无法在salesforce中保存图像

Question

我试着为每个联系人保存并显示一个图像。我在各自的联系人中成功地保存了图像。但是，当我刷新页面时，我所附的照片并没有显示。以下是代码：

    <apex:page standardController="Contact" extensions="photo_attachmentcls">
<apex:pageBlock >
<apex:form >
  <apex:inputFile value="{!attach}" fileName="{!fileName}"></apex:inputFile>
  <apex:commandButton value="Load" action="{!loader}" />
  <apex:actionSupport event="onchange" />
  </apex:form>
  <apex:outputPanel id="iidd1">
<img id="theImage" src="/servlet/servlet.FileDownload?file={!dsa}" width="100" height="100" />
    </apex:outputPanel>
</apex:pageBlock>

</apex:page>

public class photo_attachmentcls {
    public Attachment asd{get;set;}
    public string purl{get;set;}
    public blob attach{get;set;}
    public String fileName{get;set;}
    public Id recId{get;set;} 
    public String dsa {get;set;}
    public photo_attachmentcls(ApexPages.StandardController ctrl) {

           recId = ApexPages.currentPage().getParameters().get('id');
           asd = new Attachment();



    }
    public void loader()
    {

        asd.body = attach;
        asd.Name = fileName;
        asd.ParentId =  recId;
         insert asd;
        system.debug('nnnn'+asd);
        dsa = asd.id;
        system.debug('ddddd'+dsa);

    }    
}

提前谢谢。

Answer 1

当页面加载时，您需要检查该记录的附件是否存在：

public class photo_attachmentcls {

    public Attachment asd{get;set;}
    public string purl{get;set;}
    public blob attach{get;set;}
    public String fileName{get;set;}
    public Id recId{get;set;} 
    public String dsa {get;set;}

    public photo_attachmentcls(ApexPages.StandardController ctrl) {

           recId = ApexPages.currentPage().getParameters().get('id');

           // check if the contact already has an attachment:
           Contact thisRecord = [select id, (Select Id From NotesAndAttachments) from Contact where Id =: recId];
           if(!thisRecord.NotesAndAttachments.isEmpty()){
                dsa = thisRecord.NotesAndAttachments[0].Id;
           } else{
               asd = new Attachment();
           }

    }
    public void loader()
    {

        asd.body = attach;
        asd.Name = fileName;
        asd.ParentId =  recId;
         insert asd;
        system.debug('nnnn'+asd);
        dsa = asd.id;
        system.debug('ddddd'+dsa);

    }    
}

我建议选择更好的变量名，但我认识到这是某种类型的原型。