how i un-escape xml entities simply .net

i have formula advantage innerxml xmlnode.

the node enclose only calm (with html) xml.

for example:

<xmlnode>
    here &lt;strong&gt;html&lt;/strong&gt;
<xmlnode>

or

<xmlnode>
    <xmlcontent>here content</xmlcontnet>
</xmlnode>

if i innerxml <xmlnode> html tags returned xml entities.

i can't innertext since i need means xml contents. i unequivocally need proceed un-escape html tags, since i detect it's xml act accordingly.

i speculation i htmldecode, nonetheless decode xml encoded entities?

update: i speculation i'm careless bit above here simplified scenario:

i have xml request looks this:

<content id="1">
    <data>&lt;p&gt;a test&lt;/p&gt;</data>
</content id="2">
<content>
    <data>
        <dataitem>a test</dataitem>
    </data>
</content>

if i do:

xmlnode xn1 = document.selectsinglenode("/content[@id=1]/data");
xmlnode xn2 = document.selectsinglenode("/content[@id=2]/data");

console.writeline(xn1.innerxml);
console.writeline(xn2.innerxml);    

xn1 relapse

 <p>a test</p>

xn2 relapse <dataitem>a test</dataitem>

i am already checking returned xml (in box xn2) i need un-escape < etc xn1.

htmldecode does this, nonetheless i'm certain work everything. doubt stays htmldecode hoop illusory entities there category somewhere me.