Getting Started with Blazor TreeMap Component

7 Oct 202216 minutes to read

This section briefly explains about how to include Blazor TreeMap component in your Blazor Server App and Blazor WebAssembly App using Visual Studio.

Prerequisites

Create a new Blazor App in Visual Studio

You can create Blazor Server App or Blazor WebAssembly App using Visual Studio in one of the following ways,

Install Syncfusion Blazor TreeMap NuGet in the App

Syncfusion Blazor components are available in nuget.org. To use Syncfusion Blazor components in the application, add reference to the corresponding NuGet. Refer to NuGet packages topic for available NuGet packages list with component details and Benefits of using individual NuGet packages.

To add Blazor TreeMap component in the app, open the NuGet package manager in Visual Studio (Tools → NuGet Package Manager → Manage NuGet Packages for Solution), search for Syncfusion.Blazor.TreeMap and then install it.

Register Syncfusion Blazor Service

Open ~/_Imports.razor file and import the Syncfusion.Blazor namespace.

@using Syncfusion.Blazor

Now, register the Syncfusion Blazor Service in the Blazor Server App or Blazor WebAssembly App. Here, Syncfusion Blazor Service is registered by setting IgnoreScriptIsolation property as true to load the scripts externally in the next steps.

From 2022 Vol-1 (20.1) version, the default value of IgnoreScriptIsolation is changed to true. It is not necessary to set the IgnoreScriptIsolation property to refer scripts externally, since the default value has already been changed to true, and this property is obsolete.

Blazor Server App

  • For .NET 6 app, open the ~/Program.cs file and register the Syncfusion Blazor Service.

  • For .NET 5 and .NET 3.X app, open the ~/Startup.cs file and register the Syncfusion Blazor Service.

using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Components.Web;
using Syncfusion.Blazor;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddRazorPages();
builder.Services.AddServerSideBlazor();
builder.Services.AddSyncfusionBlazor();

var app = builder.Build();
....
using Syncfusion.Blazor;

namespace BlazorApplication
{
    public class Startup
    {
        ...
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();
            services.AddServerSideBlazor();
            services.AddSyncfusionBlazor();
        }
        ...
    }
}

Blazor WebAssembly App

Open ~/Program.cs file and register the Syncfusion Blazor Service in the client web app.

using Microsoft.AspNetCore.Components.Web;
using Microsoft.AspNetCore.Components.WebAssembly.Hosting;
using Syncfusion.Blazor;

var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("#app");
builder.RootComponents.Add<HeadOutlet>("head::after");

builder.Services.AddScoped(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });

builder.Services.AddSyncfusionBlazor();
await builder.Build().RunAsync();
....
using Syncfusion.Blazor;

namespace WebApplication1
{
    public class Program
    {
        public static async Task Main(string[] args)
        {
            ....
            builder.Services.AddSyncfusionBlazor();
            await builder.Build().RunAsync();
        }
    }
}

Add Style Sheet

Checkout the Blazor Themes topic to learn different ways (Static Web Assets, CDN and CRG) to refer themes in Blazor application, and to have the expected appearance for Syncfusion Blazor components. Here, the theme is referred using Static Web Assets. Refer to Enable static web assets usage topic to use static assets in your project.

To add theme to the app, open the NuGet package manager in Visual Studio (Tools → NuGet Package Manager → Manage NuGet Packages for Solution), search for Syncfusion.Blazor.Themes and then install it. Then, the theme style sheet from NuGet can be referred as follows,

If you are using Syncfusion.Blazor single NuGet, you don’t have to refer Syncfusion.Blazor.Themes NuGet. Since style sheets already inside the assets of Syncfusion.Blazor NuGet.

Blazor Server App

  • For .NET 6 app, add the Syncfusion bootstrap5 theme in the <head> of the ~/Pages/_Layout.cshtml file.

  • For .NET 5 and .NET 3.X app, add the Syncfusion bootstrap5 theme in the <head> of the ~/Pages/_Host.cshtml file.

<head>
    ...
    <link href="_content/Syncfusion.Blazor.Themes/bootstrap5.css" rel="stylesheet" />
    <!--Refer theme style sheet as below if you are using Syncfusion.Blazor Single NuGet-->
    <!--<link href="_content/Syncfusion.Blazor/styles/bootstrap5.css" rel="stylesheet" />-->
</head>
<head>
    ...
    <link href="_content/Syncfusion.Blazor.Themes/bootstrap5.css" rel="stylesheet" />
    <!--Refer theme style sheet as below if you are using Syncfusion.Blazor Single NuGet-->
    <!--<link href="_content/Syncfusion.Blazor/styles/bootstrap5.css" rel="stylesheet" />-->
</head>

Blazor WebAssembly App

For Blazor WebAssembly App, Refer the theme style sheet from NuGet in the <head> of wwwroot/index.html file in the client web app.

