testUpload

public class testUpload{
    
    public Expense__c exp {get; set;}
    
    public testUpload(){
        exp = [select id, Name, Company__c, Expense_Type__c, Date__c, Total_Amount__c from Expense__c where id =: ApexPages.currentPage().getParameters().get('Id')];
    }
    
    public Attachment attachment {
        get {
            if (attachment == null)
                attachment = new Attachment();
            return attachment;
        }
        set;
    }
    
    public PageReference upload() {
        
        attachment.OwnerId = UserInfo.getUserId();
        attachment.ParentId = exp.id; // the record the file is attached to
        
        try {
            insert attachment;
        } catch (DMLException e) {
            ApexPages.addMessage(new ApexPages.message(ApexPages.severity.ERROR,'Error uploading attachment'));
            return null;
        } finally {
            attachment = new Attachment(); 
        }
        
        ApexPages.addMessage(new ApexPages.message(ApexPages.severity.INFO,'Attachment uploaded successfully'));
        return null;
    }
    
    public List<Attachment> getAttList(){
        List<Attachment> aList = new List<Attachment>();
        
        for(Attachment a: [select id, Name, Body, Description, ParentID, CreatedDate from Attachment where ParentID =: exp.Id ORDER BY CreatedDate DESC]){
           aList.add(a);   
        }
        
        return aList;
    }
    
}