Consider adding HTML templates

[JeanCollas]

Would adding custom local HTML templates not be a good option to consider?
Something similar to the following would be an option for the implementation:

@functions{
    IHtmlContent DispItem(string id, string name, string description)
    {
        <li>
            <a href="/manage/@id">@name</a>
            <span>@description</span>
        </li>
    }
}
...
<ul id="list1">
    @foreach(var item in items1)
    {
        DispItem(item.Id, item.Name, item.Description)
    }
</ul>

<ul id="list2">
    @foreach(var item in items2)
    {
        DispItem(item.Id, item.Name, item.Description)
    }
</ul>

Creating a separate file and model for this kind of display is sometimes too much as compared as what it intends to do.
Simplifying this by allowing local templates would be helpful.

Except if I missed it, it is not possible at this time (except by using html strings concat or external sub-pages/components).

[mkArtakMSFT]

Looks like we have a similar issue we're considering: https://github.com/aspnet/Razor/issues/821

[mkArtakMSFT]

/cc: @DamianEdwards

[JeanCollas]

Any plan to implement it?
I think it is actually similar to this, existing in former versions:

https://docs.microsoft.com/en-us/aspnet/web-pages/overview/ui-layouts-and-themes/creating-and-using-a-helper-in-an-aspnet-web-pages-site

https://weblogs.asp.net/scottgu/asp-net-mvc-3-and-the-helper-syntax-within-razor

[rynowak]

@NTaylorMullen - do we have a doc about the existing support for templates in Razor? I looked at https://docs.microsoft.com/en-us/aspnet/core/mvc/views/razor and couldn't find anything about templates.

@JeanCollas - We have an existing feature that's somewhat limited. #821 tracks some improvements we want to make, but that won't be part of this release.

Example:

@{
    Func<dynamic, object> foo = @<text>This works @item!</text>;
    @foo("")
}

More examples from our tests: https://github.com/aspnet/Razor/blob/dev/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/Templates.cshtml

[NTaylorMullen]

do we have a doc about the existing support for templates in Razor?

We don't have an official doc. However, we do have some ad-hoc conversations that have some great template examples given the APIs that are available today: #281

[RandyBuchholz]

This proposal - Design-Time Directive [Language Feature Proposal] #1747 - might be relevant here. It addresses an approach to templating.

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