XForms and XPath

XForms 使用 XPath 对数据急性寻址。这个过程被称为绑定。

XForms 绑定

XForms 使用两个部分来定义数据：XForms 模型和 XForms 用户界面。

XForms 模型是针对数据的一个 XML 模板（实例），而 XForms 用户界面是对数据输入和显示的描述。

XForms 使用 XPath 来定义这个两个部分的连接。这被称为绑定（binding）。

XPath

XPath 用于定义 XML 文档的各部分的 W3C 标准语法。

XPath 使用路径表达式来标示 XML 文档中的节点。这些表达式与您在计算机系统中看到的文件路径表达式非常类似。

XPath ɗan ɗauɗi:

/person/fname

ka ɗauɗi ɗan ɗauɗi ɗan ɗauɗi XML ɗan ɗauɗi ɗan ɗauɗi <fname> ɗan ɗauɗi:

<person>
   <fname>David</fname>
   <lname>Smith</lname>
</person>

Na XPath ɗan ɗauɗi ka ɗauɗi ɗauɗi ɗan ɗauɗi XPath ɗan ɗauɗi ɗan ɗauɗi.

Ayya Ref domin girmama

The XForms model is like this:

<instance>
  <person>
    <name>
      <fname/>
      <lname/>
    </name>
  </person>
</instance>

The XForms user interface can be used ref Attribute toBinding <input> Element:

<input ref="name/fname">
<label>First Name</label>
</input>
<input ref="name/lname">
<label>Last Name</label>
</input>

Hanyar tsohon ɗan ɗauɗi, attibuti ref="name/fname" wani ɗan ɗauɗi XPath ɗan ɗauɗi ɗan ɗauɗi ɗan ɗauɗi <fname> ɗan ɗauɗi ɗan ɗauɗi. Wannan ɗan ɗauɗi zai iya ɗan ɗauɗi gida ɗan ɗauɗiBindingsannan daga ɗan yiwa XML ɗan ɗauɗi ɗan ɗauɗi ɗan ɗauɗi (ɗan ɗauɗi) dake ɗauɗi <fname> ɗan ɗauɗi.

XForms ɗauɗiɗa ɗa iya ɗauɗi ɗan yiwa:

<input ref="/person/name/fname">
<label>First Name</label>
</input>

<input ref="/person/name/lname">
<label>Last Name</label>
</input>

In the above example, the forward slash (/) at the beginning of the XPath expression indicates the root of the XML document.

Binding with Bind

The XForms model is like this:

<model>
<instance>
  <person>
    <name>
      <fname/>
      <lname/>
    </name>
  </person>
</instance>
<bind nodeset="/person/name/fname" id="firstname"/>
<bind nodeset="/person/name/lname" id="lastname"/>
</model>

The XForms user interface can be used bind Attribute toBinding <input> Element:

<input bind="firstname">
<label>First Name</label>
</input>
<input bind="lastname">
<label>Last Name</label>
</input>

Why are there two ways to bind input control elements to instance data?

What can I say, when you start using XForms in complex applications, you will find that using bind for binding is a more flexible way to handle multiple form and multiple instance models.