---
title: ASP.NET Core Blazor templated components
author: guardrex
description: Learn how templated components can accept one or more UI templates as parameters, which can then be used as part of the component's rendering logic.
monikerRange: '>= aspnetcore-3.1'
ms.author: riande
ms.custom: mvc
ms.date: 11/08/2022
uid: blazor/components/templated-components
---
# ASP.NET Core Blazor templated components

This article explains how templated components can accept one or more UI templates as parameters, which can then be used as part of the component's rendering logic.

:::moniker range=">= aspnetcore-7.0"

Templated components are components that accept one or more UI templates as parameters, which can then be used as part of the component's rendering logic. Templated components allow you to author higher-level components that are more reusable than regular components. A couple of examples include:

* A table component that allows a user to specify templates for the table's header, rows, and footer.
* A list component that allows a user to specify a template for rendering items in a list.

A templated component is defined by specifying one or more component parameters of type <xref:Microsoft.AspNetCore.Components.RenderFragment> or <xref:Microsoft.AspNetCore.Components.RenderFragment%601>. A render fragment represents a segment of UI to render. <xref:Microsoft.AspNetCore.Components.RenderFragment%601> takes a type parameter that can be specified when the render fragment is invoked.

> [!NOTE]
> For more information on <xref:Microsoft.AspNetCore.Components.RenderFragment>, see <xref:blazor/components/index#child-content-render-fragments>.

Often, templated components are generically typed, as the following `TableTemplate` component demonstrates. The generic type `<T>` in this example is used to render `IReadOnlyList<T>` values, which in this case is a series of pet rows in a component that displays a table of pets.

`Shared/TableTemplate.razor`:

:::code language="razor" source="~/../blazor-samples/7.0/BlazorSample_WebAssembly/Shared/templated-components/TableTemplate.razor":::

When using a templated component, the template parameters can be specified using child elements that match the names of the parameters. In the following example, `<TableHeader>...</TableHeader>` and `<RowTemplate>...<RowTemplate>` supply <xref:Microsoft.AspNetCore.Components.RenderFragment%601> templates for `TableHeader` and `RowTemplate` of the `TableTemplate` component.

Specify the `Context` attribute on the component element when you want to specify the content parameter name for implicit child content (without any wrapping child element). In the following example, the `Context` attribute appears on the `TableTemplate` element and applies to all <xref:Microsoft.AspNetCore.Components.RenderFragment%601> template parameters.

`Pages/Pets1.razor`:

:::code language="razor" source="~/../blazor-samples/7.0/BlazorSample_WebAssembly/Pages/templated-components/Pets1.razor":::

Alternatively, you can change the parameter name using the `Context` attribute on the <xref:Microsoft.AspNetCore.Components.RenderFragment%601> child element. In the following example, the `Context` is set on `RowTemplate` rather than `TableTemplate`:

`Pages/Pets2.razor`:

:::code language="razor" source="~/../blazor-samples/7.0/BlazorSample_WebAssembly/Pages/templated-components/Pets2.razor" highlight="10":::

Component arguments of type <xref:Microsoft.AspNetCore.Components.RenderFragment%601> have an implicit parameter named `context`, which can be used. In the following example, `Context` isn't set. `@context.{PROPERTY}` supplies pet values to the template, where `{PROPERTY}` is a `Pet` property:

`Pages/Pets3.razor`:

:::code language="razor" source="~/../blazor-samples/7.0/BlazorSample_WebAssembly/Pages/templated-components/Pets3.razor" highlight="11-12":::

When using generic-typed components, the type parameter is inferred if possible. However, you can explicitly specify the type with an attribute that has a name matching the type parameter, which is `TItem` in the preceding example:

`Pages/Pets4.razor`:

:::code language="razor" source="~/../blazor-samples/7.0/BlazorSample_WebAssembly/Pages/templated-components/Pets4.razor" highlight="5":::

## Additional resources

* <xref:blazor/performance#define-reusable-renderfragments-in-code>
* [Blazor samples GitHub repository (`dotnet/blazor-samples`)](https://github.com/dotnet/blazor-samples)

:::moniker-end

:::moniker range=">= aspnetcore-6.0 < aspnetcore-7.0"

Templated components are components that accept one or more UI templates as parameters, which can then be used as part of the component's rendering logic. Templated components allow you to author higher-level components that are more reusable than regular components. A couple of examples include:

* A table component that allows a user to specify templates for the table's header, rows, and footer.
* A list component that allows a user to specify a template for rendering items in a list.

A templated component is defined by specifying one or more component parameters of type <xref:Microsoft.AspNetCore.Components.RenderFragment> or <xref:Microsoft.AspNetCore.Components.RenderFragment%601>. A render fragment represents a segment of UI to render. <xref:Microsoft.AspNetCore.Components.RenderFragment%601> takes a type parameter that can be specified when the render fragment is invoked.

> [!NOTE]
> For more information on <xref:Microsoft.AspNetCore.Components.RenderFragment>, see <xref:blazor/components/index#child-content-render-fragments>.

