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<td >Qt 5.9</td><td ><a href="qtqml-index.html">Qt QML</a></td><td ><a href="qtqml-qmlmodule.html">QML Types</a></td><td >Connections QML Type</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right">Qt 5.9.4 Reference Documentation</td>
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<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#properties">Properties</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
</ul>
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<h1 class="title">Connections QML Type</h1>
<span class="subtitle"></span>
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<p>Describes generalized connections to signals <a href="#details">More...</a></p>
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<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> Import Statement:</td><td class="memItemRight bottomAlign"> import QtQml 2.2</td></tr></table></div><ul>
<li><a href="qml-qtqml-connections-members.html">List of all members, including inherited members</a></li>
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<a name="properties"></a>
<h2 id="properties">Properties</h2>
<ul>
<li class="fn"><b><b><a href="qml-qtqml-connections.html#enabled-prop">enabled</a></b></b> : bool</li>
<li class="fn"><b><b><a href="qml-qtqml-connections.html#ignoreUnknownSignals-prop">ignoreUnknownSignals</a></b></b> : bool</li>
<li class="fn"><b><b><a href="qml-qtqml-connections.html#target-prop">target</a></b></b> : Object</li>
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<a name="details"></a>
<h2 id="details">Detailed Description</h2>
<p>A Connections object creates a connection to a QML signal.</p>
<p>When connecting to signals in QML, the usual way is to create an "on<Signal>" handler that reacts when a signal is received, like this:</p>
<pre class="qml">
<span class="type">MouseArea</span> {
<span class="name">onClicked</span>: { <span class="name">foo</span>(<span class="name">parameters</span>) }
}
</pre>
<p>However, it is not possible to connect to a signal in this way in some cases, such as when:</p>
<ul>
<li>Multiple connections to the same signal are required</li>
<li>Creating connections outside the scope of the signal sender</li>
<li>Connecting to targets not defined in QML</li>
</ul>
<p>When any of these are needed, the Connections type can be used instead.</p>
<p>For example, the above code can be changed to use a Connections object, like this:</p>
<pre class="qml">
<span class="type">MouseArea</span> {
<span class="type"><a href="qml-qtqml-connections.html">Connections</a></span> {
<span class="name">onClicked</span>: <span class="name">foo</span>(<span class="name">parameters</span>)
}
}
</pre>
<p>More generally, the Connections object can be a child of some object other than the sender of the signal:</p>
<pre class="qml">
<span class="type">MouseArea</span> {
<span class="name">id</span>: <span class="name">area</span>
}
<span class="comment">// ...</span>
</pre>
<pre class="qml">
<span class="type"><a href="qml-qtqml-connections.html">Connections</a></span> {
<span class="name">target</span>: <span class="name">area</span>
<span class="name">onClicked</span>: <span class="name">foo</span>(<span class="name">parameters</span>)
}
</pre>
<p><b>See also </b><a href="qtqml-index.html">Qt QML</a>.</p>
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<h2>Property Documentation</h2>
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<td class="tblQmlPropNode"><p>
<a name="enabled-prop"></a><span class="name">enabled</span> : <span class="type">bool</span></p></td></tr>
</table></div>
</div><div class="qmldoc"><p>This property holds whether the item accepts change events.</p>
<p>By default, this property is <code>true</code>.</p>
<p>This QML property was introduced in Qt 5.7.</p>
</div></div><!-- @@@enabled -->
<br/>
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<tr valign="top" class="odd" id="ignoreUnknownSignals-prop">
<td class="tblQmlPropNode"><p>
<a name="ignoreUnknownSignals-prop"></a><span class="name">ignoreUnknownSignals</span> : <span class="type">bool</span></p></td></tr>
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</div><div class="qmldoc"><p>Normally, a connection to a non-existent signal produces runtime errors.</p>
<p>If this property is set to <code>true</code>, such errors are ignored. This is useful if you intend to connect to different types of objects, handling a different set of signals for each object.</p>
</div></div><!-- @@@ignoreUnknownSignals -->
<br/>
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<div class="qmlitem"><div class="qmlproto">
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<tr valign="top" class="odd" id="target-prop">
<td class="tblQmlPropNode"><p>
<a name="target-prop"></a><span class="name">target</span> : <span class="type">Object</span></p></td></tr>
</table></div>
</div><div class="qmldoc"><p>This property holds the object that sends the signal.</p>
<p>If this property is not set, the <code>target</code> defaults to the parent of the Connection.</p>
<p>If set to null, no connection is made and any signal handlers are ignored until the target is not null.</p>
</div></div><!-- @@@target -->
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