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    <blockquote> <p>My question is, what happens when I set my variable to <strong>null</strong> inside a using block? Will it still get disposed properly?</p> </blockquote> <p>That depends on where your variable's declared. It will either be disposed of correctly, or your code won't compile in the first place.</p> <h1>If your variable is declared outside the using statement: Yes</h1> <pre><code>A a; using (a = new A()) { a = null; } </code></pre> <p>Yes, it will be disposed properly. For a simple test:</p> <p><img src="https://i.stack.imgur.com/mmLnN.png" alt="A variable is nulled within a using block and disposed of successfully"><br> <sup>My text colour scheme is <a href="http://studiostyl.es/schemes/ragnarok-grey" rel="nofollow noreferrer">Ragnarok Grey</a>.</sup></p> <p>Even with the assignment cleared, a reference to the <code>new A()</code> seems to have been maintained. <code>a</code> is disposed of at the end of the <code>using</code> statement as expected, even if it's nulled inside.</p> <p>In some versions of Visual Studio, this may result in <a href="http://msdn.microsoft.com/en-us/library/zhdyhfk6(v=vs.90).aspx" rel="nofollow noreferrer">Compiler Warning (level 2) CS0728</a>:</p> <blockquote> <p>Possibly incorrect assignment to local 'a' which is the argument to a using or lock statement. The Dispose call or unlocking will happen on the original value of the local.</p> </blockquote> <h1>If your variable declared within the using statement: N/A</h1> <pre><code>using (var a = new A()) { a = null; } </code></pre> <p>The above code won't compile. You're not permitted to assign to a <code>using</code> variable in the first place. The above code produces this compile error:</p> <blockquote> <p>Cannot assign to 'a' because it is a 'using variable'</p> </blockquote> <p>This is <a href="http://msdn.microsoft.com/query/dev11.query?appId=Dev11IDEF1&amp;l=EN-US&amp;k=k(CS1656);k(TargetFrameworkMoniker-.NETFramework,Version%3Dv4.5)&amp;rd=true" rel="nofollow noreferrer">Compiler Error CS1656</a>.</p> <blockquote> <p>This error occurs when an assignment to variable occurs in a read-only context. Read-only contexts include <strong>foreach</strong> iteration variables, <strong>using</strong> variables, and fixed variables. To resolve this error, avoid assignments to a statement variable in <strong>using</strong> blocks, <strong>foreach</strong> statements, and <strong>fixed</strong> statements.</p> </blockquote>
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    1. POCan I clear an external variable inside a using block?
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    1. COGood answer. These compiler writers... they're a clever bunch!
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    2. COBut the Op declares logger _before_ the using statement. His code will compile with just a warning.
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      1. USHenk Holterman
    3. CO@Henk Edited. Thanks for pointing this out. I didn't notice that, wow. The two have very different results.
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