Blazor Pie Chart

A Blazor Bootstrap pie chart component is a circular chart that shows the proportional values of different categories.

Parameters

Name	Type	Default	Required	Description	Added Version
Height	int			Gets or sets chart height.	1.0.0
Width	int			Get or sets chart width.	1.0.0

Methods

Name	Return type	Description	Added Version
AddDataAsync	ChartData	Adds data to bar chart.	1.10.0
AddDatasetAsync	ChartData	Adds dataset to bar chart.	1.10.0
InitializeAsync	Task	Initialize Bar Chart.	1.0.0
UpdateAsync	Task	Update Bar Chart.	1.0.0

ChartData Members

Property Name	Type	Default	Required	Description	Added Version
Labels	List<string>	null	✔️	Gets or sets the Labels.	1.0.0
Datasets	List<IChartDataset>	null	✔️	Gets or sets the Datasets.	1.0.0

PieChartDataset Members

info

PieChartDataset implements IChartDataset.

Property Name	Type	Default	Required	Description	Added Version
BackgroundColor	List<string>	null		Get or sets the BackgroundColor.	1.0.0
BorderColor	List<string>	null		Get or sets the BorderColor.	1.0.0
BorderWidth	List<double>	null		Get or sets the BorderWidth.	1.0.0
Clip	string	null		How to clip relative to chartArea. Positive value allows overflow, negative value clips that many pixels inside chartArea. 0 = clip at chartArea. Clipping can also be configured per side: clip: {left: 5, top: false, right: -2, bottom: 0}	1.0.0
Data	List<double>	null		Get or sets the Data.	1.0.0
Datalabels	PieChartDatasetDataLabels			Get or sets the data labels
Hidden	bool	false		Configures the visibility state of the dataset. Set it to true, to hide the dataset from the chart.	1.0.0
HoverBackgroundColor	List<string>	null	✔️	Get or sets the HoverBackgroundColor.	1.0.0
HoverBorderColor	List<string>	null	✔️	Get or sets the HoverBorderColor.	1.0.0
HoverBorderWidth	List<double>	null	✔️	Get or sets the HoverBorderWidth.	1.0.0
Type	string	null	✔️	Get or sets the chart type.	1.0.0

PieChartDatasetDataLabels Members

Property Name	Type	Default	Required	Description	Added Version
Anchor	string?	center		Gets or sets the anchor.	1.10.2
BorderWidth	double?	2		Gets or sets the border width.	1.10.2

PieChartOptions Members

info

PieChartOptions implements ChartOptions.

Property Name	Type	Default	Required	Description	Added Version
Locale	string?			Gets or sets the locale. By default, the chart is using the default locale of the platform which is running on.	1.10.0
Plugins	PieChartPlugins			Gets or sets the Plugins.	1.10.2
Responsive	bool	false		Gets or sets the Responsive.	1.0.0

Examples

Prerequisites

Refer to the getting started guide for setting up charts.

How it works

In the following example, a categorical 12-color palette is used.

tip

For data visualization, you can use the predefined palettes ColorBuilder.CategoricalTwelveColors for a 12-color palette and ColorBuilder.CategoricalSixColors for a 6-color palette. These palettes offer a range of distinct and visually appealing colors that can be applied to represent different categories or data elements in your visualizations.

<PieChart @ref="pieChart" Width="500" Class="mb-5" />

<Button Type="ButtonType.Button" Color="ButtonColor.Primary" Size="Size.Small" @onclick="async () => await RandomizeAsync()"> Randomize </Button>
<Button Type="ButtonType.Button" Color="ButtonColor.Primary" Size="Size.Small" @onclick="async () => await AddDatasetAsync()"> Add Dataset </Button>
<Button Type="ButtonType.Button" Color="ButtonColor.Primary" Size="Size.Small" @onclick="async () => await AddDataAsync()">Add Data</Button>

