Get a value from an inputfield into a controller extension SOQL

Question

Hi all i am trying to access the inputfield value that the user selects and then pass it to an SOQL query in my controller extension then return the SOQL result to an outputText compunent, my code is shown below:

Visualforce

<apex:page standardController="Ships_Book__c" extensions="sBookController">
    <apex:pageBlock title="Ships Book">
        <apex:pageBlockSection >
            <apex:form >
                <apex:inputField value="{!Ships_Book__c.Vessel_Name__c}" id="Vessel_Name">
                    <apex:actionSupport event="onchange" action="{!setsWeight}"/>
                </apex:inputField>
                Vessel Weight&nbsp; &nbsp; &nbsp;
                   <apex:outputText value="{0}">
                        <apex:param value="{!sWeight}"/>
                    </apex:outputText>
            </apex:form>
        </apex:pageBlockSection>
    </apex:pageBlock>
</apex:page>

Apex

public class sBookController {

    private ApexPages.StandardController stdCtrl {get; Set;}

    public integer sWeight;

    public sBookController(ApexPages.StandardController std) {
        stdCtrl = std;        
    }

    public integer getsWeight() {
        return sWeight;
    }

    public void setsWeight() {

        sWeight= [SELECT Vessel_weight__C FROM Vessel_Weight__c WHERE Vessel_Name__c =: ship.Vessel_Name__c Limit 1];
    }
}

Any help would be greatly appreciated as i am just learning

Thanks

Answer 1

You need to get the standard record associated with the ApexPages.StandardController and then use that record in the SOQL.

public class sBookController {

    private Ships_Book__c ship {get; set;}
    public integer sWeight;

    public sBookController(ApexPages.StandardController std) {        
        ship = (Ships_Book__c)stdCtrl.getRecord();
    }

    public integer getsWeight() {
        return sWeight;
    }

    public void setsWeight() {      
        List<Vessel_Weight__c> lstVesselWeight = [SELECT Vessel_weight__C FROM Vessel_Weight__c WHERE Vessel_Name__c =: ship.Vessel_Name__c Limit 1];
        if(!lstVesselWeight,isEmpty())
            sWeight = lstVesselWeight[0].Vessel_weight__C;
    }
}

Note:

1. I removed the ApexPages.StandardController and created a object for Ships_Book__c
2. Instead of assigning the query to the integer directly, i assigned it to the list, check for not empty and assign the value to integer.

Hope it helps.