how to concat a variable to a regex in C# : <p>I am trying to concat a variable to a regen in c# but it is not working</p>

<pre><code>string color_id = "sdsdssd";
Match variations = Regex.Match (data, @""+color_id+"_[^\""]*\""\W\,\""sizes\""\:\s*\W.*?businessCatalogItemId"":\"")", RegexOptions.IgnoreCase);@""+color_id+"_[^\""]*\""\W\,\""sizes\""\:\s*\W.*?businessCatalogItemId"":\"")";
</code></pre>

<p>But the above is not working</p>

<p>How to concat a variable at starting element to regex in c#</p>
