[SalesForce] Input field on force.com sites..Update standard object from guest user force.com sites

I want to show opportunity fields on Force.com and also update an opportunity from force.com sites..

When i am using apex:input fields the fields are not showing in input mode.When i use inputtext it works.My problem is about date fields it comes as a inputtext and dateselector doesn't come.

Now i also want to update the opportunity record.I have found that we can't update standard object.I have found one link where it says if you use without sharing then you can update.
Workarounds for Sites page to update standard object?

But i am not able to do it.Please help in this.Its really very urgent for me.

VF page

<apex:page controller="oppDetailUsersCntlr"  showHeader="false" cache="false" >
<apex:form >
 <apex:sectionHeader title="Opportunity" subtitle="Detail"/>
 <apex:pageBlock mode="inlineEdit" rendered="{!editSection}">
     <apex:pageBlockButtons >
         <apex:commandButton value="Save" id="saveButton" action="{!saveOpp}"/>
         <apex:commandButton value="Edit" id="editButton" action="{!editOpp}"/>
     </apex:pageBlockButtons>
     <apex:pageBlockSection columns="2">
         <apex:inputText value="{!opp.name}"/>
         <apex:inputField value="{!opp.closedate}"/>
         <apex:outputField value="{!opp.accountid}"/>
         <apex:inputText value="{!opp.Probability}"/>
      </apex:pageBlockSection>  
</apex:pageblock>
</apex:page>

Controller

public void saveOpp()
{
editSection=false;
saveSection=true;

Opportunity o=new opportunity(id=id);
o.Probability=opp.Probability;
update o;
System.debug('==============oooooooo============'+o);

}

Best Answer

It appears you may not have fully understood what was being conveyed in the post you've cited in your post. A Sites user license does not allow access to standard objects. The post you're referring to was speaking of using a "mirror" object and a trigger to update Opportunity via sites. That page was also discussing the different types of sharing models to use on the controller and what that meant in terms of user permissions.

Without the proper licenses, your Sites users will not be able to make updates directly to the Opportunity object. You'll need to set up a partner portal/community if you want to be able update Opportunity without using a mirrored object and triggers to do it indirectly.