Multi Drop down error in grid ?

Hello everyone,

Facing issue to display multi dropdown in editable grid. I want to display the interface having editable grid in record.

rows: a!forEach(
items: ri!purchaseDetails['recordType!{42faad32-9822-4aa3-903a-13045e657d3b}PMT Purchase Details.fields.{items}items'],
expression: a!gridRowLayout(
id: fv!index,
contents: {
a!textField(
label: "Description " & fv!index,
value: ri!purchaseDetails['recordType!{42faad32-9822-4aa3-903a-13045e657d3b}PMT Purchase Details.fields.{items}items'],
saveInto: fv!item.description
),
a!dropdownField(
label: "Category " & fv!index,
placeholder: "--- Select ---",
choiceLabels: { "Office Supplies", "Personal", "Other" },
choiceValues: { "Office Supplies", "Personal", "Other" },
value: ri!purchaseDetails['recordType!{42faad32-9822-4aa3-903a-13045e657d3b}PMT Purchase Details.fields.{items}items'],
saveInto: fv!item.category
),
a!integerField(
label: "Qty " & fv!index,
value: ri!purchaseDetails['recordType!{42faad32-9822-4aa3-903a-13045e657d3b}PMT Purchase Details.fields.{items}items'],
saveInto: fv!item.qty
),
a!integerField(
label: "Unit Price " & fv!index,
value: ri!purchaseDetails['recordType!{42faad32-9822-4aa3-903a-13045e657d3b}PMT Purchase Details.fields.{items}items'],
saveInto: fv!item.unitPrice
),
a!integerField(
label: "Amount " & fv!index,
value: ri!purchaseDetails['recordType!{42faad32-9822-4aa3-903a-13045e657d3b}PMT Purchase Details.fields.{items}items'],
saveInto: fv!item.amount
),
a!richTextDisplayField(
value: a!richTextIcon(
icon: "close",
altText: "delete " & fv!index,
caption: "Remove " & fv!item.description & " " & fv!item.category,
link: a!dynamicLink(
value: fv!index,
saveInto: {
a!save(
ri!purchaseDetails['recordType!{42faad32-9822-4aa3-903a-13045e657d3b}PMT Purchase Details.fields.{items}items'],
remove(
ri!purchaseDetails['recordType!{42faad32-9822-4aa3-903a-13045e657d3b}PMT Purchase Details.fields.{items}items'],
save!value
)
)
}
),

the above code throwing error in record