Often, templated components are generically typed, as the following `TableTemplate` component demonstrates. The generic type `<T>` in this example is used to render `IReadOnlyList<T>` values, which in this case is a series of pet rows in a component that displays a table of pets.

`Shared/TableTemplate.razor`:

:::code language="razor" source="~/../blazor-samples/6.0/BlazorSample_WebAssembly/Shared/templated-components/TableTemplate.razor":::

When using a templated component, the template parameters can be specified using child elements that match the names of the parameters. In the following example, `<TableHeader>...</TableHeader>` and `<RowTemplate>...<RowTemplate>` supply <xref:Microsoft.AspNetCore.Components.RenderFragment%601> templates for `TableHeader` and `RowTemplate` of the `TableTemplate` component.

Specify the `Context` attribute on the component element when you want to specify the content parameter name for implicit child content (without any wrapping child element). In the following example, the `Context` attribute appears on the `TableTemplate` element and applies to all <xref:Microsoft.AspNetCore.Components.RenderFragment%601> template parameters.

`Pages/Pets1.razor`:

:::code language="razor" source="~/../blazor-samples/6.0/BlazorSample_WebAssembly/Pages/templated-components/Pets1.razor":::

Alternatively, you can change the parameter name using the `Context` attribute on the <xref:Microsoft.AspNetCore.Components.RenderFragment%601> child element. In the following example, the `Context` is set on `RowTemplate` rather than `TableTemplate`:

`Pages/Pets2.razor`:

:::code language="razor" source="~/../blazor-samples/6.0/BlazorSample_WebAssembly/Pages/templated-components/Pets2.razor" highlight="10":::

Component arguments of type <xref:Microsoft.AspNetCore.Components.RenderFragment%601> have an implicit parameter named `context`, which can be used. In the following example, `Context` isn't set. `@context.{PROPERTY}` supplies pet values to the template, where `{PROPERTY}` is a `Pet` property:

`Pages/Pets3.razor`:

:::code language="razor" source="~/../blazor-samples/6.0/BlazorSample_WebAssembly/Pages/templated-components/Pets3.razor" highlight="11-12":::

When using generic-typed components, the type parameter is inferred if possible. However, you can explicitly specify the type with an attribute that has a name matching the type parameter, which is `TItem` in the preceding example:

`Pages/Pets4.razor`:

:::code language="razor" source="~/../blazor-samples/6.0/BlazorSample_WebAssembly/Pages/templated-components/Pets4.razor" highlight="5":::

## Additional resources

* <xref:blazor/performance#define-reusable-renderfragments-in-code>
* [Blazor samples GitHub repository (`dotnet/blazor-samples`)](https://github.com/dotnet/blazor-samples)

:::moniker-end

:::moniker range=">= aspnetcore-5.0 < aspnetcore-6.0"

Templated components are components that accept one or more UI templates as parameters, which can then be used as part of the component's rendering logic. Templated components allow you to author higher-level components that are more reusable than regular components. A couple of examples include:

* A table component that allows a user to specify templates for the table's header, rows, and footer.
* A list component that allows a user to specify a template for rendering items in a list.

A templated component is defined by specifying one or more component parameters of type <xref:Microsoft.AspNetCore.Components.RenderFragment> or <xref:Microsoft.AspNetCore.Components.RenderFragment%601>. A render fragment represents a segment of UI to render. <xref:Microsoft.AspNetCore.Components.RenderFragment%601> takes a type parameter that can be specified when the render fragment is invoked.

> [!NOTE]
> For more information on <xref:Microsoft.AspNetCore.Components.RenderFragment>, see <xref:blazor/components/index#child-content-render-fragments>.

Often, templated components are generically typed, as the following `TableTemplate` component demonstrates. The generic type `<T>` in this example is used to render `IReadOnlyList<T>` values, which in this case is a series of pet rows in a component that displays a table of pets.

`Shared/TableTemplate.razor`:

:::code language="razor" source="~/../blazor-samples/5.0/BlazorSample_WebAssembly/Shared/templated-components/TableTemplate.razor":::

When using a templated component, the template parameters can be specified using child elements that match the names of the parameters. In the following example, `<TableHeader>...</TableHeader>` and `<RowTemplate>...<RowTemplate>` supply <xref:Microsoft.AspNetCore.Components.RenderFragment%601> templates for `TableHeader` and `RowTemplate` of the `TableTemplate` component.

Specify the `Context` attribute on the component element when you want to specify the content parameter name for implicit child content (without any wrapping child element). In the following example, the `Context` attribute appears on the `TableTemplate` element and applies to all <xref:Microsoft.AspNetCore.Components.RenderFragment%601> template parameters.

