遍历Grid每行，每格的数据

var grid = .....;
var store = grid.store;
var rowCount = store.getCount(); //记录数
var cm = grid.getColumnModel();
var colCount = cm.getColumnCount(); //列数
var view = grid.getView();
for(i=0;i<rowCount;i++){
  for(j=0;j<colCount;j++){
    var cell = view.getCell(i,j);
    alert(cell.innerHTML);//第i行j列的数据
  }
}