@code {
    private PieChart pieChart = default!;
    private PieChartOptions pieChartOptions = default!;
    private ChartData chartData = default!;
    private string[]? backgroundColors;

    private int datasetsCount = 0;
    private int dataLabelsCount = 0;

    private Random random = new();

    protected override void OnInitialized()
    {
        backgroundColors = ColorBuilder.CategoricalTwelveColors;
        chartData = new ChartData { Labels = GetDefaultDataLabels(4), Datasets = GetDefaultDataSets(1) };

        pieChartOptions = new();
        pieChartOptions.Responsive = true;
        pieChartOptions.Plugins.Title.Text = "2022 - Sales";
        pieChartOptions.Plugins.Title.Display = true;
    }

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            await pieChart.InitializeAsync(chartData, pieChartOptions);
        }
        await base.OnAfterRenderAsync(firstRender);
    }

    private async Task RandomizeAsync()
    {
        if (chartData is null || chartData.Datasets is null || !chartData.Datasets.Any()) return;

        var newDatasets = new List<IChartDataset>();

        foreach (var dataset in chartData.Datasets)
        {
            if (dataset is PieChartDataset pieChartDataset
                && pieChartDataset is not null
                && pieChartDataset.Data is not null)
            {
                var count = pieChartDataset.Data.Count;

                var newData = new List<double>();
                for (var i = 0; i < count; i++)
                {
                    newData.Add(random.Next(0, 100));
                }

                pieChartDataset.Data = newData;
                newDatasets.Add(pieChartDataset);
            }
        }

        chartData.Datasets = newDatasets;

        await pieChart.UpdateAsync(chartData, pieChartOptions);
    }

    private async Task AddDatasetAsync()
    {
        if (chartData is null || chartData.Datasets is null) return;

        var chartDataset = GetRandomPieChartDataset();
        chartData = await pieChart.AddDatasetAsync(chartData, chartDataset, pieChartOptions);
    }

    private async Task AddDataAsync()
    {
        if (dataLabelsCount >= 12)
            return;

        if (chartData is null || chartData.Datasets is null)
            return;

        var data = new List<IChartDatasetData>();
        foreach (var dataset in chartData.Datasets)
        {
            if (dataset is PieChartDataset pieChartDataset)
                data.Add(new PieChartDatasetData(pieChartDataset.Label, random.Next(0, 100), backgroundColors![dataLabelsCount]));
        }

        chartData = await pieChart.AddDataAsync(chartData, GetNextDataLabel(), data);

        dataLabelsCount += 1;
    }

    #region Data Preparation

    private List<IChartDataset> GetDefaultDataSets(int numberOfDatasets)
    {
        var datasets = new List<IChartDataset>();

        for (var index = 0; index < numberOfDatasets; index++)
        {
            datasets.Add(GetRandomPieChartDataset());
        }

        return datasets;
    }

    private PieChartDataset GetRandomPieChartDataset()
    {
        datasetsCount += 1;
        return new() { Label = $"Team {datasetsCount}", Data = GetRandomData(), BackgroundColor = GetRandomBackgroundColors() };
    }

    private List<double> GetRandomData()
    {
        var data = new List<double>();
        for (var index = 0; index < dataLabelsCount; index++)
        {
            data.Add(random.Next(0, 100));
        }

        return data;
    }

    private List<string> GetRandomBackgroundColors()
    {
        var colors = new List<string>();
        for (var index = 0; index < dataLabelsCount; index++)
        {
            colors.Add(backgroundColors![index]);
        }

        return colors;
    }

    private List<string> GetDefaultDataLabels(int numberOfLabels)
    {
        var labels = new List<string>();
        for (var index = 0; index < numberOfLabels; index++)
        {
            labels.Add(GetNextDataLabel());
            dataLabelsCount += 1;
        }

        return labels;
    }

    private string GetNextDataLabel() => $"Product {dataLabelsCount + 1}";

    private string GetNextDataBackgrounfColor() => backgroundColors![dataLabelsCount];

    #endregion  Data Preparation
}

See the demo here.

