Create a search or function to return the selected options as a value and text. For example.
0: [value : 123, text: abc]
1: [value :456, text: xyz]
then add the following code to display the selected options:
Field.insertSelectOption({
value: listOfTGFDAFs[j].getValue({
name: "value "
}),
text: listOfTGFDAFs[j].getValue({
name: "text"
}),
isSelected: (value == 456) ? true : false
});
To remove the select option
var FieldName= currentRecord.getField({
fieldId: 'fieldId'
});
FieldName.removeSelectOption({
value: null,
});