I did this way, But always detail info drop down is enabled depending on the source_info value isselected in the last row

Also in the save method always the source info value is the value of the last selected row. How can we get the source_info value for each row in the controller save method?

<apex:page controller="controller_test" action="{!init1}">
<apex:form>
<apex:pageblock>

<apex:pageBlock title="Reporting" >

<apex:pageBlockTable value="{!Event_Results}" var="eve" id="TheTable">

<apex:column headervalue="Source">
<apex:selectList value="{!source_info}" multiselect="false" size="1" onselect="RRTheTable">
<apex:selectOptions value="{!Source_Items}"/>
<apex:actionSupport event="onchange" rerender="list2,look_up"/>
</apex:selectList>
</apex:column>

<apex:column headervalue="Detail Info">
<apex:selectList value="{!Detail_Name}" multiselect="false" size="1" disabled="{!source_info!='Web'}" id="list2" >
<apex:selectOptions value="{!Detail_Items}" />
</apex:selectList>
<apex:inputField value="{!eve.AccountId}" rendered="{!source_info=='Email'}" id="look_up"/>
</apex:column>

</apex:pageBlockTable>

<apex:pageBlockButtons location="Bottom">
<apex:commandButton action="{!save}" value="Save"/>
</apex:pageBlockButtons>

</apex:pageBlock>
</apex:form>
</apex:page>

My original requirement was to display dropdown in the Detail info column when Source_info='Web' and display lookUp to Account when  source_info='Email'. For this i am trying below but for some reason rendered and rerender is not working. Not sure if this is because it is in pageblocktable. 

Also Event Accountid in inputfield is not displaying lookup, rather the id value is being displayed.

Can you please help??

I have been trying very hard on this but no luck :smileysad:

This is my page

<apex:page controller="controller_test" action="{!init1}">
<apex:pageBlock title="Reporting" >

<apex:pageBlockTable value="{!Event_Results}" var="eve" id="TheTable" >

<apex:Column headervalue="Source" >
<apex:selectList value="{!source_info}" title="Items" size="1" id="List1" >
<apex:selectOptions value="{!Source_Items}" />
<apex:actionSupport event="onchange" reRender="test1, list2A, list2B" status="gettingDetailnames" />
</apex:selectList>
</apex:Column>

<apex:Column headervalue="Detail Info" >
<apex:outputtext rendered="{!source_info=='Web'}" id="test1">here</apex:outputtext>
<apex:selectList value="{!Detail_Name}" title="Detail" size="1" rendered="{!source_info=='Web'}" id="list2A" >
<apex:selectOptions value="{!Detail_Items}"/>
</apex:selectList>
<apex:inputField value="{!eve.AccountId}" rendered="{!source_info!='Web'}" id="list2B"/>
</apex:Column>

<apex:actionStatus id="gettingDetailnames" startText="Retrieving Detail Info..."/>

</apex:pageBlockTable>
<apex:pageBlockButtons location="Bottom">
<apex:commandButton action="{!save}" value="Save" />
</apex:pageBlockButtons>
</apex:pageBlock>
</apex:form>
</apex:page>

 This is the class

public with sharing class controller_test
{
List<Event> events_info = new List<Event>();
List<String> WhoIds = new List<String>();
List<Contact> Contacts_info = new List<Contact>();
public String source_info,detail_Name;
public String getSource_info()
{
return source_info;
}
public void setSource_info(String source_info)
{
this.source_info= source_info;
}
public String getDetail_Name()
{
return detail_Name;
}

public void setDetail_Name(String detail_Name)
{
this.detail_Name= detail_Name;
}
public List<SelectOption> getSource_Items()
{
List<SelectOption> options3 = new List<SelectOption>();
options3.add(new SelectOption('--Select--','--Select--'));
options3.add(new SelectOption('Web','Web'));
options3.add(new SelectOption('Email','Email'));
options3.add(new SelectOption('Phone','Phone'));
return options3;
}
public List<SelectOption> getDetail_Items()
{

List<SelectOption> options3 = new List<SelectOption>();
options3.add(new SelectOption('--Select--','--Select--'));
options3.add(new SelectOption('Google','Google'));
options3.add(new SelectOption('Yahoo','Yahoo'));
options3.add(new SelectOption('rediff','rediff'));
return options3;
}
public PageReference init1()
{
events_info=[Select Id,AccountId,What.Name,Who.Name,Who.Email,Who.Id from Event Where OwnerId = :UserInfo.getUserId() and order by Whoid limit 3];
for(Integer i=0;i<events_info.size();i++)
{
WhoIds.add(events_info[i].Who.Id);
}
for(Contact c:[Select Id,Email,Accountid from Contact where Id IN:WhoIds order by Id])
{
Contacts_info.add(c);
}
return null;
}
Public List<Event> getEvent_Results()
{
return events_info;
}
Public List<Contact> getContact_Results()
{
return Contacts_info;
}
public PageReference save()
{
for(Integeri=0;i<events_info.size();i++)
{
System.debug('source_info value is '+source_info);

System.debug('Detail_info value is '+detail_Name);
}
return null;
}
public PageReference Refresh()
{
PageReference pr1=new PageReference('/006/o');
system.debug('source_info value is '+source_info);
pr1.setRedirect(true);
return pr1;
}
}