Ext 3中grid的autoHeight的bug fixing: maxHeight
? ? 在Ext3的grid中，autoHeight有个遗留的bug，不知道后续有没有被修掉。这个bug是说max height设定的值不起作用。也就是说，autoHeight的情况下，虽然设定了max height的值，但是当grid的height的值超过了max height，还是会继续增加，而不会已出现滚动条形式出现。由于我们的开发基于版本3，不能期待后续的版本了。
? ?在查找了一些资料，并修正了存在的bug之后，终于可以使得autoHeight的属性正常被使用。
? ?首先，复写gridView中的layout方法：
??layout : function(initial) {
if (!this.mainBody) {return; // notrendered}var grid = this.grid, gridEl = grid.getGridEl(), gridSize = gridEl.getSize(true), gridWidth = gridSize.width, gridHeight = gridSize.height, scroller = this.scroller, scrollStyle, headerHeight, scrollHeight;if (gridWidth < 20 || gridHeight < 20) {return;}if (grid.autoHeight) {scrollStyle = scroller.dom.style;if (Ext.isNumber(grid.maxHeight) && gridHeight >= grid.maxHeight) {gridHeight = grid.maxHeight;this.el.setSize(gridWidth, gridHeight);headerHeight = this.mainHd.getHeight();scrollHeight = gridHeight - headerHeight;scroller.setSize(gridWidth, scrollHeight);scrollStyle.overflow = '';scrollStyle.position = '';} else {this.el.setSize();scroller.setSize();scrollStyle.overflow = 'visible';if (Ext.isWebKit) {scrollStyle.position = 'static';}}} else {this.el.setSize(gridWidth, gridHeight);headerHeight = this.mainHd.getHeight();scrollHeight = gridHeight - headerHeight;scroller.setSize(gridWidth, scrollHeight);if (this.innerHd) {this.innerHd.style.width = (gridWidth) + "px";}}if (this.forceFit || (initial === true && this.autoFill)) {if (this.lastViewWidth != gridWidth) {this.fitColumns(false, false);this.lastViewWidth = gridWidth;}} else {this.autoExpand();this.syncHeaderScroll();}this.onLayout(gridWidth, scrollHeight);}?其次，每次我们对一个grid进行手动add之后，都要synSize一下这个grid：
?
_synsizeGridWhenAddData : function(grid) {grid.store.on("add", function(tis, records, opt) {grid.syncSize();}, this);},