You can try with this solution
I have create a demo on Stackblitz
Component.ts
editInfo(educationInfo) {
this.education_level = educationInfo.aa;
this.exam_title = educationInfo.bb;
this.gender = educationInfo.cc;
this.educationLevelChangeAction(this.education_level);
}
educationLevelChangeAction(education) {
this.exam_title = "";
let dropDownData = this.educationList.find((data: any) => data.educationLevelName === education);
if (dropDownData) {
this.degreeTitleList = dropDownData.degreeTitleList;
} else {
this.degreeTitleList = [];
}
}
Component.html
<mat-form-field>
<mat-select placeholder="Select Level of Education" name="education_level" (selectionChange)="educationLevelChangeAction(education_level)" [(ngModel)]="education_level" >
<mat-option *ngFor="let education of educationList" [value]="education.educationLevelName" >{{ education.educationLevelName }}</mat-option>
</mat-select>
</mat-form-field>
<mat-form-field>
<mat-select placeholder="Select Exam/Degree Title" name="exam_title" [(ngModel)]="exam_title">
<mat-option *ngFor="let degreeTitle of degreeTitleList" [value]="degreeTitle">{{ degreeTitle }}</mat-option>
</mat-select>
</mat-form-field>
<mat-form-field>
<mat-select [(ngModel)]="gender">
<mat-option *ngFor="let gender of genderList" [value]="gender">{{ gender }}</mat-option>
</mat-select>
</mat-form-field>
<p>You selected: {{education_level}} {{exam_title}} {{gender}}</p>