How can I get this button to pass data to controller?

Question

UPDATE

I have the following function:

<apex:actionFunction action="{!selectRec}" name="recordSelectFunction">
                        <apex:param name="selectedID" assignto="{!selectedRec}" value=""/>
                    </apex:actionFunction>
        </apex:form>

And this, inside of an iterative block (where the iterated var record is "item".

<a style="cursor:pointer; font-size:14px" onclick="recordSelectFunction('{!item.Id}')">Select Record</a>

Based on documentation, expecting onclick to call that apex:actionFunction, which passes "item.id" as the parameter, meaning my controller var would be set to that ID. !selectRec in the controller simply prints out the variable to start, and it's null.

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I would like a button to be clicked and use param to set a certain variable in the controller to a value from the VF page. I am hoping someone can either tell me why it's not possible, or (hopefully) how to correctly develop this. See bottom for link to the StackExchange question that got me started.

I have a block table that loops over a list of records from the controller, and I output things like a date field, ID, Name, etc. and the last thing I do it add the following button:

<apex:form>
 <apex:commandButton value="Select Record" action="{!selectRecord}">
                         <apex:param name="recordID" assignto="{!selectedRec}" value="{!item.ID}"/>

                         // "item" is the iterated var

  </apex:commandButton>
  </apex:form>

the goal is for that button to call a function

public pageReference selectRecord(){
    system.debug('the record ID is : ' + selectedRec);
    return null;
}

Answer 1

Take a look at the apex:actionFunction. This allows you to generate a JavaScript function and to call this function from JavaScript in your page (e.g. in an onclick event). The parameters to the function can be bound (or "assigned") to properties on the controller, and these will be updated before the associated method is called on the controller.

Please do note that you will need to indirectly invoke the action function if you need the invocation within an iteration (which you appear to need).

Answer 2

You are getting value as null in the controller because you are not using rerender attribute of apex:commandButton. If you miss this attribute then form will get submitted but value will not get assigned.

In the below code, rerendering the form element. You could choose proper element name for rerendering.

<apex:form>
    <apex:commandButton value="Select Record" action="{!selectRecord}" rerender="myForm">
        <apex:param name="recordID" assignto="{!selectedRec}" value="{!item.ID}"/>
        // "item" is the iterated var
    </apex:commandButton>
</apex:form>

Controller

public String selectedRec {get;set;}

public pageReference selectRecord(){
    system.debug('the record ID is : ' + selectedRec);
    return null;
}

For more information, refer apex:actionFunction

Answer 3

You may want to refer to my answer( ActionFunction not working properly.Values not getting passed to controller ) on a similar post. Its just a Salesforce issue which is not documented anywhere since I last checked. It's something which creates so many issues when trying to pass data to apex without using rerender in apex:actionfunction