`Pages/Pets1.razor`:

:::code language="razor" source="~/../blazor-samples/5.0/BlazorSample_WebAssembly/Pages/templated-components/Pets1.razor":::

Alternatively, you can change the parameter name using the `Context` attribute on the <xref:Microsoft.AspNetCore.Components.RenderFragment%601> child element. In the following example, the `Context` is set on `RowTemplate` rather than `TableTemplate`:

`Pages/Pets2.razor`:

:::code language="razor" source="~/../blazor-samples/5.0/BlazorSample_WebAssembly/Pages/templated-components/Pets2.razor" highlight="10":::

Component arguments of type <xref:Microsoft.AspNetCore.Components.RenderFragment%601> have an implicit parameter named `context`, which can be used. In the following example, `Context` isn't set. `@context.{PROPERTY}` supplies pet values to the template, where `{PROPERTY}` is a `Pet` property:

`Pages/Pets3.razor`:

:::code language="razor" source="~/../blazor-samples/5.0/BlazorSample_WebAssembly/Pages/templated-components/Pets3.razor" highlight="11-12":::

When using generic-typed components, the type parameter is inferred if possible. However, you can explicitly specify the type with an attribute that has a name matching the type parameter, which is `TItem` in the preceding example:

`Pages/Pets4.razor`:

:::code language="razor" source="~/../blazor-samples/5.0/BlazorSample_WebAssembly/Pages/templated-components/Pets4.razor" highlight="5":::

## Additional resources

* <xref:blazor/performance#define-reusable-renderfragments-in-code>
* [Blazor samples GitHub repository (`dotnet/blazor-samples`)](https://github.com/dotnet/blazor-samples)

:::moniker-end

:::moniker range="< aspnetcore-5.0"

Templated components are components that accept one or more UI templates as parameters, which can then be used as part of the component's rendering logic. Templated components allow you to author higher-level components that are more reusable than regular components. A couple of examples include:

* A table component that allows a user to specify templates for the table's header, rows, and footer.
* A list component that allows a user to specify a template for rendering items in a list.

A templated component is defined by specifying one or more component parameters of type <xref:Microsoft.AspNetCore.Components.RenderFragment> or <xref:Microsoft.AspNetCore.Components.RenderFragment%601>. A render fragment represents a segment of UI to render. <xref:Microsoft.AspNetCore.Components.RenderFragment%601> takes a type parameter that can be specified when the render fragment is invoked.

> [!NOTE]
> For more information on <xref:Microsoft.AspNetCore.Components.RenderFragment>, see <xref:blazor/components/index#child-content-render-fragments>.

Often, templated components are generically typed, as the following `TableTemplate` component demonstrates. The generic type `<T>` in this example is used to render `IReadOnlyList<T>` values, which in this case is a series of pet rows in a component that displays a table of pets.

`Shared/TableTemplate.razor`:

:::code language="razor" source="~/../blazor-samples/3.1/BlazorSample_WebAssembly/Shared/templated-components/TableTemplate.razor":::

When using a templated component, the template parameters can be specified using child elements that match the names of the parameters. In the following example, `<TableHeader>...</TableHeader>` and `<RowTemplate>...<RowTemplate>` supply <xref:Microsoft.AspNetCore.Components.RenderFragment%601> templates for `TableHeader` and `RowTemplate` of the `TableTemplate` component.

Specify the `Context` attribute on the component element when you want to specify the content parameter name for implicit child content (without any wrapping child element). In the following example, the `Context` attribute appears on the `TableTemplate` element and applies to all <xref:Microsoft.AspNetCore.Components.RenderFragment%601> template parameters.

`Pages/Pets1.razor`:

:::code language="razor" source="~/../blazor-samples/3.1/BlazorSample_WebAssembly/Pages/templated-components/Pets1.razor":::

Alternatively, you can change the parameter name using the `Context` attribute on the <xref:Microsoft.AspNetCore.Components.RenderFragment%601> child element. In the following example, the `Context` is set on `RowTemplate` rather than `TableTemplate`:

`Pages/Pets2.razor`:

:::code language="razor" source="~/../blazor-samples/3.1/BlazorSample_WebAssembly/Pages/templated-components/Pets2.razor" highlight="10":::

Component arguments of type <xref:Microsoft.AspNetCore.Components.RenderFragment%601> have an implicit parameter named `context`, which can be used. In the following example, `Context` isn't set. `@context.{PROPERTY}` supplies pet values to the template, where `{PROPERTY}` is a `Pet` property:

`Pages/Pets3.razor`:

:::code language="razor" source="~/../blazor-samples/3.1/BlazorSample_WebAssembly/Pages/templated-components/Pets3.razor" highlight="11-12":::

When using generic-typed components, the type parameter is inferred if possible. However, you can explicitly specify the type with an attribute that has a name matching the type parameter, which is `TItem` in the preceding example:

`Pages/Pets4.razor`:

:::code language="razor" source="~/../blazor-samples/3.1/BlazorSample_WebAssembly/Pages/templated-components/Pets4.razor" highlight="5":::

## Additional resources

* <xref:blazor/performance#define-reusable-renderfragments-in-code>
* <xref:blazor/components/index#generic-type-parameter-support>
* [Blazor samples GitHub repository (`dotnet/blazor-samples`)](https://github.com/dotnet/blazor-samples)

:::moniker-end