如何根据条件从mat-select中禁用Option

Question

I two mat-select, in the first one I select the type of Customer Individual or Organizational Customer. If User selects Ind Customer I show another mat-select. However, the issue is in second mat-select the dropdown options I want to disable certain input fields. How can I achieve that?

HTML Code to select Type of Customer

   <mat-form-field>
   <mat-label>Select Customer Type</mat-label>
   <mat-select (onSelectionChange)="getCustType($event)">
   <mat-option *ngFor="let obj of custType" (click)="getCustType(obj)" 
   [value]="obj" > {{ obj.viewValue }}</mat-option>
   </mat-select>
   </mat-form-field>

Typescript code:

custType: any[] = [{ value: 'indCust', viewValue: 'IndividualCustomer' }, { value: 'orgCust', viewValue: 'Organizational Customer' }];

Second Dropdown HTML CODE :

<mat-form-field class="col-sm-3">
    <mat-label>Select Option to Edit</mat-label>
    <mat-select (onSelectionChange)="getoptiontoedit($event)" >
      <mat-option *ngFor="let obj of optiontoeditlist" (click)="getoptiontoedit(obj)" [value]="obj"> {{ obj.viewValue }}</mat-option>
    </mat-select>
  </mat-form-field>

Typescript Code for Second Dropdown:

  optiontoeditlist: any[] = [
{ value: 'address', viewValue: 'Address' },
{ value: 'agentRelationship', viewValue: 'Agent Relationship' },
{ value: 'agreementRelationship', viewValue: 'Agreement Relationship' },
{ value: 'organizationCustomer', viewValue: 'Organization Customer' },
{ value: 'complaint', viewValue: 'Complaint' },
{ value: 'contact', viewValue: 'Contact' },
{ value: 'identification', viewValue: 'Identification' },
{ value: 'individualCustomer', viewValue: 'Individual Customer'}
];

I want to disable/hide individualCustomer option from the second dropdown if a user selects Organization Customer in the first dropdown similarly I want to disable/hide OrganazationalCustomer from the second dropdown if a user selects Individual Customer in the first dropdown.

Answer 1

You can implement a pipe for your second options list like below

@Pipe({ name: 'optfilter' })
export class OptionsFilterPipe implements PipeTransform {
   transform(alloptions: any[],firstSelectOpt: any<>) {
     return alloptions.filter(option => option.value.indexOf(firstSelectOpt.value)==-1); // or whatever your comparator condition is this just for indication
   }
 }

Then you can use it like

<mat-option *ngFor="let obj of optiontoeditlist | optFilter: 'selectedFirstOption'"