Automatically select the default value in mat-select if the array contains only one element, otherwise, populate the dropdown

I am facing a situation where I need to handle a select dropdown list (classification array). If the select list contains multiple values, it should be displayed as a dropdown. However, if there is only one element in the array, it should be automatically selected in the dropdown without the need for selection. I am looking to implement a condition wherein if the classification element length is less than or equal to 1, the element should be pre-selected in mat-select or the list should be displayed. Any advice on how to achieve this would be highly appreciated.

<form [formGroup]="myForm">      
      <div formGroupName="Details">        
          <mat-form-field appearance="outline">
            <mat-label class="required">Classification</mat-label>
            <mat-select
              formControlName="classification"              
            >
              <mat-option
                *ngFor="let type of classification"
                [value]="type.definedCode"
              >
                {{ type.definedMessage }}
              </mat-option>
            </mat-select>
          </mat-form-field>

TsFile

classification: any =[
         {
            "definedSetValueCode":"Dry",
            "definedSetValueIntMessage":"Seco"
         }
      ],

Answer №1

It is possible to set the selected value in the constructor. Assuming you are utilizing reactive forms based on your code example.

// Example of classification array
classification: any = [
  {
   "definedCode":"Dry",
   "definedValue":"Seco"
  }
],

constructor() {
 if (this.classification.length === 1) {
    this.myForm.controls.classification.setValue(this.classification[0].definedCode);
 }
}

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