Hi Saurabh,

Greetings to you!

The apex:param tag is used to pass values from the Visualforce Page to the Apex Controller. Below is the sample code which I have tested in my org and it is working fine. Kindly modify the code as per your requirement.

sObject used: Student__c

Visualforce:

<apex:page controller="ApexParamDemoController">
  <apex:form id="form">
    <apex:pageBlock>
      <apex:pageBlockTable value="{!AllStu}" var="stu">
        <apex:column value="{!stu.Name}"/>
        <apex:column value="{!stu.Student_Name__c}"/>
        <apex:column>
          <apex:commandLink value="Delete" action="{!deleteStu}">
            <apex:param name="studentToDelete" value="{!stu.Id}" assignTo="{!stuDetailId}"/>
          </apex:commandLink>
        </apex:column>
      </apex:pageBlockTable>
    </apex:pageBlock>
  </apex:form>
</apex:page>

Controller:

public class ApexParamDemoController{

    //Property to hold the Id of the Record to be Deleted
    public Id stuDetailId {get; set;}
    
    //Query all the Students from the Database
    public List<Student__c> AllStu{
        get{ return [SELECT Id, Name, Student_Name__c FROM Student__c]; }
    }
    
    //Delete the Record from the Database
    public void deleteStu(){
        DELETE new Student__c(Id = stuDetailId);
    }
}

Or you can use below controller:

public class ApexParamDemoController{

    public List<Student__c> AllStu {get;set;}
    
    //Property to hold the Id of the Record to be Deleted
    public Id stuDetailId {get; set;}
    
    //Query all the Students from the Database
    public ApexParamDemoController{
        AllStu = [SELECT Id, Name, Student_Name__c FROM Student__c];
    }
    
    //Delete the Record from the Database
    public void deleteStu(){
        try {
            AllStu = [SELECT Id FROM Student__c WHERE Id = :stuDetailId];
            DELETE AllStu;
        } 
        catch (Exception e) {
            ApexPages.addMessages (e);
        }    
    }
}

The apex:param tag is responsible for passing the Id of the Student record. The apex:param passes the value contained in {!stu.Id} and assigns it to the property back in the Apex Class - RecordToDelete. So when the Delete button is clicked first the value will be assigned to the stuDetailId via the apex:param tag and then the method - deleteStu will be executed.

I hope it helps you.

Kindly let me know if it helps you and close your query by marking it as solved so that it can help others in the future. It will help to keep this community clean.

Thanks and Regards,
Khan Anas