Blazor Chart Overview

The Blazor Chart component allows you to visualize data to your users in a meaningful way so they can draw conclusions. You can use a variety of graph types and control all aspects of the component's appearance - from colors and fonts, to paddings, margins and templates.

The Chart component is part of Telerik UI for Blazor, a professional grade UI library with 110+ native components for building modern and feature-rich applications. To try it out sign up for a free 30-day trial.

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Creating Blazor Chart

1. Add the <TelerikChart> tag to your razor page.
2. Define Chart series and bind them to data.
3. Configure the category axis (X axis). Either set a CategoryField for each <ChartSeries>, or provide all Categories in bulk in a <ChartCategoryAxis> tag.
4. Set a <ChartTitle> and the Position of the <ChartLegend>. To make the legend appear, define a Name for each <ChartSeries>.

Basic chart

Basic chart and common settings/elements

<TelerikChart>
    <ChartSeriesItems>
        <ChartSeries Type="ChartSeriesType.Line" Name="Product 1 (bound to simple data)" Data="@simpleData">
        </ChartSeries>
        <ChartSeries Type="ChartSeriesType.Line" Name="Product 2 (bound to model)" Data="@modelData" Field="@nameof(MyDataModel.SecondSeriesValue)">
            <ChartSeriesLabels Template="#=value# in #=dataItem.ExtraData# quarter" Visible="true"></ChartSeriesLabels>
        </ChartSeries>
    </ChartSeriesItems>

    <ChartValueAxes>
        <ChartValueAxis Color="red"></ChartValueAxis>
    </ChartValueAxes>

    <ChartCategoryAxes>
        <ChartCategoryAxis Categories="@xAxisItems"></ChartCategoryAxis>
    </ChartCategoryAxes>

    <ChartTitle Text="Quarterly sales trend"></ChartTitle>

    <ChartLegend Position="Telerik.Blazor.ChartLegendPosition.Bottom">
    </ChartLegend>
</TelerikChart>

@code {
    public class MyDataModel
    {
        public int SecondSeriesValue { get; set; }
        public string ExtraData { get; set; }
    }

    public List<MyDataModel> modelData = new List<MyDataModel>()
    {
        new MyDataModel() { SecondSeriesValue = 1, ExtraData = "first" },
        new MyDataModel() { SecondSeriesValue = 5, ExtraData = "second" },
        new MyDataModel() { SecondSeriesValue = 3, ExtraData = "third" },
        new MyDataModel() { SecondSeriesValue = 2, ExtraData = "fourth" },
    };

    public List<object> simpleData = new List<object>() { 10, 2, 7, 5 };

    public string[] xAxisItems = new string[] { "Q1", "Q2", "Q3", "Q4" };
}

Chart Elements

Customize Chart Elements - Nested Tags Settings

When configuring nested properties and child elements in your chart, the inner tags will contain their parent tag name and add specifics to its end. In general the structure of such nested tags will be <Chart*Category**Specifics*> where the Category can be one of the following:

• CategoryAxis
• ChartArea
• Legend
• PlotArea
• SeriesItems
• Title
• Tooltip
• ValueAxis
• XAxes
• YAxes
• and others

To customize the chart, look for nested tags and their properties - the inner tags will contain their parent tag name and add specifics to its end. For example, the ChartSeries tag has a ChartSeriesLabels tag that exposes configuration options and more child tags.

Chart Title

You can add a short description of the Chart's purpose by using the ChartTitle tag and the Text parameter. In addition, the ChartTitle Description parameter allows the app to provide accessible text content, which screen readers announce when the Chart gains focus.

Using ChartTitle

<TelerikChart>
    <ChartTitle Text="Product Sales" Description="Product Sales by Year and Country"></ChartTitle>
</TelerikChart>

Chart Subtitle

You can add a descriptive text that enriches the Title by adding the ChartSubtitle and assigning a value for the Text parameter.

Chart Size

To control the chart size, use its Width and Height properties. You can read more on how they work in the Dimensions article.

You can also set the chart size in percentage values so it occupies its container when it renders. If the parent container size changes, you must call the chart's Refresh() C# method after the DOM has been redrawn and the new container dimensions are rendered. You can do this when you explicitly change container sizes (like in the example below), or from code that gets called by events like window.resize. You can find an example and guidelines for making Charts refresh on window.resize in the knowledge base article for responsive Chart.

Change the 100% chart size dynamically to have a responsive chart

You can make a responsive chart

<TelerikButton OnClick="@ResizeChart">Resize the container and redraw the chart</TelerikButton>

<div style="border: 1px solid red;width:@ContainerWidth; height: @ContainerHeight">

    <TelerikChart Width ="100%" Height="100%" @ref="theChart">

        <ChartSeriesItems>
            <ChartSeries Type="ChartSeriesType.Column" Name="Product 1" Data="@someData">
            </ChartSeries>
        </ChartSeriesItems>
        <ChartCategoryAxes>
            <ChartCategoryAxis Categories="@xAxisItems"></ChartCategoryAxis>
        </ChartCategoryAxes>
        <ChartTitle Text="Quarterly sales trend"></ChartTitle>

    </TelerikChart>

</div>

@code {
    string ContainerWidth { get; set; } = "400px";
    string ContainerHeight { get; set; } = "300px";
    Telerik.Blazor.Components.TelerikChart theChart { get; set; }

    async Task ResizeChart()
    {
        //resize the container
        ContainerHeight = "500px";
        ContainerWidth = "800px";

        //give time to the framework and browser to resize the actual DOM so the chart can use the expected size
        await Task.Delay(20);

        //redraw the chart
        theChart.Refresh();
    }

    public List<object> someData = new List<object>() { 10, 2, 7, 5 };

    public string[] xAxisItems = new string[] { "Q1", "Q2", "Q3", "Q4" };
}

Chart Parameters

The following table lists Chart parameters, which are not discussed elsewhere in the component documentation.

Parameter	Type and Default value	Description
Width	string	Controls the width of the Chart.
Height	string	Controls the height of the Chart.
Class	string	Renders a custom CSS class on the <div class="k-chart"> element.
Transitions	bool?	Controls if the Chart renders animations.

Chart Reference and Methods

To execute Chart methods, obtain reference to the component instance via @ref.

Method	Description
Refresh	Use the method to programmatically re-render the Chart.
ResetDrilldownLevel	Use the method to programmatically reset the drilldown level of the Chart. For more information refer to the DrillDown article.

<TelerikButton OnClick="@RefreshChart">Refresh Chart</TelerikButton>

<TelerikChart @ref="ChartRef" />

@code {
    public TelerikChart ChartRef;

    private void RefreshChart()
    {
        ChartRef.Refresh();
    }
}

Next Steps

• Data bind the Chart
• Explore the Chart events
• Learn more about Chart Tooltips

See Also

• Live Demos: Chart
• Chart API Reference