Please update ng-easyui to newest version.
The ComboTreeGridComponent looks like this:
<eui-combotreegrid
placeholder="Select a row"
valueField="id"
textField="name"
[(ngModel)]="value"
[data]="data"
[panelStyle]="{width:'500px'}">
<eui-treegrid>
<eui-grid-column field="name" title="Name"></eui-grid-column>
<eui-grid-column field="size" title="Size"></eui-grid-column>
<eui-grid-column field="date" title="Date"></eui-grid-column>
</eui-treegrid>
</eui-combotreegrid>