Hello again,

We are closing this bug, because the problem is not in the Grid, but in the SelectedItemsChanged handler logic. Here is what happens:

1. The Grid renders with no selected rows.
2. The user clicks on the Select All checkbox.
3. The Grid fires SelectedItemsChanged with all rows in the event argument.
4. The handler overrides and reduces the selected rows based on business logic.
5. Now the Grid knowns that only some rows are selected. The Select All checkbox is indeterminate.
6. (same as 2) The user clicks on the Select All checkbox.
7. (same as 3) The Grid fires SelectedItemsChanged with all rows in the event argument.

The above represents an endless loop, because the Grid's Select All checkbox' primary action is to select all rows if some of them are still not selected. When the Grid is inside another component, this leads to another render, which makes the problem visible, but does not cause the problem itself. The Grid SelectedItemsChanged handler must be reworked in order to achieve the desired behavior. Here is a possible option:

https://blazorrepl.telerik.com/wqOiuTui31uCMPdx53

Regards,
Dimo
Progress Telerik

Hi César,

Thank you for the runnable REPL test page.

That's a very peculiar problem indeed. It seems to be related to the combination of two things:

• The Grid is inside the ChildContent parameter of a component.
• The selected items are overridden on the fly.

It's not clear what exactly is causing the difference in behavior, so we will have to invest more time for research when we get to this.

In the meantime:

• I am converting your ticket to a public bug report for visibility and awarding you some Telerik points.
• I can suggest you to detect and workaround the issue in the SelectedItemsChanged handler like this: https://blazorrepl.telerik.com/cSELlElO578G12rF51

You may need to adjust the logic to match better your scenario. The idea is to detect when the "changed" selected items actually match the current ones.

    private void OnSelect(IEnumerable<Product> selectedProducts)
    {
        int newSelectedItemsCount = selectedProducts.Count();
        int allItemsCount = Math.Min(GridPageSize, GridData.Count());
        int discontinuedCount = GridData.Where(x => x.Discontinued).Count();

        if (newSelectedItemsCount == allItemsCount &&
            discontinuedCount > 0 &&
            SelectedReasons.Count() == allItemsCount - discontinuedCount)
        {
            SelectedItems = new List<Product>();
            SelectedReasons = new List<Product>();
        }
        else
        {
            SelectedItems = selectedProducts.Where(x => !x.Discontinued).ToList();
            SelectedReasons = selectedProducts.Where(x => !x.Discontinued);
        }
    }

Regards,
Dimo
Progress Telerik