What is the Grails GSP equivalent of ASP's ContentPlaceHolder?
I've been playing around a lot with the templating/layout concepts in Grails GSP. I've ben using layouts/content blocks for imitating ASP's master page behavior.
For example, I am using the tag <g:pageProperty /> in a template to leave a "placeholder" which can be overridden using a <content> tag:
myTemplate.gsp:
<body>
<g:pageProperty name="page.to开发者_如何转开发pDiv" />
</body>
<html>
<head>
<meta name="layout" content="myTemplate"></meta>
</head>
<body>
<content tag="topDiv">
My top div
</content>
</body>
</html>
This works great for "appending" content to some spot within a template. However, I really want the behavior I can get in ASP.NET's master pages... which is to provide a "default" rendering of some content, and allow optional overriding. In an ASP.NET Master page, it would look like this:
myMaster.master:
<asp:ContentPlaceHolder id="something" runat="server">
<div>Default text/html here</div>
</asp:ContentPlaceHolder>
<asp:Content contentPlaceHolderId="something" runat="server">
Overriden content here!! I don't need to override this though :)
</asp:Content>
There are a few different days you could accomplish this. The g:pageProperty is equivalent to the Sitemesh decorator:getProperty tag, so you can use a default attribute to indicate the default text to use. For example:
<g:pageProperty name="page.topDiv" default="Default text/html here"/>
However, I don't know of a clean way to get HTML content in there. You could use a g:if tag to test for that property and specify default behavior if it doesn't exist:
<g:if test="${pageProperty(name:'page.topDiv')}">
<g:pageProperty name="page.topDiv"/>
</g:if>
<g:else>
<div>Default text/html here</div>
</g:else>
The default content could also live in an external template gsp. The render method could then be used to display that content in the default attribute of g:pageProperty:
<g:pageProperty name="page.topDiv" default="${render(template:'topDiv')}"/>
Where in this case, the default content would be located in _topDiv.gsp.
I think you can try instead.
<g:render template=""><g:render>
加载中,请稍侯......
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