Blazor是微软推出的基于.NET的前端框架,允许开发者使用C#编写前端逻辑,而Chart.js是一款简单易用的JavaScript图表库,支持多种图表类型。在Blazor项目中使用Chart.js绘制图表,需要结合Blazor的JavaScript互操作能力,让C#代码可以调用Chart.js的相关功能。

环境准备
首先需要在Blazor项目中引入Chart.js的库文件,推荐通过CDN的方式引入,在项目的wwwroot/index.html(Blazor WebAssembly)或者Pages/_Host.cshtml(Blazor Server)的<head>标签中添加如下引用:
<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
同时需要创建一个JavaScript文件,用于封装Chart.js的初始化、更新等操作,方便Blazor通过互操作调用。在wwwroot目录下创建chartInterop.js文件,内容如下:
// 存储已创建的图表实例
const chartInstances = {};
// 初始化图表
function initChart(canvasId, chartType, chartData, chartOptions) {
const canvas = document.getElementById(canvasId);
if (!canvas) {
console.error(`未找到id为${canvasId}的画布元素`);
return;
}
const ctx = canvas.getContext('2d');
// 如果已存在同id的图表,先销毁
if (chartInstances[canvasId]) {
chartInstances[canvasId].destroy();
}
// 创建新图表实例
chartInstances[canvasId] = new Chart(ctx, {
type: chartType,
data: chartData,
options: chartOptions
});
return canvasId;
}
// 更新图表数据
function updateChartData(canvasId, newData) {
const chart = chartInstances[canvasId];
if (!chart) {
console.error(`未找到id为${canvasId}的图表实例`);
return;
}
chart.data = newData;
chart.update();
}
创建Blazor互操作服务
为了方便在Blazor组件中调用上面的JavaScript方法,我们可以创建一个对应的C#服务类。在项目中创建ChartInteropService.cs文件:
using Microsoft.JSInterop;
using System.Threading.Tasks;
public class ChartInteropService
{
private readonly IJSRuntime _jsRuntime;
public ChartInteropService(IJSRuntime jsRuntime)
{
_jsRuntime = jsRuntime;
}
/// <summary>
/// 初始化图表
/// </summary>
/// <param name="canvasId">画布元素id</param>
/// <param name="chartType">图表类型</param>
/// <param name="chartData">图表数据</param>
/// <param name="chartOptions">图表配置</param>
public async Task InitChartAsync(string canvasId, string chartType, object chartData, object chartOptions)
{
await _jsRuntime.InvokeVoidAsync("initChart", canvasId, chartType, chartData, chartOptions);
}
/// <summary>
/// 更新图表数据
/// </summary>
/// <param name="canvasId">画布元素id</param>
/// <param name="newData">新的图表数据</param>
public async Task UpdateChartDataAsync(string canvasId, object newData)
{
await _jsRuntime.InvokeVoidAsync("updateChartData", canvasId, newData);
}
}
然后在Program.cs中注册这个服务,方便后续依赖注入使用:
builder.Services.AddScoped<ChartInteropService>();
绘制基础折线图
接下来我们创建一个Blazor组件,实现折线图的绘制。创建一个LineChart.razor组件:
@page "/line-chart"
@inject ChartInteropService ChartInterop
<h3>Blazor折线图示例</h3>
<canvas id="lineChartCanvas" width="800" height="400"></canvas>
@code {
private string canvasId = "lineChartCanvas";
// 图表数据
private object chartData = new
{
labels = new[] { "一月", "二月", "三月", "四月", "五月", "六月" },
datasets = new[]
{
new
{
label = "销售额",
data = new[] { 120, 190, 300, 500, 200, 300 },
borderColor = "rgb(75, 192, 192)",
backgroundColor = "rgba(75, 192, 192, 0.2)",