<head>
    ...
    <link href="_content/Syncfusion.Blazor.Themes/bootstrap5.css" rel="stylesheet" />
    <!--Refer theme style sheet as below if you are using Syncfusion.Blazor Single NuGet-->
    <!--<link href="_content/Syncfusion.Blazor/styles/bootstrap5.css" rel="stylesheet" />-->
</head>

Add Script Reference

Checkout Adding Script Reference topic to learn different ways to add script reference in Blazor Application. In this getting started walk-through, the required scripts are referred using Static Web Assets externally inside the <head> as follows. Refer to Enable static web assets usage topic to use static assets in your project.

Blazor Server App

  • For .NET 6 app, Refer script in the <head> of the ~/Pages/_Layout.cshtml file.

  • For .NET 5 and .NET 3.X app, Refer script in the <head> of the ~/Pages/_Host.cshtml file.

<head>
    ....
    <link href="_content/Syncfusion.Blazor.Themes/bootstrap5.css" rel="stylesheet" />
    <script src="_content/Syncfusion.Blazor.Core/scripts/syncfusion-blazor.min.js" type="text/javascript"></script>
    <!--Use below script reference if you are using Syncfusion.Blazor Single NuGet-->
    <!--<script  src="_content/Syncfusion.Blazor/scripts/syncfusion-blazor.min.js"  type="text/javascript"></script>-->
</head>
<head>
    ....
    <link href="_content/Syncfusion.Blazor.Themes/bootstrap5.css" rel="stylesheet" />
    <script src="_content/Syncfusion.Blazor.Core/scripts/syncfusion-blazor.min.js" type="text/javascript"></script>
    <!--Use below script reference if you are using Syncfusion.Blazor Single NuGet-->
    <!--<script  src="_content/Syncfusion.Blazor/scripts/syncfusion-blazor.min.js"  type="text/javascript"></script>-->
</head>

Blazor WebAssembly App

For Blazor WebAssembly App, Refer script in the <head> of the ~/index.html file.

<head>
    ....
    <link href="_content/Syncfusion.Blazor.Themes/bootstrap5.css" rel="stylesheet" />
    <script src="_content/Syncfusion.Blazor.Core/scripts/syncfusion-blazor.min.js" type="text/javascript"></script>
    <!--Use below script reference if you are using Syncfusion.Blazor Single NuGet-->
    <!--<script  src="_content/Syncfusion.Blazor/scripts/syncfusion-blazor.min.js"  type="text/javascript"></script>-->
</head>

Syncfusion recommends to reference scripts using Static Web Assets, CDN and CRG by disabling JavaScript isolation for better loading performance of the Blazor application.

Add Blazor TreeMap component

  • Open ~/_Imports.razor file or any other page under the ~/Pages folder where the component is to be added and import the Syncfusion.Blazor.TreeMap namespace.
@using Syncfusion.Blazor
@using Syncfusion.Blazor.TreeMap
  • Now, add the Syncfusion TreeMap component in razor file. Here, the TreeMap component is added in the ~/Pages/Index.razor file under the ~/Pages folder.

  • You can use the DataSource property to load the car sales details in the TreeMap component. Specify a field name from the data source in the WeightValuePath property to calculate the TreeMap item size.

<SfTreeMap DataSource="GrowthReport"
            WeightValuePath="GDP"
            TValue="Country">
</SfTreeMap>

@code {
    public class Country
    {
        public string Name { get; set; }
        public double GDP { get; set; }
    }
    public List<Country> GrowthReport = new List<Country> {
        new Country  {Name="United States", GDP=17946 },
        new Country  {Name="China", GDP=10866 },
        new Country  {Name="Japan", GDP=4123 },
        new Country  {Name="Germany", GDP=3355 },
        new Country  {Name="United Kingdom", GDP=2848 },
        new Country  {Name="France", GDP=2421 },
        new Country  {Name="India", GDP=2073 },
        new Country  {Name="Italy", GDP=1814 },
        new Country  {Name="Brazil", GDP=1774 },
        new Country  {Name="Canada", GDP=1550 }
    };
}
  • Press Ctrl+F5 (Windows) or +F5 (macOS) to run the application. Then, the Syncfusion Blazor TreeMap component will be rendered in the default web browser.

Blazor TreeMap Component

Adding labels in TreeMap items

Add label text to the leaf items in the TreeMap component by setting the field name from data source in the LabelPath property in the TreeMapLeafItemSettings, and it provides information to the user about the leaf items.

