[SalesForce] reRender problem with apex inputFile can not be used in conjunction with an action component

Rerendering is not supported when you have an apex:inputFile component. There's no workaround, as the platform simply will not allow it. The best you can do is to move the apex:inputFile into an apex:iframe which will leave the rest of the "page" alone.

BTW If you are looking to rerender the entire page, that sounds the same as a refresh.

You can use an actionRegion to define a scope for a commandButton or commandLink. This is sufficient to allow inputFile to happily co-exist with reRender attributes. Note that the actionRegion must contain all the information necessary to update the page, because only the components inside the actionRegion is processed by the server. Here's a simple example:

Controller

public with sharing class renderFile {
    public transient Blob fileBody { get; set; }
    public String contentType { get; set; }
    public String fileName { get; set; }
    public string[] items { get; set; }

    public renderFile() {
        items = new string[0];
    }

    public void save() {
        Document d = new Document(FolderId=UserInfo.getUserId(), Name=fileName, Body=fileBody, ContentType=contentType);
        insert d;
        items.add('Uploaded '+d.Name+' as ID '+d.Id);
    }
    public void reRender() {
        items.add('Item: '+(items.size()+1));
    }
}

Page

<apex:page controller="renderFile">
    <apex:form id="form">
        <apex:pageBlock >
            <apex:pageBlockButtons location="bottom">
                <apex:actionRegion id="area51" renderRegionOnly="false">
                    <apex:commandButton value="Something" reRender="form" action="{!reRender}"/>
                </apex:actionRegion>
                <apex:commandButton value="Save" action="{!save}"/>
            </apex:pageBlockButtons>
            <apex:pageBlockSection >
                <apex:repeat value="{!items}" var="value">
                    <apex:outputText >{!value}</apex:outputText>
                </apex:repeat>
                <apex:inputFile contentType="{!contentType}" fileName="{!fileName}" value="{!fileBody}" />
            </apex:pageBlockSection>
        </apex:pageBlock>
    </apex:form>
</apex:page>