Looking through the examples I can't find one with SelectionMode="GridSelectionMode.Multiple" and using a RowTemplate.
ADMIN EDIT: This is not a bug in the component, an example of how this can be implemented by the app is available in the comments.
I'm not sure what I should be binding my checkbox to so it accurately reflects selection state.
From the RowTemplate Example adding SelectionMode:
<TelerikGrid Data=@GridData
@bind-SelectedItems="@SelectedItems"
SelectionMode="GridSelectionMode.Multiple" Height="@Height">
<RowTemplate Context="product"> @*Trying to inspect what is generated in the examples I came up with this, but not sure what to bind to checked*@
<td role="gridcell" colspan=0 data-col-index="0">
<span>
<input class="k-checkbox k-grid-checkbox telerik-blazor" type="checkbox" />
</span>
</td><td> <img class="rounded-circle" src="@($"images/{product.ProductId}.jpg")" alt="Alternate Text" /> @product.ProductName </td> <td> @(String.Format("{0:C2}", product.UnitPrice)) </td> </RowTemplate> <GridColumns> <GridColumn Field=@nameof(Product.ProductName) Title="Product Name" /> <GridColumn Field=@nameof(Product.UnitPrice) Title="Unit Price" /> </GridColumns> </TelerikGrid>