IF condition with OR statement for rendering page is not working

Question

Controller:
...
public boolean Closebutton {
    get {
        if(Opp.Status != 'Closed Lost' || Opp.Status != 'Closed Won')
        {
            return true;
        }
        return false;
    }
    Set;      
}
...

Page:
...
<apex:commandButton value="Close Opportunity" action="{!CloseOpp}" rendered="{!Closebutton}"/>

If I state any one condition or many conditions with AND statement, the button is obeying the condition and appearing/disappearing in the page. But when I state multiple conditions with ||, the button always appear on the page. Any idea?

Answer 1

I think there is logical error in your IF condition.

It will always return TRUE

Say if Opp.Status is set to 'Closed Lost' then FIRST part of OR will be true and so it will return TRUE

if Opp.Status is set to 'Closed Won' then second part of OR will be true and so it will return TRUE

If Opp.Status is set to 'XYZ' then first part of OR will be true and so it will return TRUE

SO it short it will always return TRUE.

Answer 2

From your advice and suggestions, I'm clear that comparing the same field with two different values in an OR statement will always return TRUE. I've modified the code. and this code is working fine now.

Controller
...
public boolean Closebutton {
    get {
        if(Opp.Status != 'Closed Lost'){ 
            if(Opp.Status != 'Closed Won'){
                return true;
            }
        }
        return false;
    }
    Set;      
}
...

Page
...
<apex:commandButton value="Close Opportunity" action="{!CloseOpp}" rendered="{!Closebutton}"/>
...

Answer 3

You have a space in your rendered attribute. Your boolean condition is looking for "Closed Win" when the standard status is "Closed Won", so that could also be the issue. Furthermore, the rendered attribute does not always render correctly with booleans.

Lastly why not simply compare either the Opp Status or the Opportunity IsClosed field in the rendered attribute, rather than creating a new variable for rendering? See an example below:

rendered="{!NOT(OR(Opp.status == 'Closed Won',Opp.status == 'Closed Lost'))}"

Or

rendered="{!NOT(Opp.IsClosed)}"

Note: You'll have to query for IsClosed if not doing so already.

More info on the Opportunity standard fields here: http://www.salesforce.com/us/developer/docs/api/Content/sforce_api_objects_opportunity.htm