html - 如何使用 Material Angular 将嵌套的json数组显示到html表中

Question

我正在尝试将嵌套的 json 数组显示到我的 Material Angular 表中。如果我的 json 没有嵌套数组，我的数据就可以正常工作。

杰森

{
"rows": [
    {
        "mst": {
            "field": "createDate",
            "value": "2017-06-02"
        },
        "gsc": {
            "field": "Account/Audit/Creation/Date",
            "value": "2017-06-02"
        }
    },
    {
        "mst": {
            "field": "startDate"
        },
        "gsc": {
            "field": "startDate"
        }
    },
    {
        "mst": {
            "field": "status",
            "value": "ACTIVE"
        },
        "gscs": [
            {
                "field": "Account/LineOfBusiness/Type~Status",
                "value": "C~A"
            },
            {
                "field": "Account/LineOfBusiness/Type~Status",
                "value": "I~A"
            }                
        ],
        "gscvalue": "Active"
    },
    {
        "mst": {
            "field": "statusDate"
        },
        "gsc": {
            "field": "statusDate"
        }
    },
    {
        "mst": {
            "field": "statusReason"
        },
        "gsc": {
            "field": "statusReason"
        }
    },
    {
        "mst": {
            "field": "deliveryMethod",
            "value": "PAPER"
        },
        "gscs": [
            {
                "field": "Electronic",
                "value": "N"
            },
            {
                "field": "ElectronicOutsourced",
                "value": "N"
            },
            {
                "field": "Hardcopy",
                "value": "Y"
            }
        ],
        "gscvalue": "Paper"
    },
    {
        "mst": {
            "field": "statementFormat",
            "value": "Standard"
        },
        "gsc": {
            "field": "?"
        }
    },
    {
        "mst": {
            "field": "statementLanguagePreference",
            "value": "Spanish"
        },
        "gsc": {
            "field": "Account/Language",
            "value": "S"
        },
        "gscvalue": "Spanish"
    },
    {
        "mst": {
            "field": "type",
            "value": "RES"
        },
        "gsc": {
            "field": "Account/Type",
            "value": "RES"
        }
    }
]
}

HTML

<div class="example-container mat-elevation-z8" *ngIf="rows?.length>0">
<table mat-table [dataSource]="dataSource">

<ng-container matColumnDef="mst Fields">
  <th mat-header-cell *matHeaderCellDef> mst Fields </th>
  <td mat-cell *matCellDef="let row" class="tablePadding"> {{row.mst.field}} </td>
</ng-container>

<ng-container matColumnDef="mst">
  <th mat-header-cell *matHeaderCellDef> mst value </th>
  <td mat-cell *matCellDef="let row"> {{row.mst.value}} </td>
</ng-container>

<ng-container matColumnDef="gsc Fields">
  <th mat-header-cell *matHeaderCellDef> gsc Fields </th>
  <td mat-cell *matCellDef="let row"> {{row.gsc.field}} </td>
</ng-container>

<ng-container matColumnDef="gsc">
  <th mat-header-cell *matHeaderCellDef> gsc value </th>
  <td mat-cell *matCellDef="let row"> {{row.gsc.value}} </td>           
</ng-container>

<tr mat-header-row *matHeaderRowDef="displayedColumns; sticky: true"></tr>
<tr mat-row *matRowDef="let row; columns: displayedColumns; let row"></tr>

modal.ts

export class ResultField {
field: string;
value: string;
valueList: string[];
}

export class ResultRow {
mst: ResultField;
gsc: ResultField;
gscs: ResultField[];
gscValue: String;
}

我当前的表将一直显示数据，直到它到达 mst.field{status}。我收到一个错误

SystemComponent.html:29 ERROR TypeError: Cannot read property 'field' of undefined

我明白这个错误是因为我的 html 中当前的逻辑。我该如何解决这个问题？

因此，我不想将 gscs.field 放在单独的列中，我希望将这些值放入 gsc.field 列和 gsc.value 列中的 gscValue 中。

尝试

<ng-container matColumnDef="gsc Fields">
  <th mat-header-cell *matHeaderCellDef> gsc Fields </th>
  <td mat-cell *matCellDef="let row" *ngIf="row.gsc.field"> {{row.gsc.field}} </td>
<td mat-cell *matCellDef="let row" *ngIf="row.gsc.field"> {{row.gscs.field}} </td>
</ng-container>

但是对于 Angular 逻辑，一个标签中只能有一个 * 指令。

我最接近的引用是 Need to display Nested JSON Object in Material Data Table
但没有可靠的答案。

尝试 2

我尝试使用更简单的方法来打印我的数据。

<div>
  <h1>Testing</h1>

  <div *ngFor="let row of rows">
    <!-- <p *ngIf="row.gsc.field">{{row.gsc.field}}</p>
    <p *ngIf="row.gsc.value">{{row.gsc.value}}</p> -->
    <p>{{row.mst.field}}</p>
    <p>{{row.mst.value}}</p>   


  <div *ngFor= "let gscs of row.gscs">
    <p *ngIf="gscs.field">{{gscs.field}}</p>
    <p *ngIf="gscs.value">{{gscs.value}}</p>
</div>
<p *ngIf = "row.gscvalue">{{row.gscvalue}}</p>
  </div>  
</div>

使用此代码片段，我可以提取嵌套值，但是当我取消注释这两行时，我收到与上述相同的错误。

<!-- <p *ngIf="row.gsc.field">{{row.gsc.field}}</p>
<p *ngIf="row.gsc.value">{{row.gsc.value}}</p> -->

错误类型错误:无法读取未定义的属性“字段”

使用上面提供的 JSON，我想创建一个如下图所示的表。

Answer 1

似乎您只需要嵌套您的 ngIf :

<ng-container matColumnDef="gsc Fields">
  <th mat-header-cell *matHeaderCellDef> gsc Fields </th>
  <td mat-cell *matCellDef="let row">
    <ng-container *ngIf="row.gsc?.field; else fieldArray">
      {{row.gsc.field}} 
    </ng-container>
    <ng-template #fieldArray>
      <div class="sub-cell" *ngFor="let field of row.gscs"> <!-- need the appropriate css -->
        {{field.field}} {{field.value}}
      </div>
    </ng-template>
  </td>
</ng-container>

在您的值(value)列中，您想要更像:

<ng-container matColumnDef="gsc">
  <th mat-header-cell *matHeaderCellDef> gsc value </th>
  <td mat-cell *matCellDef="let row"> {{row.gsc?.value || row.gscvalue}} </td>           
</ng-container>

不确定这是 100% 但应该接近