Data labels

<PieChart @ref="pieChart" Width="500" Class="mb-5" />

<Button Type="ButtonType.Button" Color="ButtonColor.Primary" Size="Size.Small" @onclick="async () => await RandomizeAsync()"> Randomize </Button>
<Button Type="ButtonType.Button" Color="ButtonColor.Primary" Size="Size.Small" @onclick="async () => await AddDataAsync()">Add Data</Button>

@code {
    private PieChart pieChart = default!;
    private PieChartOptions pieChartOptions = default!;
    private ChartData chartData = default!;
    private string[]? backgroundColors;

    private int datasetsCount = 0;
    private int dataLabelsCount = 0;

    private Random random = new();

    protected override void OnInitialized()
    {
        backgroundColors = ColorBuilder.CategoricalTwelveColors;
        chartData = new ChartData { Labels = GetDefaultDataLabels(4), Datasets = GetDefaultDataSets(3) };

        pieChartOptions = new();
        pieChartOptions.Responsive = true;
        pieChartOptions.Plugins.Title.Text = "2022 - Sales";
        pieChartOptions.Plugins.Title.Display = true;
    }

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            // pass the plugin name to enable the data labels
            await pieChart.InitializeAsync(chartData: chartData, chartOptions: pieChartOptions, plugins: new string[] { "ChartDataLabels" });
        }
        await base.OnAfterRenderAsync(firstRender);
    }

    private async Task RandomizeAsync()
    {
        if (chartData is null || chartData.Datasets is null || !chartData.Datasets.Any()) return;

        var newDatasets = new List<IChartDataset>();

        foreach (var dataset in chartData.Datasets)
        {
            if (dataset is PieChartDataset pieChartDataset
                && pieChartDataset is not null
                && pieChartDataset.Data is not null)
            {
                var count = pieChartDataset.Data.Count;

                var newData = new List<double>();
                for (var i = 0; i < count; i++)
                {
                    newData.Add(random.Next(0, 100));
                }

                pieChartDataset.Data = newData;
                newDatasets.Add(pieChartDataset);
            }
        }

        chartData.Datasets = newDatasets;

        await pieChart.UpdateAsync(chartData, pieChartOptions);
    }

    private async Task AddDataAsync()
    {
        if (dataLabelsCount >= 12)
            return;

        if (chartData is null || chartData.Datasets is null)
            return;

        var data = new List<IChartDatasetData>();
        foreach (var dataset in chartData.Datasets)
        {
            if (dataset is PieChartDataset pieChartDataset)
                data.Add(new PieChartDatasetData(pieChartDataset.Label, random.Next(0, 100), backgroundColors![dataLabelsCount]));
        }

        chartData = await pieChart.AddDataAsync(chartData, GetNextDataLabel(), data);

        dataLabelsCount += 1;
    }

    #region Data Preparation

    private List<IChartDataset> GetDefaultDataSets(int numberOfDatasets)
    {
        var datasets = new List<IChartDataset>();

        for (var index = 0; index < numberOfDatasets; index++)
        {
            var dataset = GetRandomPieChartDataset();

            if (index == 0)
                dataset.Datalabels.Anchor = "end";
            else if (index == numberOfDatasets - 1)
                dataset.Datalabels.Anchor = "end";
            else
                dataset.Datalabels.Anchor = "center";

            datasets.Add(dataset);
        }

        return datasets;
    }

    private PieChartDataset GetRandomPieChartDataset()
    {
        datasetsCount += 1;
        return new() { Label = $"Team {datasetsCount}", Data = GetRandomData(), BackgroundColor = GetRandomBackgroundColors() };
    }

    private List<double> GetRandomData()
    {
        var data = new List<double>();
        for (var index = 0; index < dataLabelsCount; index++)
        {
            data.Add(random.Next(0, 100));
        }

        return data;
    }

    private List<string> GetRandomBackgroundColors()
    {
        var colors = new List<string>();
        for (var index = 0; index < dataLabelsCount; index++)
        {
            colors.Add(backgroundColors![index]);
        }

        return colors;
    }

    private List<string> GetDefaultDataLabels(int numberOfLabels)
    {
        var labels = new List<string>();
        for (var index = 0; index < numberOfLabels; index++)
        {
            labels.Add(GetNextDataLabel());
            dataLabelsCount += 1;
        }

        return labels;
    }

    private string GetNextDataLabel() => $"Product {dataLabelsCount + 1}";

    private string GetNextDataBackgrounfColor() => backgroundColors![dataLabelsCount];

    #endregion  Data Preparation
}

See the demo here.

