Data hierarchy

Hey hey, back with another question as the first one was answered perfectly!

I'm trying to build a DataGrid Master Detail Hierarchy on demand.
I can expand the rows, but they are always empty.

    List<itemList> itemList;
int pageSize = 15;
RadzenGrid<itemList> grid;

protected override async Task OnInitializedAsync()
    string sql = "SELECT val1, val2,val3 FROM table";
    itemList = await _data.LoadData<itemList, dynamic>(sql, new { }, _config.GetConnectionString("default"));
void Change(object value) // Update num of rows
async void RowExpand(itemList item)
    if (item.val4 == null)
        string sql = "SELECT val1, val2, val3 FROM table2 WHERE val1 = @ForeignKey";
        item.val4 = await _data.LoadData<secondItemList, dynamic>(sql, new { ForeignKey = item.val1}, _config.GetConnectionString("default"));

Without anything on how the grid is bound and configurated we will unable to help you. Check also the forum FAQ for reference.

Here we go:

    <RadzenDropDown @bind-Value="pageSize" Data="@(new List<int>() { 10, 15, 50, 100 })" Style="margin-bottom: 20px" Change="@Change" />
<RadzenGrid @ref="grid" AllowFiltering="true" FilterCaseSensitivity="FilterCaseSensitivity.CaseInsensitive" FilterMode="FilterMode.Advanced" AllowPaging="true" PageSize=@pageSize
            AllowSorting="true" Data="@itemList" TItem="itemList" AllowColumnResize="true" ColumnWidth="150px">
    <Template Context="item">
        <RadzenGrid AllowFiltering="true" AllowPaging="true" AllowSorting="true" Data="@item.val4" TItem="secondItemList">
                <RadzenGridColumn TItem="secondItemList" Property="val1" Title="Value One" />
                <RadzenGridColumn TItem="secondItemList" Property="val2" Title="Value Two" />
                <RadzenGridColumn TItem="secondItemList" Property="val3" Title="Value Three" />
        <RadzenGridColumn TItem="itemList" Property="value1" Title="PSO Sort">
                Total equips: <b>@itemList.Count()</b>
        <RadzenGridColumn TItem="itemList" Property="val2" Title="Value Two" />
        <RadzenGridColumn TItem="itemList" Property="val3" Title="Value Three" />

It's not clear where RowExpand is attached that will populate your child data.

1 Like

Yes, that was indeed an issue! Now the data is loading, but with a side effect:
When I expand the data doesnt show. If I expand the next one, the data from the first one shows. If I expand the third one, the data from the second one shows...

I'm afraid that I cannot help in this case and you will need to debug your app to check what's going on. Check also the code created by Radzen Hiearchy/Master detail pages template with our OData Sample service for example:

I managed to fix it by adding:

await grid.Reload();

In RowExpand
Thanks for your help!

1 Like

Better fix: Change return type void to Task:

async void RowExpand(itemList item)


async Task RowExpand(itemList item)