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问题:

I've seen a few posts on this topic:

Razor Nested Layouts with Cascading Sections

MVC 3 - Nested layouts - sections don't render in Areas

And it always seems to be problematic. However they are both pretty old so wondering if things have changed.

Basically I have a master layout, and 3 different body templates based on what kind of page it is. For examples sake:

_Layout.cshtml

<html lang="en">
    <head>
    </head>
    <body style="padding: 50px 0;">
        <header class="navbar navbar-default navbar-fixed-top" role="banner">
            @Html.Partial("_MenuPartial")
        </header>
        <ol class="breadcrumbs">
            @RenderSection("breadcrumbs", true);
        </ol>
        <section>
            @RenderBody();
        </section>
            <footer class="navbar navbar-default navbar-fixed-bottom">
            @Html.Partial("_FooterPartial")
        </footer>
        @Html.Partial("_ScriptInitPartial")
    </body>
</html>

_LayoutForEdit.cshtml

<div class="panel panel-primary">
    <div class="panel-body">
        <div class="col-lg-2">
            <ul class="nav nav-pills nav-stacked">
                @RenderSection("tabs", true)
            </ul>
        </div>
        <div class="col-lg-10">
            <div class="tab-content">
                @RenderBody()
            </div>
        </div>
    </div>
    <div class="panel-footer">
        <button class="btn btn-primary" data-bind="enable: Entity.isValid, click: save">Save</button>
    </div>
</div>

Now this renders fine when called. Almost.

The rendering of sections must be in the child layout it seems. If I try to put the breadcrumbs in the _Layout.cshtml, it will fail because _LayoutForEdit.cshtml never rendered it. How can I fix this?

The following sections have been defined but have not been rendered for the layout page "~/Views/Shared/_LayoutForEdit.cshtml": "breadcrumbs".

回答1:

I know it's an old question. I thought I'd share this anyway in case anyone else runs into this (like I did).

At the bottom of your child layout, you define a section with the same name as the section in the parent layout. Inside of this section you simply put a @RenderSection, again specifying the same name as before. Once this is in place, you essentially have the child layout "bypass" content from pages, up to its parent layout:

@section breadcrumbs {
    @RenderSection("breadcrumbs", true)
}

回答2:

Not sure if you still need help, but I'll answer anyways.

There RenderSection method takes the following parameters according to the MSDN Documentation:

public HelperResult RenderSection( string name, bool required )

Parameters
name
     Type: System.String
     The section to render.
required
     Type: System.Boolean
     true to specify that the section is required; otherwise, false.

Change the call to:

@RenderSection("breadcrumbs", false);

If the section "required" parameter is false, it will not give an error if that section is not included by a view.