Change legend position

This sample demonstrates how to change the position of the chart legend.

<PieChart @ref="pieChart" Width="500" Class="mb-5" />

<Button Type="ButtonType.Button" Color="ButtonColor.Primary" Size="Size.Small" @onclick="PositionTopAsync"> Position: top </Button>
<Button Type="ButtonType.Button" Color="ButtonColor.Primary" Size="Size.Small" @onclick="PositionRightAsync"> Position: right </Button>
<Button Type="ButtonType.Button" Color="ButtonColor.Primary" Size="Size.Small" @onclick="PositionBottomAsync"> Position: bottom </Button>
<Button Type="ButtonType.Button" Color="ButtonColor.Primary" Size="Size.Small" @onclick="PositionLeftAsync"> Position: left </Button>

@code {
    private PieChart pieChart = default!;
    private PieChartOptions pieChartOptions = default!;
    private ChartData chartData = default!;
    private string[]? backgroundColors;

    private int datasetsCount = 0;
    private int dataLabelsCount = 0;

    private Random random = new();

    protected override void OnInitialized()
    {
        backgroundColors = ColorBuilder.CategoricalTwelveColors;
        chartData = new ChartData { Labels = GetDefaultDataLabels(4), Datasets = GetDefaultDataSets(1) };

        pieChartOptions = new();
        pieChartOptions.Responsive = true;
        pieChartOptions.Plugins.Title.Text = "2022 - Sales";
        pieChartOptions.Plugins.Title.Display = true;

        pieChartOptions.Plugins.Legend.Position = "right";
    }

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            await pieChart.InitializeAsync(chartData, pieChartOptions);
        }
        await base.OnAfterRenderAsync(firstRender);
    }

    private async Task PositionTopAsync() => await UpdatePositionAsync("top");
    private async Task PositionRightAsync() => await UpdatePositionAsync("right");
    private async Task PositionBottomAsync() => await UpdatePositionAsync("bottom");
    private async Task PositionLeftAsync() => await UpdatePositionAsync("left");

    private async Task UpdatePositionAsync(string position)
    {
        pieChartOptions.Plugins.Legend.Position = position;
        await pieChart.UpdateAsync(chartData, pieChartOptions);
    }

    #region Data Preparation

    private List<IChartDataset> GetDefaultDataSets(int numberOfDatasets)
    {
        var datasets = new List<IChartDataset>();

        for (var index = 0; index < numberOfDatasets; index++)
        {
            datasets.Add(GetRandomPieChartDataset());
        }

        return datasets;
    }

    private PieChartDataset GetRandomPieChartDataset()
    {
        datasetsCount += 1;
        return new() { Label = $"Team {datasetsCount}", Data = GetRandomData(), BackgroundColor = GetRandomBackgroundColors() };
    }

    private List<double> GetRandomData()
    {
        var data = new List<double>();
        for (var index = 0; index < dataLabelsCount; index++)
        {
            data.Add(random.Next(0, 100));
        }

        return data;
    }

    private List<string> GetRandomBackgroundColors()
    {
        var colors = new List<string>();
        for (var index = 0; index < dataLabelsCount; index++)
        {
            colors.Add(backgroundColors![index]);
        }

        return colors;
    }

    private List<string> GetDefaultDataLabels(int numberOfLabels)
    {
        var labels = new List<string>();
        for (var index = 0; index < numberOfLabels; index++)
        {
            labels.Add(GetNextDataLabel());
            dataLabelsCount += 1;
        }

        return labels;
    }

    private string GetNextDataLabel() => $"Product {dataLabelsCount + 1}";

    private string GetNextDataBackgrounfColor() => backgroundColors![dataLabelsCount];

    #endregion  Data Preparation
}

See the demo here.