Tips for effectively updating multiple selection options from a component

I am currently in the process of making updates to a multi-select from the component.

Instead of using an array property as the model for the select, I opted for an object property. When an option is selected, the object property is updated accordingly.

Below is the code snippet for the select in the template:

<div class="form-group">
    <select multiple="" class="form-control" [(ngModel)]="recipe.mainIngredients" name="mainIngredients">
        <option *ngFor="let ingredient of mainIngredients" value="{{ ingredient._id }}">{{ ingredient.title }}</option>
     </select>
</div>

And here is the corresponding code in the component:

autoSelectMainIngredients(ingredient: Ingredient) {
    // Retrieve the ingredient id to be saved in the object property (which acts as the ngmodel)
    var mainIngredientId = this.mainIngredients.findObjectPropertyByAnotherProperty("title", ingredient.title, "_id");
    if (mainIngredientId){
        // Issue with select not updating
        this.recipe.mainIngredients.push(mainIngredientId);
    }
}

The multi-select does not get updated with the id when there are changes made to the model. Any suggestions on how I could achieve that successfully? Thank you.

UPDATE: If I manually update the ngmodel in ngOnInit:

this.recipe.mainIngredients.push("5a9e9e5a84d81edd7cb98e13");

Where "5a9e9e5a84d81edd7cb98e13" represents a valid value, everything works smoothly and the select displays the selection.

Answer №1

After some investigation, I discovered the solution was to trigger change detection by using the spread operator:

autoSelectMainIngredients(ingredient: Ingredient) {
    // Retrieves the ingredient id to be stored in the object property (ngmodel)
    var mainIngredientId = 
    this.mainIngredients.findObjectPropertyByAnotherProperty("title", ingredient.title, "_id");
    if (mainIngredientId){
        // Issue with selection not updating
        this.recipe.mainIngredients.push(mainIngredientId);
        this.recipe.mainIngredients = [...this.recipe.mainIngredients];
    }
}

Answer №2

Unfortunately, this approach does not seem to be effective when dealing with a p-multiselect component.

Here is the code snippet:

<p-multiSelect class="pull-down" id="checkedSecMail" dropdownIcon="pi pi-caret-down" [options]="req.secEmail"
              [(ngModel)]="req.selectedSecMail" >
              </p-multiSelect>

Within the TypeScript file:

 selectAllMailId($event,data){
      let rowData =  this.tempRecipients.filter(elem => elem.xyz == data.xyz);
      rowData[0].secEmail.map((secmails=> rowData[0].selectedSecMail.push(secmails.label)));
    }

This method is triggered upon clicking a checkbox. Although the multiselect checkboxes are being checked, unfortunately, the checked values are not being displayed.

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