razor

Also @template and @taghelper for declarative templates and tag helpers in razor files. (inside viewimports)


@model MyViewModel

<grid data-source="Customers">
    <column model="FirstName" />
    <column model="LastName" />
    <column model='@FirstName + " " + LastName' />
    <item-template>

    </item-template>
</grid>

@model MyViewModel
<table>
    <thead>
        <th asp-display-name-for="@Customers.FirstName"></th>
        <th asp-display-name-for="@Customers.LastName"></th>
        <th>Full Name</th>
    </thead>
    <tbody>
        <tr asp-repeat="Customers">
            <td>@item.FirstName</td>
            <td>@item.LastName</td>
            <td>@(item.FirstName + " " + item.LastName)</td>
        </tr>
    </tbody>
</table>



@Html.RepeatFor(m.Customers,
    @<tr>
        <td>@item.FirstName</td>
        <td>@item.LastName</td>
        <td>@(item.FirstName + " " + item.LastName)</td>
    </tr>
)

public static IHtmlContent RepeatFor<TItem>(IEnumerable<TItem> items, Func<TItem, IHtmlContent> renderItem)
{
    var builder = new HtmlContentBuilder();
    foreach (var item in items)
    {
        builder.AppendHtml(renderItem(item));
    }
    return builder;
}

<foo blah="SomeBlah">


<tr asp-repeat="Model.Customers" my-prop="Something">
    <td>@item.FirstName</td>
    <td>@item.LastName</td>
    <td>@(item.FirstName + " " + item.LastName)</td>
</tr>

[HtmlTargetElement("*", Attributes = "asp-repeat")]
[ContentContextParameterName("item")]
public class RepeatTagHelper<TContext> : TagHelper<TContext>
{
    public IEnumerable<TItem> Items { get; set; }

    public override async Task ProcessAsync(TagHelperContext<TContext> context, TagHelperOutput output)
    {
        foreach (var item in Items)
        {
            output.AppendHtml(await context.GetChildContentAsync(item));
        }

        output.TagName = null;
    }
}


<table>
    <thead>
        <th>@Html.DisplayNameFor(m => m.FirstName)</th>
        <th>@Html.DisplayNameFor(m => m.LastName)</th>
        <th>Full Name</th>
    </thead>
    <tbody>
foreach (var customer in Model.Customers)
{
        <tr>
            <td>@Model.FirstName</td>
            <td>@Model.LastName</td>
            <td>@(FirstName + " " + LastName)</td>
        </tr>
}
    </tbody>
</table>


<ul data-source="Categories">
    <li>@Model.Name</li>
</ul>



public class CustomerViewModel
{
    public IList<Customer> Customers { get; set; }
}

[RestrictChildren("column"]
public class GridTagHelper : TagHelper
{
    public IEnumerable<GridColumnTagHelper> Columns { get; set; }
    
    public ModelExpression DataSource { get; set; }

    [Unbound]
    public GridContext GridContext { get; set; }

    public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
    {
        // Force processing of children now
        await output.GetChildContentAsync();

        // Build the grid using the declartions from the children

    }
}

[HtmlTargetElement("column")]
public class GridColumnTagHelper : ChildTagHelper<GridTagHelper>
{
    public ModelExpression Field { get; set; }

    public string Format { get; set; }

    public bool Enabled { get; set; }

    [NotBound]
    public HtmlTemplate Template { get; set; }

    public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
    {
        Template = HtmlTemplate.Create(await output.GetChildContentAsync());
    }
}