Reference a VisualForce component attribute to use in itself

apexvisualforcevisualforce-component

I would like to know how to get an attribute of a component in a visualForce code.

In this code, wrappers is a map and I would like to put the value of the pageBlocktable to a List which is contained in my map, it is accessible by the key "cable".
Unfortunately, when I try to hardcode the value I want in the get function with a string, I have an error.

I have tried to replace what is is the circle pointed by the arrow with :

Cable
"Cable"
'Cable'
\"Cable\"
\'Cable\'

But none of them seem function, so I tried to get it by putting in a title and acces it later.

I also dont think it is possible to use the apex:param to set the variable of my controller and reference it.

Can someone help me getting the right synthax or tell me how to achieve what I am trying to do?

thanks

Best Answer

You can't reference a component's attributes that way in Visualforce. You can only reference public Apex variables and methods, and Visualforce variables (e.g. from apex:pageBlockTable or apex:variable). As an aside, you only use ! at the beginning of a merge field, and you don't use .get on a Map, but just the ordinary map[key] notation. {wrappers[test.title]} would have been the appropriate way to reference the value, if it were allowed.

Related Solutions

[SalesForce] Reference inner class in Visualforce component

I've run across this as well and also resorted to refactoring my inner-class to the top level. The documentation isn't clear on this, but considering that the type attribute is considered limited, I think it's fair to assume that only top-level classes are supported. From the Visualforce Developer's Guide (pg. 285):

Only the following data types are allowed as values for the type attribute:

Primitives, such as String, Integer, or Boolean.
sObjects, such as Account, My_Custom_Object__c, or the generic sObject type.
One-dimensional lists, specified using array-notation, such as String[], or Contact[].
Maps, specified using type="map". You don't need to specify the map's specific data type.
Custom Apex types (classes).

[SalesForce] Visualforce component use custom id attribute

Controlling the Id can be achieved but no precisely as you mentioning .But there is a way to get Id populated as you want in Visualforce Page.

One way to do the same will be assigning Ids to All Compoenents on Page

Official Document link

<apex:page id="thePage">

<apex:form id="theForm">
    <apex:pageBlock id="thePageBlock" title="Targeting IDs with $Component">
        <apex:pageBlockSection id="theSection">
            <apex:pageBlockSectionItem id="theSectionItem">
                All the alerts refer to this component.

                <p>The full DOM ID resembles something like this:<br/>
                thePage:theForm:thePageBlock:theSection:theSectionItem</p>
            </apex:pageBlockSectionItem>

            <!-- Works because this outputPanel has a parent in common 
                 with "theSectionItem" component -->
            <apex:outputPanel layout="block" styleClass="clicker"
                onclick="alert('{!$Component.theSectionItem}');">
                First click here
            </apex:outputPanel>
        </apex:pageBlockSection>

        <apex:pageBlockButtons id="theButtons" location="bottom">
            <!-- Works because this outputPanel has a grandparent ("theSection")
                 in common with "theSectionItem" -->
            <apex:outputPanel layout="block" styleClass="clicker"
                onclick="alert('{!$Component.theSection.theSectionItem}');">
                Second click here
            </apex:outputPanel>

            <!-- Works because this outputPanel has a distant ancestor ("theForm")
                 in common with "theSectionItem" -->
            <apex:outputPanel layout="block" styleClass="clicker"
                onclick="alert('
                {!$Component.theForm.thePageBlock.theSection.theSectionItem}');">
                Third click here
            </apex:outputPanel>
        </apex:pageBlockButtons>

    </apex:pageBlock>

    <!-- Works because this outputPanel is a sibling to "thePageBlock",
         and specifies the complete ID path from that sibling -->
    <apex:outputPanel layout="block" styleClass="clicker"
        onclick="alert('{!$Component.thePageBlock.theSection.theSectionItem}');">
        Fourth click here
    </apex:outputPanel>

    <hr/>

    <!-- Won't work because this outputPanel doesn't provide a path 
         that includes a sibling or common ancestor -->
    <apex:outputPanel layout="block" styleClass="clicker"
        onclick="alert('{!$Component.theSection.theSectionItem}');">
        This won't work
    </apex:outputPanel>

    <!-- Won't work because this outputPanel doesn't provide a path 
         that includes a sibling or common ancestor -->
    <apex:outputPanel layout="block" styleClass="clicker"
        onclick="alert('{!$Component.theSectionItem}');">
        Won't work either
    </apex:outputPanel>

</apex:form>

Basically once you provide the ID for the Page and other sections the DOM will follow specific pattern which can be easily predicted and wont change across instances .

Best Answer

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[SalesForce] Visualforce component use custom id attribute

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