Angular 如何定义对象数组，对象数组|角度2

我不断得到一个未定义类型错误“error-TypeError:cannotreadproperty'length'of undefined”。在我的类中，我有一个array对象，它有另一个array对象。基本上我有一个类似这样的类：

export class ICase {
  shareCaseReason?: string;
  caseDetails?: ICasedeit;
  involvedPersonsAndOrganisations?: IInvolved;
  policeOfficers?: IPolice[];
  incidents?: IIncident[];
  offences?: IOffence[];
  suspect?: ISuspectDetails[];
  witnessStatements?: IStatements[];
  interviewNotes?: IIncident[];
  notebookEntries?: INotebook;
  victims?: IVictim[];
  witnesses?: IWitness[];
  physicalEvidence?: IEvidence[];
  otherDocumentaryEvidence?: IDocEvidence[];
}

export class ISuspectDetails {
  ageRange: string;
  juvenile: IJuvenile;
  timeincustody: ITimeInCustody;
  particularNeeds: IParticularNeeds;
  complaints: IComplaint[];
  principalEvidenceTypes: IEvidenceTypes;
  motivationTypes: IMotivationTypes;
  bailRecords: IBailRecords; 

  constructor() {
    this.complaints = [];
  };
}

<div class="container-fluid scrollable-grid"  *ngIf='template && template.shareCase && template.shareCase.case && template.shareCase.case.suspects'>
  <div class="row gridData" *ngFor="let suspect of template.shareCase.case.suspects">
    <div class="col-2"> {{suspect?.chargeDate}} </div>
    <div class="col-1"> {{suspect?.complaint?.length}} </div>
  </div>
</div>

我想显示ISuspectDetails对象数组中的属性。该类如下所示：

export class ICase {
  shareCaseReason?: string;
  caseDetails?: ICasedeit;
  involvedPersonsAndOrganisations?: IInvolved;
  policeOfficers?: IPolice[];
  incidents?: IIncident[];
  offences?: IOffence[];
  suspect?: ISuspectDetails[];
  witnessStatements?: IStatements[];
  interviewNotes?: IIncident[];
  notebookEntries?: INotebook;
  victims?: IVictim[];
  witnesses?: IWitness[];
  physicalEvidence?: IEvidence[];
  otherDocumentaryEvidence?: IDocEvidence[];
}

export class ISuspectDetails {
  ageRange: string;
  juvenile: IJuvenile;
  timeincustody: ITimeInCustody;
  particularNeeds: IParticularNeeds;
  complaints: IComplaint[];
  principalEvidenceTypes: IEvidenceTypes;
  motivationTypes: IMotivationTypes;
  bailRecords: IBailRecords; 

  constructor() {
    this.complaints = [];
  };
}

<div class="container-fluid scrollable-grid"  *ngIf='template && template.shareCase && template.shareCase.case && template.shareCase.case.suspects'>
  <div class="row gridData" *ngFor="let suspect of template.shareCase.case.suspects">
    <div class="col-2"> {{suspect?.chargeDate}} </div>
    <div class="col-1"> {{suspect?.complaint?.length}} </div>
  </div>
</div>

我想在我的组件中显示ngFor上ISuspectDetails投诉数组的长度。我的模板如下所示：

export class ICase {
  shareCaseReason?: string;
  caseDetails?: ICasedeit;
  involvedPersonsAndOrganisations?: IInvolved;
  policeOfficers?: IPolice[];
  incidents?: IIncident[];
  offences?: IOffence[];
  suspect?: ISuspectDetails[];
  witnessStatements?: IStatements[];
  interviewNotes?: IIncident[];
  notebookEntries?: INotebook;
  victims?: IVictim[];
  witnesses?: IWitness[];
  physicalEvidence?: IEvidence[];
  otherDocumentaryEvidence?: IDocEvidence[];
}

export class ISuspectDetails {
  ageRange: string;
  juvenile: IJuvenile;
  timeincustody: ITimeInCustody;
  particularNeeds: IParticularNeeds;
  complaints: IComplaint[];
  principalEvidenceTypes: IEvidenceTypes;
  motivationTypes: IMotivationTypes;
  bailRecords: IBailRecords; 

  constructor() {
    this.complaints = [];
  };
}

<div class="container-fluid scrollable-grid"  *ngIf='template && template.shareCase && template.shareCase.case && template.shareCase.case.suspects'>
  <div class="row gridData" *ngFor="let suspect of template.shareCase.case.suspects">
    <div class="col-2"> {{suspect?.chargeDate}} </div>
    <div class="col-1"> {{suspect?.complaint?.length}} </div>
  </div>
</div>

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非常感谢您的帮助！刚从Angular开始，我掌握了很多东西，但我似乎在任何地方都找不到解决这个问题的方法

您的html中有输入错误，

投诉

而不是

投诉

。改为：

{{可疑？投诉？长度}

---

您的html中有一个输入错误，

投诉

，而不是

投诉

。改为：

{{可疑？投诉？长度}

---

非常感谢你！我现在觉得很傻，因为我看不见它！非常感谢你！我现在觉得很傻，因为我看不见它！