Salesforce VisualPage CommandLink

<apex:page controller="CreateOpportunity_controller" action="{!createOpportunity}">

<apex:form >

<apex:commandLink action="{!redirectToOpportunity}" value="Open Opportunity" rendered="{!displayOppLink}" />

</apex:form>

</apex:page>

• Has to be inside apex:form
• redirectToOpportunity is the function in CreateOpportunity_controller class. This function can use PageReference object for redirection.
• rendered attribute checks for true / false value of displayOppLink. Other option is rendered="{!IF(contains(caseField, "Contact"), true, false)}"