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    <p>You will need to add some kind of flag to let the reader know if it should read the next bytes or not.</p> <pre><code>public decimal? ReadNullableDecimal() { bool hasValue = ReadBoolean(); if (hasValue) return ReadDecimal(); return null; } public void Write(decimal? val) { bool hasValue = val.HasValue; Write(hasValue) if(hasValue) Write(val.Value); } </code></pre> <p>However we can be clever and create a generic method that works for all struct based types</p> <pre><code>public Nullable&lt;T&gt; ReadNullable&lt;T&gt;(Func&lt;T&gt; ReadDelegate) where T : struct { bool hasValue = ReadBoolean(); if (hasValue) return ReadDelegate(); return null; } public void Write&lt;T&gt;(Nullable&lt;T&gt; val) where T : struct { bool hasValue = val.HasValue; Write(hasValue) if(hasValue) Write(val.Value); } </code></pre> <p>If I wanted to use my <code>ReadNullable</code> function to read a <code>Int32</code> I would call it like</p> <pre><code>Int32? nullableInt = customBinaryReader.ReadNullable(customBinaryReader.ReadInt32); </code></pre> <p>So it would test if the value exists, then if it does it would then call the passed in function.</p> <hr> <p><strong>EDIT:</strong> After sleeping on it, the <code>Write&lt;T&gt;</code> method may not work like you expect it to. Because <code>T</code> is not a well defined type the only method that could support it would be <code>Write(object)</code> which Binary writer does not support out of the box. <code>ReadNullable&lt;T&gt;</code> will still work, and if you want to use still use <code>Write&lt;T&gt;</code> you will need to make the result of <code>val.Value</code> <a href="http://msdn.microsoft.com/en-us/library/vstudio/dd264741.aspx" rel="nofollow">dynamic</a>. You will need to benchmark to see if there are any performance issues with this.</p> <pre><code>public void Write&lt;T&gt;(Nullable&lt;T&gt; val) where T : struct { bool hasValue = val.HasValue; Write(hasValue) if(hasValue) Write((dynamic)val.Value); } </code></pre>
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    1. PORead/Write a Nullable Type using BinaryReader?
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    1. USScott Chamberlain
    1. USScott Chamberlain
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    1. COIn case the value is null, write a 0 in lieu of the value. When reading, if the value is null, just read the zero and throw it away. That way, you do not need a flag.
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      1. USTarik
    2. COUmm @Tarik, So how do you tell the diffrence between `decimal? foo = 0` and `decimal? foo = null`?
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    3. CORead hasValue boolean. Case True, ReadDecimal and return it. Case hasValue false, ReadDecimal and return null.
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