Ext 三中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; // not
			rendered
		}

		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);
			},