How to append changes to XML file using C# [VS2015]

Question

How to append changes to XML file using C# [VS2015]

  

My XML file is like this.

 

<userSettings>

<Calc.Properties.Settings>

<setting name="WindowTop" serializeAs="String">

<value>240</value>

</setting>

<setting name="TableBackground" serializeAs="String">

<value>Transparent</value>

</setting>

</Calc.Properties.Settings>

</userSettings>

 

I need to add one more child element and sub child element. How to do this ?

 

The final xml file should be like this.

 

<userSettings>

<Calc.Properties.Settings>

<setting name="WindowTop" serializeAs="String">

<value>240</value>

</setting>

<setting name="TableBackground" serializeAs="String">

<value>Transparent</value>

</setting>

<setting name="TableForeground" serializeAs="String">

<value>Opaque</value>

</setting>

</Calc.Properties.Settings>

</userSettings>