In Blazor Telerik Grid, we can easily achieve using DetailTemplate. We donot have to keep grid inside another grid.

Here is the code snippet.
@page "/grid"
<h3>GridDemo</h3>
<TelerikGrid Data="salesTeamMembers"
OnRowCollapse="@OnRowCollapseHandler">
<DetailTemplate>
@{
var employee = context as MainModel;
<TelerikGrid Data="employee.Orders" Pageable="true" PageSize="5">
<GridColumns>
<GridColumn Field="OrderId"></GridColumn>
<GridColumn Field="DealSize"></GridColumn>
</GridColumns>
</TelerikGrid>
}
</DetailTemplate>
<GridColumns>
<GridColumn Field="Id"></GridColumn>
<GridColumn Field="Name"></GridColumn>
</GridColumns>
</TelerikGrid>
<br />
@code {
void OnRowCollapseHandler(GridRowCollapseEventArgs args)
{
MainModel item = args.Item as MainModel;
}
List<MainModel> salesTeamMembers { get; set; }
protected override void OnInitialized()
{
salesTeamMembers = GenerateData();
}
private List<MainModel> GenerateData()
{
List<MainModel> data = new List<MainModel>();
for (int i = 0; i < 5; i++)
{
MainModel mdl = new MainModel { Id = i, Name = $"Name {i}" };
mdl.Orders = Enumerable.Range(1, 15).Select(x => new DetailsModel { OrderId = x, DealSize = x ^ i }).ToList();
data.Add(mdl);
}
return data;
}
public class MainModel
{
public int Id { get; set; }
public string Name { get; set; }
public List<DetailsModel> Orders { get; set; }
}
public class DetailsModel
{
public int OrderId { get; set; }
public double DealSize { get; set; }
}
}