1

I am trying to get sObject fields name in 2nd pick list on the basis of selected object name in 1st pick list.

Here is my class..

public with sharing class ExtractSobject{
    public list<SelectOption> fields { get; set; }

    public String objectName { get; set; }    

    public List<SelectOption> getSelectedobjnames()
      {
        List<Schema.SObjectType> obj = Schema.getGlobalDescribe().Values();
         List<SelectOption> options = new List<SelectOption>();
           options.add(new SelectOption('--Select Object--','--Select Object--'));
            for(Schema.SObjectType st : obj)
              {
               options.add(new SelectOption(st.getDescribe().getName(),st.getDescribe().getName()));
              }
               return options;
       }
         public String Sf{get;set;}
         public List<SelectOption> objFields{get; set;}

         public List<SelectOption> getSelectedobjFields()
      {
        SObjectType objTyp = Schema.getGlobalDescribe().get('Selectedobjnames');
        DescribeSObjectResult objDef = objTyp.getDescribe();
        Map<String, SObjectField> fields = objDef.fields.getMap();

        Set<String> fieldSet = fields.keySet();
        List<SelectOption> options = new List<SelectOption>();
        options.add(new SelectOption('--Select Object--','--Select Object--'));
          for(String s:fieldSet)
             {  
              SObjectField Sobjfields = fields.get(s);
              DescribeFieldResult selectedField = Sobjfields.getDescribe();                 
              options.add(new SelectOption(selectedField.getName(),selectedField.getName()));
              }
         return options;
       }
}

Page...

<apex:page controller="ExtractSobject">
<apex:form >
   <apex:pageblock >
     <apex:pageblocksection >
       <apex:pageBlockSectionItem >
         <apex:outputlabel value="Select Object"/>
          <apex:selectList value="{!fields}" size="1">
            <apex:selectoptions value="{!Selectedobjnames}"></apex:selectoptions>
            <apex:actionSupport event="onchange" rerender="a"/>
         </apex:selectList>
       </apex:pageBlockSectionItem>

     <apex:pageBlockSectionItem >
      <apex:outputPanel id="a">
         <apex:outputLabel value="Object Fields" ></apex:outputLabel>
             <apex:selectList value="{!Sf}" size="1"> 
                   <apex:selectOptions value="{!SelectedobjFields}" />
             </apex:selectList>
      </apex:outputPanel>
     </apex:pageBlockSectionItem>


   </apex:pageBlockSection>   
  </apex:pageblock>
 </apex:form>

</apex:page>

I am getting an exception

Attempt to de-reference a null object

  • Is selectedobjnames literally the name of the object you're trying to describe? That would cause a NullPointerException. – sfdcfox Jul 28 '15 at 5:02
  • Actually selectedobjnames is not an object it is the name of function which store all sobject name in pick-list... – Ankita Dhamgaya Jul 28 '15 at 5:04
  • your code's Schema.getGlobalDescribe().get('Selectedobjnames') this line return null that's why you are facing this error. you have to specify object name in get method.. – Amit Chaudhary Jul 28 '15 at 6:27
2

In this line

 SObjectType objTyp = Schema.getGlobalDescribe().get('Selectedobjnames');
 DescribeSObjectResult objDef = objTyp.getDescribe();

You are giving 'Selectedobjnames' as a string. you need to pass it without single quote. I think it will solve your problem.

| improve this answer | |
  • Because there is NO OBJECT NAMED SelectedObjNames – Eric Jul 28 '15 at 14:07
1

Seems time-consuming for us to read through the code and locate the issue. So instead, I will provide you some info on how to debug this one.

For VF page, enable development mode for your current user: How to enable development mode. Refresh your page. Now you should get the detailed stack trace. That would hopefully help you resolving your issue

| improve this answer | |
0

As a start

You cannot use the selected objectnames in your code as a value as the getter always return a new list.

Based on how you currently have you will need to use the property in your controller you already have objectName:

SObjectType objTyp = Schema.getGlobalDescribe().get(objectName);

Then change your VF page with this:

<apex:selectList value="{!objectName}" size="1">
            <apex:selectoptions value="{!Selectedobjnames}"></apex:selectoptions>
            <apex:actionSupport event="onchange" rerender="a"/>
         </apex:selectList>
| improve this answer | |
  • Thank you Eric but still getting the same exception.. – Ankita Dhamgaya Jul 28 '15 at 5:55
  • then objectName is not being populated. – Eric Jul 28 '15 at 14:05

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.