Why do I get "cannot be accessed with an instance reference" when using teststring.Join but not teststring.Split? (c#)
<p>I'm learning c# and there is something I do not understand that I've been unable to find any help about online.</p>

<pre><code>string[] = testarray = { "test1", "test2", "test3" };
teststring = teststring.Join(" ", testarray);
</code></pre>

<p>This fails with the following error message:</p>

<blockquote>
  <p>Member 'string.Join(string, params string[])' cannot be accessed with an instance reference; qualify it with a type name instead.</p>
</blockquote>

<p>It does however work if I change to:</p>

<pre><code>teststring = string.Join(" ", testarray);
</code></pre>

<p>If I however use the function Split as in:</p>

<pre><code>teststring = teststring.Split(new char[] {' '});
</code></pre>

<p>I am no longer getting an error. I assume this has something to do with certain functions of the string class being static and some not, but how can I tell which function is static and which is not? (if this is the reason)</p>

<p>These enforced calling techniques between static / non-static sure is something to get used to.</p>
