Salesforce学习之路-developer篇（三）利用Visualforce Page实现页面的动态刷新案例学习

<!--对于单Visualforce Page,所有的Page都必须包含在一个Page内-->
<apex:page controller="SP_FilterConditionPageController">
    <!--from:Visualforce页面的一部分，允许用户输入和提交按钮的表单-->
    <apex:form >
        <!--outputlabel:输入输出字段的标签-->
        <apex:outputlabel value="Site Name" for="siteValue" />
        <!--selectList:选项列表，允许用户选择一个值或多个值-->
        <apex:selectList value="{!siteName}" size="1" id="siteValue" multiselect="false">
            <!--selectOptions:作为selectList的子组件，提供选择对象的集合-->
            <apex:selectOptions value="{!siteItems}"/>
        </apex:selectList>
        <apex:outputlabel value="Display Months" for="values2" />
        <apex:selectList value="{!displayMonth}" size="1" id="values2" multiselect="false">
            <apex:selectOptions value="{!monthItems}"/>
        </apex:selectList> 
            <!--commandButton:输入元素的按钮，按钮执行有控制器定义，收到响应后刷新页面-->                
            <apex:commandButton value="Apply" action="{!apply}" rerender="out" status="status"/>   
    </apex:form>
 
    <!--outputPanel:将组件组合在一起进行AJAX刷新-->
    <apex:outputPanel id="out">
        <!--显示AJAX更新请求状态的组件-->
        <apex:actionstatus id="status">          
            <apex:facet name="stop">
            </apex:facet>
        </apex:actionstatus>
    </apex:outputPanel>  
</apex:page>

public with sharing class SP_FilterConditionPageController {
    String displayMonth;
    String siteName;
    String currentDisplayMonth;
    //获取当前页面的对象ID
    Id accountId = ApexPages.CurrentPage().getparameters().get(‘id‘);
 
    public String getDisplayMonth() {
        if(displayMonth == null) {
            List<Account__c> accounts = [select Display_Months__c, Display_Site__c
                                         from Account__c
                                         where id = :accountId limit 1];
            displayMonth = accounts[0].Display_Months__c;
        }
        return displayMonth;
    }
 
    public void setDisplayMonth(String displayMonth) {
        this.displayMonth = displayMonth;     
    }
     
    public String getSiteName() {
        return siteName;
    }
 
    public void setSiteName(String siteName) {
        this.siteName = siteName;     
    }
     
    public PageReference apply() {
        if(displayMonth != null || siteName != null){         
            List<Account__c> accounts = [select Display_Months__c, Display_Site__c 
                                         from Account__c 
                                         where id = :accountId limit 1];
            for(Account__c account: accounts) {
                if(displayMonth != null) {
                    account.Display_Months__c = displayMonth;
                }
                if(siteName != null) {
                    account.Display_Site__c = siteName;
                }
            }
            if(Schema.sObjectType.Account__c.isUpdateable()) {
                //更新对象
                update accounts;
            }
        }
        
        //根据当前对象ID，产生新的页面
        PageReference pageRef = new pageReference(‘/‘ + accountId);
        pageRef.setRedirect(true);
        return pageRef;
    }
 
    public List<SelectOption> getSiteItems() {
       List<SelectOption> options = new List<SelectOption>();
       List<Sites__c> sites = [select WebEx_URL__c, Site_Status__c, Lockdown_Flag__c 
                               from Sites__c 
                               where Account__c = :accountId];
       for(Sites__c site: sites){
           if(site.Site_Status__c == ‘inactive‘ || site.Lockdown_Flag__c == ‘Not Available‘) {
               continue;
           }
           options.add(new SelectOption(site.Webex_URL__c, site.Webex_URL__c));
       }     
       return options;
    }
     
    public List<SelectOption> getMonthItems() {
       List<SelectOption> options = new List<SelectOption>();
       options.add(new SelectOption(‘Last 6 Months‘, ‘Last 6 Months‘));
       options.add(new SelectOption(‘Last 12 Months‘, ‘Last 12 Months‘));
       options.add(new SelectOption(‘Last 18 Months‘, ‘Last 18 Months‘));
       options.add(new SelectOption(‘Last 24 Months‘, ‘Last 24 Months‘));
       options.add(new SelectOption(‘Last 36 Months‘, ‘Last 36 Months‘));
        
       return options;
    }
}