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Last modified by Pascal Robert on 2012/01/30 22:06
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Pascal Robert 8.1 1 [[WOComponentContent>>url:http://wocommunity.org/documents/javadoc/WebObjects/5.4.2/com/webobjects/directtoweb/generation/WOComponentContentGeneration.html||shape="rect"]] is the standard WebObjects dynamic element used to allow a sub-component to obtain content from its parent component. It acts as a marker in a sub-component to indicate where that content should be rendered. The content itself is the fragment between the child's opening and closing tags in the parent. For example, consider the following pair of components:
Paul Hoadley 6.1 2
Pascal Robert 9.1 3 {{code 0="xml" title="Parent"}}
Paul Hoadley 6.1 4 <div>
5 <wo:Child><em>Hello, World!</em></wo:Child>
6 </div>
Pascal Robert 8.1 7 {{/code}}
Paul Hoadley 6.1 8
Pascal Robert 9.1 9 {{code 0="xml" title="Child"}}
Paul Hoadley 6.1 10
11 <p>
12 <wo:WOComponentContent />
13 </p>
14
15 {{/code}}
16
Pascal Robert 8.1 17 At run-time, the content between {{code language="none"}}<wo:Child>{{/code}} and {{code language="none"}}</wo:Child>{{/code}} is passed to {{code language="none"}}Child{{/code}} and rendered in place of the {{code language="none"}}WOComponentContent{{/code}} element:
Paul Hoadley 6.1 18
Pascal Robert 9.1 19 {{code 0="xml" title="Output"}}
Paul Hoadley 6.1 20
21 <div>
22 <p>
23 <em>Hello, World!</em>
24 </p>
25 </div>
26
27 {{/code}}
28
Pascal Robert 8.1 29 The documentation for {{code language="none"}}WOComponentContent{{/code}} clearly describes its main limitation:
Paul Hoadley 6.1 30
Pascal Robert 8.1 31 >Note: You can only have one WOComponentContent element in a given component.
Paul Hoadley 6.1 32
Pascal Robert 8.1 33 We can overcome this limitation with [[ERXWOComponentContent>>url:http://wocommunity.org/wonder/latest/api/er/extensions/components/ERXWOComponentContent.html||shape="rect"]] and [[ERXWOTemplate>>url:http://wocommunity.org/wonder/latest/api/er/extensions/components/conditionals/ERXWOTemplate.html||shape="rect"]]. Firstly, the child component defines any number of regions for content from the parent using {{code language="none"}}ERXWOComponentContent{{/code}}:
Paul Hoadley 6.1 34
Pascal Robert 9.1 35 {{code 0="xml" title="Child"}}
Paul Hoadley 6.1 36
37 <wo:ERXWOComponentContent templateName="first">
38 First default
39 </wo:ERXWOComponentContent><br/>
40 <wo:ERXWOComponentContent templateName="third">
41 Third default
42 </wo:ERXWOComponentContent><br/>
43 <wo:ERXWOComponentContent templateName="second">
44 Second default
45 </wo:ERXWOComponentContent>
46
47 {{/code}}
48
Pascal Robert 8.1 49 The value for the {{code language="none"}}templateName{{/code}} binding is arbitrary, and we use it to match the {{code language="none"}}ERXWOComponentContent{{/code}} with its {{code language="none"}}ERXWOTemplate{{/code}}.
Paul Hoadley 6.1 50
Pascal Robert 9.1 51 {{code 0="xml" title="Parent"}}
Paul Hoadley 6.1 52
53 <div>
54 <wo:Child>
55 <wo:ERXWOTemplate templateName="third">
56 Some <em>stuff</em> in the third template.
57 </wo:ERXWOTemplate>
58 <wo:ERXWOTemplate templateName="first">
59 Some <em>stuff</em> in the first template.
60 </wo:ERXWOTemplate>
61 </wo:Child>
62 </div>
63
64 {{/code}}
65
Pascal Robert 8.1 66 Note that the order of the {{code language="none"}}ERXWOTemplate{{/code}} components in the parent need not match the order of the {{code language="none"}}ERXWOComponentContent{{/code}} elements in the child (they are matched on the {{code language="none"}}templateName{{/code}} binding), and if the child finds no matching {{code language="none"}}ERXWOTemplate{{/code}}, the content within the {{code language="none"}}ERXWOComponentContent{{/code}} element itself is rendered to the output. In this example, the output would be:
Paul Hoadley 6.1 67
Pascal Robert 9.1 68 {{code 0="xml" title="Output"}}
Paul Hoadley 6.1 69
70 <div>
71 Some <em>stuff</em> in the first template.
72 Some <em>stuff</em> in the third template.
73 Second default
74 </div>
75
76 {{/code}}