tension = 0.1
}
}
};
// 图表配置
private object chartOptions = new
{
responsive = true,
plugins = new
{
title = new
{
display = true,
text = "上半年销售额趋势"
}
}
};
protected override async Task OnAfterRenderAsync(bool firstRender)
{
if (firstRender)
{
// 初始化折线图
await ChartInterop.InitChartAsync(canvasId, "line", chartData, chartOptions);
}
}
}
运行项目访问/line-chart页面,就可以看到绘制好的折线图。这里需要注意,图表初始化要放在OnAfterRenderAsync方法中,并且firstRender为true的时候执行,确保DOM元素已经渲染完成,JavaScript可以正常获取到画布元素。
绘制柱状图与动态更新数据
除了折线图,我们也可以很方便地绘制柱状图,并且实现数据的动态更新。创建BarChart.razor组件:
@page "/bar-chart"
@inject ChartInteropService ChartInterop
<h3>Blazor柱状图示例</h3>
<canvas id="barChartCanvas" width="800" height="400"></canvas>
<button class="btn btn-primary" @onclick="UpdateChart">更新数据</button>
@code {
private string canvasId = "barChartCanvas";
private Random random = new Random();
private object chartData = new
{
labels = new[] { "产品A", "产品B", "产品C", "产品D", "产品E" },
datasets = new[]
{
new
{
label = "销量",
data = new[] { 50, 80, 120, 90, 150 },
backgroundColor = new[]
{
"rgba(255, 99, 132, 0.2)",
"rgba(54, 162, 235, 0.2)",
"rgba(255, 206, 86, 0.2)",
"rgba(75, 192, 192, 0.2)",
"rgba(153, 102, 255, 0.2)"
},
borderColor = new[]
{
"rgb(255, 99, 132)",
"rgb(54, 162, 235)",
"rgb(255, 206, 86)",
"rgb(75, 192, 192)",
"rgb(153, 102, 255)"
},
borderWidth = 1
}
}
};
private object chartOptions = new
{
responsive = true,
scales = new
{
y = new
{
beginAtZero = true
}
}
};
protected override async Task OnAfterRenderAsync(bool firstRender)
{
if (firstRender)
{
await ChartInterop.InitChartAsync(canvasId, "bar", chartData, chartOptions);
}
}
private async Task UpdateChart()
{
// 生成新的随机数据
var newData = new
{
labels = new[] { "产品A", "产品B", "产品C", "产品D", "产品E" },
datasets = new[]
{
new
{
label = "销量",
data = new[]
{
random.Next(30, 200),
random.Next(30, 200),
random.Next(30, 200),
random.Next(30, 200),
random.Next(30, 200)
},
backgroundColor = new[]
{
"rgba(255, 99, 132, 0.2)",
"rgba(54, 162, 235, 0.2)",
"rgba(255, 206, 86, 0.2)",
"rgba(75, 192, 192, 0.2)",
"rgba(153, 102, 255, 0.2)"
},
borderColor = new[]
{
"rgb(255, 99, 132)",
"rgb(54, 162, 235)",
"rgb(255, 206, 86)",
"rgb(75, 192, 192)",
"rgb(153, 102, 255)"
},
borderWidth = 1
}
}
};
await ChartInterop.UpdateChartDataAsync(canvasId, newData);
}
}
点击更新数据按钮,就可以看到柱状图的数据会随机变化,实现动态更新的效果。如果需要绘制其他类型的图表,只需要把InitChartAsync方法中的第二个参数改成对应的图表类型即可,比如pie是饼图,doughnut是环形图,radar是雷达图。
常见问题说明
- 如果图表没有正常显示,首先检查Chart.js的CDN引用是否成功,然后检查
chartInterop.js是否正确引入,在index.html或_Host.cshtml中添加<script src="chartInterop.js"></script>引用。 - Blazor Server项目中,JavaScript互操作是异步的,不要在
OnInitialized方法中直接初始化图表,因为此时DOM还没有渲染完成,会导致获取不到画布元素。 - 如果需要在图表中显示中文,确保Chart.js的版本支持中文显示,一般最新版本都默认支持,不需要额外配置。
BlazorChart_js图表绘制JavaScript互操作修改时间:2026-07-09 21:06:50