Programmatically adding a column to a NSTableView

Question

I created a NSTableView in IB with 3 columns (first name, last name and email). I want to add a 4th one (age).

    let column = NSTableColumn(identifier: NSUserInterfaceItemIdentifier(rawValue: "age"))
    column.title = "Age"
    column.width = CGFloat(120)
    column.minWidth = CGFloat(4)
    self.tableView.addTableColumn(column)

The column is added but its content is empty.

I wonder if there is not an issue with the cell view but I don't know how to add it. Can somebody help?

Thank you.

The whole code is added below. Code in in Swift 4 Xcode 9

import Cocoa

class Person: NSObject {
var firstName : String
var lastName : String
var emailId : String
var age : Int

init(firstName: String, lastName: String, emailId: String, age: Int){
    self.firstName = firstName
    self.lastName = lastName
    self.emailId = emailId
    self.age = age
}
}

class ViewController: NSViewController {

@IBOutlet weak var tableView: NSTableView!

var tableViewData: [Person] = [Person(firstName: "John", lastName: "Apple", emailId: "d.v@stack.com", age: 35),Person(firstName: "Phil", lastName: "Grant", emailId: "dg@yo.com", age: 50),Person(firstName: "lou", lastName: "groth", emailId: "AV@flock.com", age: 14)]

override func viewDidLoad() {
    super.viewDidLoad()

    let column = NSTableColumn(identifier: NSUserInterfaceItemIdentifier(rawValue: "age"))
    column.title = "Age"
    column.width = CGFloat(120)
    column.minWidth = CGFloat(4)
    self.tableView.addTableColumn(column)

    self.tableView.delegate = self
    self.tableView.dataSource = self
    self.tableView.reloadData()
}
}

extension ViewController:NSTableViewDataSource, NSTableViewDelegate{

func numberOfRows(in tableView: NSTableView) -> Int {
    return tableViewData.count
}

func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView?{
    guard let vw = tableView.makeView(withIdentifier: tableColumn!.identifier, owner: self) as? NSTableCellView else { return nil }

    switch tableColumn?.identifier.rawValue  {
    case "firstName"?:
        vw.textField?.stringValue = tableViewData[row].firstName
    case "lastName"?:
        vw.textField?.stringValue = tableViewData[row].lastName
    case "emailId"?:
        vw.textField?.stringValue = tableViewData[row].emailId
    case "age"?:
        vw.textField?.integerValue = tableViewData[row].age
    default:
        return nil
    }
    return vw
}
}

Answer 1

Use the identifier property.

let tableColumn = NSTableColumn()
tableColumn.headerCell.title = "Age"
tableColumn.headerCell.alignment = .center
tableColumn.identifier = "age"
self.tableView.addTableColumn(tableColumn)

Answer 2

I know this is old, but someone might find this helpful. Docs for makeView says:

If a view with the specified identifier can't be instantiated from the nib file or found in the reuse queue, this method returns nil.

If you add a column programmatically it won't be in the nib, so makeView will return nil and your column will be empty. To make it show, you could use NSTextField instead of NSTableCellView like this:

func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView?
{
    var vw = tableView.makeView(withIdentifier: tableColumn!.identifier, owner: self) as? NSTextField

    if vw == nil
    {
        vw = NSTextField(labelWithString: "")
        vw?.identifier = tableColumn!.identifier // allows this new cell to be reused
    }

    switch tableColumn?.identifier.rawValue  {
    case "firstName":
        vw?.stringValue = tableViewData[row].firstName
    case "lastName":
        vw?.stringValue = tableViewData[row].lastName
    case "emailId":
        vw?.stringValue = tableViewData[row].emailId
    case "age":
        vw?.stringValue = String(tableViewData[row].age)
    default:
        return nil
    }

    return vw
}