load(
local!action:"",
local!gridSelectionCart: a!gridSelection(
    pagingInfo: a!pagingInfo(
      startIndex: 1,
      batchSize: 5,
      sort: a!sortInfo(field: "part",ascending: true)
    )
  ),
with(
  local!datasubsetCart: todatasubset(ri!itemsCart, local!gridSelectionCart.pagingInfo),
  a!formLayout(
    label:"Parts PO - Associate Vehicle",
    firstColumnContents: {
      a!gridField(
       label:"",
       totalCount:local!datasubsetCart.totalCount,
       columns: {
         a!gridTextColumn(label: "Mfr", field: "mfr", data: proper(index(local!datasubsetCart.data, "mfr", {}))),
         a!gridTextColumn(label: "Part", field: "part", data: proper(index(local!datasubsetCart.data, "part", {}))),
        a!gridTextColumn(label: "Vehicle No", field: "vehicle", data: index(local!datasubsetCart.data, "vehicle", {}))
        },
      identifiers: index(local!datasubsetCart.data, "id", {}),
      value: local!gridSelectionCart,
      saveInto:local!gridSelectionCart
   )
  },
    buttons: a!buttonLayout(
      primaryButtons: {
        a!buttonWidget(
          label: "Select Vehicle",
          style:"PRIMARY",
          value:"selectVehicle",
          saveInto:{
            local!action,
            a!save(ri!itemsCart.vehicle, "91524")
          }
        )
      },
      secondaryButtons:{}
    )
)
)
)

  
     
Sample Value for itemsCart:

{
   {id:"1", mfr:"ABC", part:"1234", vehicle:""},
   {id:"2", mfr:"DFE", part:"1111", vehicle:""}
}

CDT has below fields (Text type) : id, mfr, part, vehicle