I've got quite a challenge while working with null values and a wrapper.

I query the database which sometimes might have null values, but when trying to create a new record (or actually assigning variables) I get exception. Code below.

  List<electricity_meter__c> MeterList = [SELECT Day_rate__c,Standing_Charge_yr__c 
                                          FROM ...]; 
  WrapperList = New List<WrapperClassEx>();
  for(electricity_meter__c met: MeterList){
      double currentStandingCharge = new double();
      if(met.get('Standing_Charge_yr__c')!=null){
          double currentStandingCharge = double.valueOf( met.get('Standing_Charge_yr__c') );
      } else {
          double currentStandingCharge = 0;
  }                    
  double currentDayRate = double.valueOf( met.get('Day_rate__c') );  
  WrapperList.add(New WrapperClassEx(currentDayRate,currentStandingCharge));

  for (WrapperClassEx wrap : WrapperList){
      lineItems.add(new Line_Items__c(                
          Current_Day_Rate__c=decimal.valueOf( wrap.currentDayRate ), 
          Current_Standing_Charge__c=decimal.valueOf(wrap.currentStanding)
      ));
  } 

If I leave code like this, I get Duplicate variable: currentStandingCharge (attempting to re-create the variable with type: double).

If I remove line double currentStandingCharge = new double();, I get Variable does not exist: currentStandingCharge.

If I remove the if() I get Argument 1 cannot be null Error is in expression '{!save}' in component <apex:commandButton> in page ... which by trial and error I found to be issue with adding fields to Line Items (last 4 lines in code excerpt).

I guess I am missing something really simple, just don't know what.

Any ideas?

Attribution to: dzh

Possible Suggestion/Solution #1

Remove the word double You already declared these variables... so you don't want to redeclare them.

if(met.get('Standing_Charge_yr__c')!=null){
    double currentStandingCharge = double.valueOf( met.get('Standing_Charge_yr__c') );
} else {
    double currentStandingCharge = 0;
} 

Attribution to: dphil
This content is remixed from stackoverflow or stackexchange. Please visit https://salesforce.stackexchange.com/questions/32771