How to use 'choose ... when ..." policy statements to control execution flows?

If you want to control execution flows in Azure API management process, you can use the 'choose ... when ..." policy statement.

The "choose ... when ..." statement has the following syntax:

<choose>   
    <when condition="Boolean_expression">   
        ...
    </when>   
    <when condition="Boolean_expression">   
        ...
    </when>   
    <otherwise>   
        ...
    </otherwise>   
</choose>  

For example,

<choose>  
	<when condition="@(context.Variables.GetValueOrDefault&lt;bool>("isMobile"))">  
		<set-query-parameter name="mobile" exists-action="override">  
			<value>true</value>  
		</set-query-parameter>  
	</when>  
	<otherwise>  
		<set-query-parameter name="mobile" exists-action="override">  
			<value>false</value>  
		</set-query-parameter>  
	</otherwise>  
</choose>  

⇒Using Azure API Policy

⇒⇒Microsoft Azure API Management Tutorials