SO社区，
我将D3直方图作为Angular指令进行制作，我希望它能够随着读取的数据的变化而相应地更改/更新。换句话说，我正在使用Angular来观察数据的变化，并且（希望）在每次更改数据时重绘直方图。
这可能主要是关于D3更新和绑定数据的问题，因为$ watchCollection似乎工作正常。即使我已经通过this tutorial对d3图表添加元素，我仍然无法将其应用于直方图。我认为直方图中的元素嵌套的方式让我感到困惑......
上下文：理想情况下，这个直方图将从一个数组中读取，从多个Ajax调用返回的数据将被存储到该数组中。因此，每当一组新数据到达时，直方图将自己增长另一个条形。这就是为什么我想知道如何正确更新图表和x轴的原因。
谢谢！ ：）
JS小提琴在这里：http://jsfiddle.net/santina/wrtenjny/1/
d3部分的代码在这里，主要取自mbostock的可排序条形图。
// Aesthetic settings
var margin = {top: 20, right: 50, bottom: 20, left: 50},
width = document.getElementById('performance').clientWidth - margin.left - margin.right ||
940 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom,
barColor = "steelblue",
axisColor = "whitesmoke",
axisLabelColor = "grey",
yText = "# QUERIES",
xText = "BEACON IDs";
// Inputs to the d3 graph
var data = scope[attrs.data];
// A formatter for counts.
var formatCount = d3.format(",.0f");
// Set the scale, separate the first bar by a bar width from y-axis
var x = d3.scale.ordinal()
.rangeRoundBands([0, width], .1, 1);
var y = d3.scale.linear()
.range([height, 0]);
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.tickFormat(formatCount);
// Initialize histogram
var svg = d3.select(".histogram-chart")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
function drawAxis(){
data.forEach(function(d) {
d.nqueries = +d.nqueries;
});
x.domain(data.map(function(d) { return d.name; }));
y.domain([0, d3.max(data, function(d) { return d.nqueries; })]);
// Draw x-axis
svg.append("g")
.attr("class", "x-axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis)
.append("text")
.attr("y", 6)
.attr("dy", "-0.71em")
.attr("x", width )
.style("text-anchor", "end")
.style("fill", axisLabelColor)
.text(xText);
// Draw y-axis
svg.append("g")
.attr("class", "y-axis")
.call(yAxis)
.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 6)
.attr("dy", ".71em")
.style("text-anchor", "end")
.style("fill", axisLabelColor)
.text(yText);
// Change axis color
d3.selectAll("path").attr("fill", axisColor);
}
function updateAxis(){
console.log(data);
data.forEach(function(d) {
d.nqueries = +d.nqueries;
});
x.domain(data.map(function(d) { return d.name; }));
y.domain([0, d3.max(data, function(d) { return d.nqueries; })]);
svg.selectAll("g.y_axis").call(yAxis);
svg.selectAll("g.x_axis").call(xAxis);
}
function drawHistogram(){
drawAxis();
var bar = svg.selectAll(".bar")
.data(data)
.enter().append("g")
.attr("class", "barInfo");
bar.append("rect")
.attr("class", "bar")
.attr("x", function(d){ return x(d.name) })
.attr("width", x.rangeBand())
.attr("y", function(d){ return y(d.nqueries) })
.attr("height", function(d) { return height - y(d.nqueries); })
.attr("fill", barColor);
bar.append("text")
.attr("y", function(d){ return y(d.nqueries) })
.attr("x", function(d){ return x(d.name) })
.attr("dy", "-1px")
.attr("dx", x.rangeBand()/2 )
.attr("text-anchor", "middle")
.attr("class", "numberLabel")
.text(function(d) { return formatCount(d.nqueries); });
}
// Doesn't work :(
function updateHistogram(){
console.log("updating");
// Redefine scale and update axis
updateAxis();
// Select
var bar = svg.selectAll(".barInfo").data(data);
// Update - rect
var rects = bar.selectAll("rect")
.attr("class", "bar")
.attr("x", function(d){ return x(d.name) })
.attr("width", x.rangeBand());
// Update
var texts = bar.selectAll("text")
.attr("x", function(d){ return x(d.name) })
.attr("dx", x.rangeBand()/2 );
// Enter
bar.enter().append("g")
.attr("class", "bar").selectAll("rect").append("rect")
.attr("class", "bar")
.attr("x", function(d){ return x(d.name) })
.attr("width", x.rangeBand())
.attr("y", function(d){ return y(d.nqueries) })
.attr("height", function(d) { return height - y(d.nqueries); })
.attr("fill", barColor);
bar.enter().append("g")
.attr("class", "bar").selectAll("text").append("text")
.attr("y", function(d){ return y(d.nqueries) })
.attr("x", function(d){ return x(d.name) })
.attr("dy", "-1px")
.attr("dx", x.rangeBand()/2 )
.attr("text-anchor", "middle")
.attr("class", "numberLabel")
.text(function(d) { return formatCount(d.nqueries); });
}
drawHistogram();