results are unpredictable
EditorWithMask currency_editor;
DefaultEditorOwnerSettings editorSettings = new DefaultEditorOwnerSettings();
editorSettings.DataType = typeof(decimal);
currency_editor = new EditorWithMask(new DefaultEditorOwner(editorSettings));
editorSettings.MaskInput = "€ nnn.nn";
e.Row.Cells["decimal_column_name"].Editor = mask_editor;