Posted 15 June 2026, 9:27 am EST - Updated 15 June 2026, 9:28 am EST
Hi,
We recently upgraded our Blazor Server application from C1.Blazor.Input 8.0.20241.872 to 10.0.20252.1316 and noticed that C1AutoComplete stopped working — users cannot select any value from the dropdown.
Environment:
Target Framework: .NET 10
Blazor Hosting Model: Blazor Server
Broken versions:
C1.Blazor.Core: 10.0.20252.1316 (also tested 10.0.20261.33)
C1.Blazor.Input: 10.0.20252.1316 (also tested 10.0.20261.33)
C1.Blazor.Grid: 10.0.20252.1316
C1.Blazor.DataPager: 10.0.20252.1316
C1.Blazor.DateTimeEditors: 10.0.20252.1316
Working version:
All C1 packages: 8.0.20241.872 with .NET 8 target framework
What we observed:
When a user clicks an item in the C1AutoComplete dropdown, the dropdown closes but the selected value is not retained. The SelectedValueChanged callback never fires. We confirmed this with Visual Studio breakpoints — the handler is never hit on version 10.
Actual application code:
<C1AutoComplete [at]ref="cbActivityType"
ItemsSource="[at]ActivityTypeList"
ValueMemberPath="Code"
DisplayMemberPath="Name"
T="ActivityType"
SelectedValue="[at]selectedActivityCode"
SelectedValueChanged="onActivityChanged">
<ItemTemplate Context="item">
<div class="autocomplete-item" title="[at]item.ActivityTypeDesc">
[at]item.Name
</div>
</ItemTemplate>
</C1AutoComplete>
private string selectedActivityCode = "";
private C1AutoComplete<ActivityType> cbActivityType;
private void onActivityChanged(object selectedValue)
{
if (!string.IsNullOrEmpty(selectedValue?.ToString()))
selectedActivityCode = selectedValue.ToString();
StateHasChanged();
}
Result on version 10:
Dropdown opens and shows items
User clicks an item, dropdown closes
onActivityChanged breakpoint never hits
selectedActivityCode never updates
Binding approaches we tried on version 10 — all failed:
Approach 1 - Original:
SelectedValue="[at]selectedActivityCode"
SelectedValueChanged="onActivityChanged"
Approach 2:
[at]bind-SelectedValue="[at]selectedActivityCode"
Approach 3:
SelectedItem="[at]selectedItem"
SelectedItemChanged="onItemChanged"
Approach 4:
SelectedValueChanged="[at](EventCallback.Factory.Create(this, onActivityChanged))"
None of the above approaches fire the event on version 10. All work correctly on version 8.
To rule out our application code we created an isolated test:
<C1AutoComplete ItemsSource="[at]items"
T="string"
SelectedValueChanged="[at]onValueChanged" />
<p>Selected: [at]testValue</p>
[at]code {
string testValue = "";
List<string> items = new()
{
"Option 1",
"Option 2",
"Option 3"
};
private void onValueChanged(object val)
{
testValue = val?.ToString() ?? "";
StateHasChanged();
}
}
Result:
C1.Blazor.Input 8.0.20241.872 + .NET 8 → selecting “Option 1” correctly shows “Selected: Option 1”
C1.Blazor.Input 8.0.20241.872 + .NET 10 → selection works locally but when deployed to IIS server threw the following error:
Microsoft.JSInterop.JSException: Could not find 'C1DropDown.init'
('C1DropDown' was undefined).
at C1.Blazor.Core.C1View.OnAfterRenderAsync(Boolean firstRender)
This appeared to be a browser cache issue and resolved after clearing cache.
C1.Blazor.Input 10.0.20252.1316 + .NET 10 → selecting anything shows nothing, event never fires
C1.Blazor.Input 10.0.20261.33 + .NET 10 → same issue, event never fires
To resolve this we also had to downgrade the target framework to .NET 8. With .NET 8 + C1 version 8 the application works correctly.
This means to fix the issue we currently have to downgrade both the C1 packages AND the target framework — which is not ideal as we want to stay on .NET 10.
Suspected cause:
Looking at the 2025 v2 release notes, we noticed this change under Input:
“Enhanced C1DropDown to restore focus to the previously focused element when the component closes, preventing focus-jumping issues and ensuring correct focus behavior in grid editors and other child content.”
We noticed this change in the 2025 v2 release notes under Input — could this be related to the issue we are facing?
Question:
We are not sure if this is a bug or if there is a new recommended way to use C1AutoComplete in version 10. Could you please help us understand what changed and how we should handle value selection going forward?
We are currently staying on C1 version 8 with .NET 8 as a workaround but would like to upgrade to version 10 with .NET 10 when this is resolved.
Thank you.