<SfTreeMap DataSource="GrowthReport"
            WeightValuePath="GDP"
            TValue="Country">
    <TreeMapLeafItemSettings LabelPath="Name" Fill="lightgray"></TreeMapLeafItemSettings>
</SfTreeMap>

Refer to the code block to know about the property value of the GrowthReport.

Blazor TreeMap with Label

Adding title to TreeMap

Add a title using the Text property in the TreeMapTitleSettings to provide quick information to the user about the items rendered in the TreeMap.

<SfTreeMap DataSource="GrowthReport"
            WeightValuePath="GDP"
            TValue="Country">
    <TreeMapTitleSettings Text="Top 10 countries by GDP Nominal - 2015"></TreeMapTitleSettings>
    <TreeMapLeafItemSettings LabelPath="Name" Fill="lightgray"></TreeMapLeafItemSettings>
</SfTreeMap>

Refer to the code block to know the property value of the GrowthReport.

Blazor TreeMap with Title

View Sample in GitHub.

Apply color mapping

The color mapping supports customization of item colors based on the underlying value received from the bound data source. Specify the field name from which the values have to be compared for the items in the RangeColorValuePath property in SfTreeMap. Also, specify range value and color in the TreeMapLeafColorMapping. Here, in this example, “Orange” is specified for the range “0 - 3000” and “Green” is specified for the range “3000 - 20000”.

<SfTreeMap DataSource="GrowthReport"
            WeightValuePath="GDP"
            TValue="Country"
            RangeColorValuePath="GDP">
    <TreeMapTitleSettings Text="Top 10 countries by GDP Nominal - 2015"></TreeMapTitleSettings>
    <TreeMapLeafItemSettings LabelPath="Name" Fill="lightgray">
        <TreeMapLeafColorMappings>
            <TreeMapLeafColorMapping From="0" To="3000" Color="@(new string[] { "Orange" })"></TreeMapLeafColorMapping>
            <TreeMapLeafColorMapping From="3000" To="20000" Color="@(new string[] { "Green" })"></TreeMapLeafColorMapping>
        </TreeMapLeafColorMappings>
    </TreeMapLeafItemSettings>
</SfTreeMap>

Refer to the code block to know about the property value of the GrowthReport.

Blazor TreeMap with Color Mapping

Enable legend

Legend items are used to denote the color mapping categories and show the legend for the TreeMap by setting the Visible property to true in the TreeMapLegendSettings.

<SfTreeMap DataSource="GrowthReport"
            WeightValuePath="GDP"
            TValue="Country"
            RangeColorValuePath="GDP">
    <TreeMapTitleSettings Text="Top 10 countries by GDP Nominal - 2015"></TreeMapTitleSettings>
    <TreeMapLeafItemSettings LabelPath="Name" Fill="lightgray">
        <TreeMapLeafColorMappings>
            <TreeMapLeafColorMapping From="0" To="3000" Color="@(new string[] { "Orange" })"></TreeMapLeafColorMapping>
            <TreeMapLeafColorMapping From="3000" To="20000" Color="@(new string[] { "Green" })"></TreeMapLeafColorMapping>
        </TreeMapLeafColorMappings>
    </TreeMapLeafItemSettings>
    <TreeMapLegendSettings Visible="true"></TreeMapLegendSettings>
</SfTreeMap>

Refer to the code block to know about the property value of the GrowthReport.

Blazor TreeMap with Legend

Enable tooltip

When space constraints prevents from displaying information using data labels, the tooltip comes in handy. The tooltip can be enabled by setting the Visible property to true in the TreeMapTooltipSettings.

<SfTreeMap DataSource="GrowthReport"
            WeightValuePath="GDP"
            TValue="Country"
            RangeColorValuePath="GDP">
    <TreeMapTitleSettings Text="Top 10 countries by GDP Nominal - 2015"></TreeMapTitleSettings>
    <TreeMapLeafItemSettings LabelPath="Name" Fill="lightgray">
        <TreeMapLeafColorMappings>
            <TreeMapLeafColorMapping From="0" To="3000" Color="@(new string[] { "Orange" })"></TreeMapLeafColorMapping>
            <TreeMapLeafColorMapping From="3000" To="20000" Color="@(new string[] { "Green" })"></TreeMapLeafColorMapping>
        </TreeMapLeafColorMappings>
    </TreeMapLeafItemSettings>
    <TreeMapLegendSettings Visible="true"></TreeMapLegendSettings>
    <TreeMapTooltipSettings Visible="true"></TreeMapTooltipSettings>
</SfTreeMap>

Refer to the code block to know about the property value of the GrowthReport.

Blazor TreeMap with Tooltip

You can also explore our Blazor TreeMap example that shows you how to render and configure the treemap.

See also