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| <title>Hidden</title> |
| <link rel="stylesheet" type="text/css" href="Tapestry.css" title="style"> |
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| <table border="0" cellpadding="4" cellspacing="4" width="100%"> |
| |
| <tr valign="top"> |
| <td> |
| <table> |
| <tr> |
| <td><font size="+2"><b>Hidden</b></font></td> |
| </tr> |
| <tr> |
| <td> |
| <A href="../api/org/apache/tapestry/form/Hidden.html"> |
| org.apache.tapestry.form.Hidden</a> |
| </td> |
| </tr> |
| </table> |
| </td> |
| <td> |
| <table align="right" valign="middle" bgcolor="#c0c0c0" cellpadding="8"> |
| <tr> |
| <td>Non Visual Component</td> |
| </tr> |
| </table> |
| </td> |
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| <tr valign="center"> |
| <td colspan="2"> </td> |
| </tr> |
| |
| <tr> |
| <td colspan="2"> |
| <b>Description</b> |
| <br> |
| Adds a hidden HTML <input type="hidden"> field to a <A href="Form.html"> |
| Form</a>. This is often used to |
| synchronize data when the |
| form is submitted with values known when the page was rendered. |
| </td> |
| </tr> |
| |
| <tr> |
| <td colspan="2"> |
| <b>See Also</b> |
| <br> |
| <A href="Form.html">Form</a>, |
| <A href="ListEdit.html">ListEdit</a> |
| </td> |
| </tr> |
| |
| <tr> |
| <td colspan="2"> |
| <b>Parameters</b> |
| <br> |
| <table border="1" cellpadding="4" cellspacing="4" class="parameters"> |
| <tr> |
| <th>Name</th> |
| <th>Type</th> |
| <th>Direction</th> |
| <th>Required</th> |
| <th>Default</th> |
| <th>Description</th> |
| </tr> |
| <tr> |
| <td>value</td> |
| <td>Object</td> |
| <td>in/out</td> |
| <td>yes</td> |
| <td> </td> |
| <td>The value to be stored in the the hidden field. The parameter is read |
| when the HTML response is generated, and then written when the form is |
| submitted. A <A href="../api/org/apache/tapestry/util/io/DataSqueezer.html"><tt> |
| DataSqueezer</tt></a> is used to convert the value between an arbitrary type |
| and a String. |
| </td> |
| </tr> |
| <tr> |
| <td>id</td> |
| <td>Object</td> |
| <td>in</td> |
| <td>no</td> |
| <td>undefined in HTML presentation.</td> |
| <td>ID parameter of HTML hidden object. The parameter is read when |
| the HTML response is generated and if there is a specific value the component generate parameter id with passed value in its HTML presentation.</td> |
| </tr> |
| <tr> |
| <td>listener</td> |
| <td><A href="../api/org/apache/tapestry/IActionListener.html"> |
| <tt>IActionListener</tt></a> |
| </td> |
| <td>in</td> |
| <td>no</td> |
| <td> </td> |
| <td> |
| A listener that is informed after the value parameter is updated. This |
| allows the data set operated on by the rest of the |
| <A href="Form.html">Form</a> components to be synchronized to the value |
| stored in the hidden field. |
| <p> |
| A typical use is to encode the primary key of an entity as a Hidden; when |
| the form is submitted, the Hidden's listener re-reads the corresponding |
| entity from the database. |
| </td> |
| </tr> |
| <tr> |
| <td>encode</td> |
| <td>boolean</td> |
| <td>in</td> |
| <td>no</td> |
| <td>true</td> |
| <td> |
| If true (the default) a |
| <a href="../api/org/apache/tapestry/util/io/DataSqueezer.html"><tt>DataSqueezer</tt></a> |
| is used to transform the value Object into the HTML value string, and (on submit) |
| to convert the string back into an Object. |
| |
| <p> |
| If false, then the value must be a String. This is most likely used |
| when the hidden field is used to communicate with client-side logic in JavaScript |
| (which is not able to interpret even Strings encoded by DataSqueezer). If you find |
| yourself getting strange errors during the form rewind it could easily be |
| Tapestry trying to interpret a value you've set via Javascript. |
| </td> |
| </tr> |
| </table> |
| <P>Body: <STRONG>removed</STRONG><BR> |
| Informal parameters: <STRONG>forbidden</STRONG><br> |
| Reserved parameters: "name" |
| </P> |
| </td> |
| </tr> |
| |
| <tr> |
| <td colspan="2"> |
| <b>Examples</b> |
| <p> |
| This example is under construction. |
| </p> |
| |
| </td></tr> |
| |
| </table> |
| </td></tr> |
| <tr> |
| <td colspan="3"><hr></td> |
| </tr> |
| <tr> |
| <td align="left"><A href="GenericLink.html"><IMG alt=GenericLink src="common-images/prev.png"></a></td> |
| <td align="middle"><A href="index.html"><IMG alt="Component Index" src="common-images/home.png" ></a></td> |
| <td align="right"><A href="Image.html"><IMG alt=Image src="common-images/next.png"></a></td> |
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