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<p class='location'>Trait Cast</p><div class="block items"><a class="sidebar-title" href="#provided-methods">Provided Methods</a><div class="sidebar-links"><a href="#method.upcast">upcast</a><a href="#method.downcast">downcast</a><a href="#method.is">is</a><a href="#method.dynamic_cast">dynamic_cast</a></div><a class="sidebar-title" href="#implementors">Implementors</a></div><p class='location'><a href='../index.html'>glib</a>::<wbr><a href='index.html'>object</a></p><script>window.sidebarCurrent = {name: 'Cast', ty: 'trait', relpath: ''};</script><script defer src="sidebar-items.js"></script>
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<h1 class='fqn'><span class='in-band'>Trait <a href='../index.html'>glib</a>::<wbr><a href='index.html'>object</a>::<wbr><a class="trait" href=''>Cast</a></span><span class='out-of-band'><span id='render-detail'>
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</span><a class='srclink' href='../../src/glib/object.rs.html#25-103' title='goto source code'>[src]</a></span></h1>
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<pre class='rust trait'>pub trait Cast: <a class="trait" href="../../glib/object/trait.IsA.html" title="trait glib::object::IsA">IsA</a><<a class="struct" href="../../glib/object/struct.Object.html" title="struct glib::object::Object">Object</a>> {
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fn <a href='#method.upcast' class='fnname'>upcast</a><T>(self) -> T<br> <span class="where">where<br> T: <a class="trait" href="../../glib/types/trait.StaticType.html" title="trait glib::types::StaticType">StaticType</a> + <a class="trait" href="../../glib/wrapper/trait.UnsafeFrom.html" title="trait glib::wrapper::UnsafeFrom">UnsafeFrom</a><ObjectRef> + <a class="trait" href="../../glib/wrapper/trait.Wrapper.html" title="trait glib::wrapper::Wrapper">Wrapper</a>,<br> Self: <a class="trait" href="../../glib/object/trait.IsA.html" title="trait glib::object::IsA">IsA</a><T></span>,
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{ ... }
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<div class='item-spacer'></div> fn <a href='#method.downcast' class='fnname'>downcast</a><T>(self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, Self><br> <span class="where">where<br> Self: <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="../../glib/object/trait.Downcast.html" title="trait glib::object::Downcast">Downcast</a><T></span>,
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{ ... }
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<div class='item-spacer'></div> fn <a href='#method.is' class='fnname'>is</a><T>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a><br> <span class="where">where<br> T: <a class="trait" href="../../glib/types/trait.StaticType.html" title="trait glib::types::StaticType">StaticType</a></span>,
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{ ... }
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<div class='item-spacer'></div> fn <a href='#method.dynamic_cast' class='fnname'>dynamic_cast</a><T>(self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, Self><br> <span class="where">where<br> T: <a class="trait" href="../../glib/types/trait.StaticType.html" title="trait glib::types::StaticType">StaticType</a> + <a class="trait" href="../../glib/wrapper/trait.UnsafeFrom.html" title="trait glib::wrapper::UnsafeFrom">UnsafeFrom</a><ObjectRef> + <a class="trait" href="../../glib/wrapper/trait.Wrapper.html" title="trait glib::wrapper::Wrapper">Wrapper</a></span>,
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{ ... }
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}</pre><div class='docblock'><p>Upcasting and downcasting support.</p>
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<p>Provides conversions up and down the class hierarchy tree.</p>
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</div>
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<h2 id='provided-methods' class='small-section-header'>
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Provided Methods<a href='#provided-methods' class='anchor'></a>
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</h2>
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<div class='methods'>
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<h3 id='method.upcast' class='method'><span id='upcast.v' class='invisible'><code>fn <a href='#method.upcast' class='fnname'>upcast</a><T>(self) -> T <span class="where fmt-newline">where<br> T: <a class="trait" href="../../glib/types/trait.StaticType.html" title="trait glib::types::StaticType">StaticType</a> + <a class="trait" href="../../glib/wrapper/trait.UnsafeFrom.html" title="trait glib::wrapper::UnsafeFrom">UnsafeFrom</a><ObjectRef> + <a class="trait" href="../../glib/wrapper/trait.Wrapper.html" title="trait glib::wrapper::Wrapper">Wrapper</a>,<br> Self: <a class="trait" href="../../glib/object/trait.IsA.html" title="trait glib::object::IsA">IsA</a><T>, </span></code></span></h3><div class='docblock'><p>Upcasts an object to a superclass or interface <code>T</code>.</p>
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<p><em>NOTE</em>: This statically checks at compile-time if casting is possible. It is not always
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known at compile-time, whether a specific object implements an interface or not, in which case
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<code>upcast</code> would fail to compile. <code>dynamic_cast</code> can be used in these circumstances, which
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is checking the types at runtime.</p>
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<h1 id='example' class='section-header'><a href='#example'>Example</a></h1>
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<div class='information'><div class='tooltip ignore'>ⓘ<span class='tooltiptext'>This example is not tested</span></div></div><pre class="rust rust-example-rendered ignore">
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<span class="kw">let</span> <span class="ident">button</span> <span class="op">=</span> <span class="ident">gtk</span>::<span class="ident">Button</span>::<span class="ident">new</span>();
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<span class="kw">let</span> <span class="ident">widget</span> <span class="op">=</span> <span class="ident">button</span>.<span class="ident">upcast</span>::<span class="op"><</span><span class="ident">gtk</span>::<span class="ident">Widget</span><span class="op">></span>();</pre>
