title: extjs update the value of a column in all rows in grid
body: <p>I have created a gridpanel with column 'name' and 'sex' For the toolbar, I have created a combobox of sex. After I select the value of combos 'sex' , the column 'sex' of all rows in the gridpanel will be update to the selected value. How can I update the column of all rows? Thanks.</p>