如何在JQGrid的行编辑中禁用某些单元格的编辑？

$("#jqGrid").jqGrid({
    // ...
    colModel: [
        { name: "column1", editable: true },
        { name: "column2", editable: false },
        { name: "column3", editable: true }
    ],
    // ...
});

$("#jqGrid").jqGrid({
    // ...
    beforeEditCell: function(rowid, cellname, value, iRow, iCol) {
        if (cellname === "column2") {
            return false;
        }
    },
    // ...
});