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</div><h3 id='method.downcast' class='method'><span id='downcast.v' class='invisible'><code>fn <a href='#method.downcast' class='fnname'>downcast</a><T>(self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, Self> <span class="where fmt-newline">where<br> Self: <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="../../glib/object/trait.Downcast.html" title="trait glib::object::Downcast">Downcast</a><T>, </span></code></span></h3><div class='docblock'><p>Tries to downcast to a subclass or interface implementor <code>T</code>.</p>
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<p>Returns <code>Ok(T)</code> if the object is an instance of <code>T</code> and <code>Err(self)</code>
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otherwise.</p>
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<p><em>NOTE</em>: This statically checks at compile-time if casting is possible. It is not always
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known at compile-time, whether a specific object implements an interface or not, in which case
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<code>upcast</code> would fail to compile. <code>dynamic_cast</code> can be used in these circumstances, which
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is checking the types at runtime.</p>
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<h1 id='example-1' class='section-header'><a href='#example-1'>Example</a></h1>
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<div class='information'><div class='tooltip ignore'>ⓘ<span class='tooltiptext'>This example is not tested</span></div></div><pre class="rust rust-example-rendered ignore">
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<span class="kw">let</span> <span class="ident">button</span> <span class="op">=</span> <span class="ident">gtk</span>::<span class="ident">Button</span>::<span class="ident">new</span>();
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<span class="kw">let</span> <span class="ident">widget</span> <span class="op">=</span> <span class="ident">button</span>.<span class="ident">upcast</span>::<span class="op"><</span><span class="ident">gtk</span>::<span class="ident">Widget</span><span class="op">></span>();
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<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">widget</span>.<span class="ident">downcast</span>::<span class="op"><</span><span class="ident">gtk</span>::<span class="ident">Button</span><span class="op">></span>().<span class="ident">is_ok</span>());</pre>
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</div><h3 id='method.is' class='method'><span id='is.v' class='invisible'><code>fn <a href='#method.is' class='fnname'>is</a><T>(&self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../glib/types/trait.StaticType.html" title="trait glib::types::StaticType">StaticType</a>, </span></code></span></h3><div class='docblock'><p>Returns <code>true</code> if the object is an instance of (can be cast to) <code>T</code>.</p>
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</div><h3 id='method.dynamic_cast' class='method'><span id='dynamic_cast.v' class='invisible'><code>fn <a href='#method.dynamic_cast' class='fnname'>dynamic_cast</a><T>(self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, Self> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../glib/types/trait.StaticType.html" title="trait glib::types::StaticType">StaticType</a> + <a class="trait" href="../../glib/wrapper/trait.UnsafeFrom.html" title="trait glib::wrapper::UnsafeFrom">UnsafeFrom</a><ObjectRef> + <a class="trait" href="../../glib/wrapper/trait.Wrapper.html" title="trait glib::wrapper::Wrapper">Wrapper</a>, </span></code></span></h3><div class='docblock'><p>Tries to cast to an object of type <code>T</code>. This handles upcasting, downcasting
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and casting between interface and interface implementors. All checks are performed at
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runtime, while <code>downcast</code> and <code>upcast</code> will do many checks at compile-time already.</p>
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<p>It is not always known at compile-time, whether a specific object implements an interface or
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not, and checking as to be performed at runtime.</p>
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<p>Returns <code>Ok(T)</code> if the object is an instance of <code>T</code> and <code>Err(self)</code>
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otherwise.</p>
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<h1 id='example-2' class='section-header'><a href='#example-2'>Example</a></h1>
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<div class='information'><div class='tooltip ignore'>ⓘ<span class='tooltiptext'>This example is not tested</span></div></div><pre class="rust rust-example-rendered ignore">
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<span class="kw">let</span> <span class="ident">button</span> <span class="op">=</span> <span class="ident">gtk</span>::<span class="ident">Button</span>::<span class="ident">new</span>();
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<span class="kw">let</span> <span class="ident">widget</span> <span class="op">=</span> <span class="ident">button</span>.<span class="ident">dynamic_cast</span>::<span class="op"><</span><span class="ident">gtk</span>::<span class="ident">Widget</span><span class="op">></span>();
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<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">widget</span>.<span class="ident">is_ok</span>);
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<span class="kw">let</span> <span class="ident">widget</span> <span class="op">=</span> <span class="ident">widget</span>.<span class="ident">unwrap</span>();
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<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">widget</span>.<span class="ident">dynamic_cast</span>::<span class="op"><</span><span class="ident">gtk</span>::<span class="ident">Button</span><span class="op">></span>().<span class="ident">is_ok</span>());</pre>
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