Angular 7 setting selected value not firing change event - angular7

Question

I have one single selection drop down and multi select drop down. Both is having dynamic value.
What I am doing is the I am clicking on edit button it shows modal inside modal there is select drop-downs of module and multi select of actions.
I am dynamically selecting module name it works perfectly but dependent multi-select is not working. I think single select is not firing change event.
HTML:
<div class="col-md-12">
<label for="module">Select Module</label>
<select class="form-control" (change)="onChangeModuleDD($event)" name="moduleSelection" required>
<option value="">-- Select Module --</option>
<option *ngFor="let module of allModuleData" [value]="module | json" [selected]="module.name == usermodule">{{
module.name
}}</option>
</select>
</div>
<div class="col-md-12">
<label for="actions">Select Actions/Charts</label>
<ng-multiselect-dropdown [placeholder]="'-- Select Action/Charts --'" [data]="dropdownList" [settings]="dropdownSettings"
(onSelect)="onItemSelect($event)" name="actionSelection" (onDeSelect)="OnItemDeSelect($event)"
(onSelectAll)="onSelectAll($event)" (onDeSelectAll)="onDeSelectAll($event)">
</ng-multiselect-dropdown>
</div>
COMPONENT:
onChangeModuleDD(event) {
this.selectedItems = [] // empty selected action array
this.dropdownList = []
let value = event.target.value
if (value) {
let parsedValue = JSON.parse(value)
this.usermodule = parsedValue.name
if (parsedValue.hasCRUD == 0) {
this.userListingApi.fetchAllDashboardAction().subscribe(res => {
this.dropdownList = []
for (let i = 0; i < res['data'].length; i++) {
this.dropdownList.push(res['data'][i])
}
})
} else {
this.userListingApi.fetchAllCRUDAction().subscribe(res => {
this.dropdownList = []
for (let i = 0; i < res['data'].length; i++) {
this.dropdownList.push(res['data'][i])
}
})
}
} else {
console.log('Nothing to display')
}
}
At the time of insertion it is working perfectly but when I select dynamically it is not working.
EDIT:
onItemSelect(item: any) {
this.selectedItems.push(item)
}
OnItemDeSelect(items: any) {
var id = items._id
this.selectedItems = this.selectedItems.filter((item) => item['_id'] !== id);
}
onDeSelectAll(items: any) {
this.selectedItems = items
}

Answer 1

in your component I cant see onItemSelect($event),OnItemDeSelect($event) and other multi select method bind to the event.
check this link :
https://www.npmjs.com/package/ng-multiselect-dropdown
add this in your component and try:
onItemSelect(item: any) {
console.log(item);
}

Answer 2

Not sure if it is even supposed to work. Please look at this issue: https://github.com/NileshPatel17/ng-multiselect-dropdown/issues/5.
Probably events get erased after reloading [data] (see my comment).