Resolving Predefined Dialog Rendering Beneath Modal Dialog in Blazor
Environment
| Product | Dialog for Blazor |
| Version | 7.1.0 and earlier |
Description
When using the Dialog component in Blazor, you may encounter an issue where a predefined confirmation dialog appears beneath an already open modal dialog. This can occur when handling logic in the VisibleChanged event of the main dialog, such as displaying a confirmation prompt before closing the modal. The root cause is related to the z-index of the dialog components.
This knowledge base article also answers the following questions:
- How can I ensure the predefined dialog appears above the modal dialog?
- What workaround addresses z-index issues with predefined dialogs?
- How to prevent predefined dialogs from rendering behind other components?
Solution
To resolve the issue, you have two options:
You can hide the close button of the main modal dialog via the ShowCloseButton Parameter, then handle the visibility of each dialog manually in a method.
Or, you can apply a workaround to adjust the z-index of the predefined dialog.
Set ShowCloseButton to false
Set the ShowCloseButton parameter of the main modal dialog to false, and move the confirmation logic to a button within the modal dialog. This ensures the predefined dialog does not overlap with the modal.
<TelerikDialog ShowCloseButton="false" @bind-Visible="@Visible">
<DialogContent>
Dialog Content
</DialogContent>
<DialogButtons>
<TelerikButton OnClick="@OnShowConfirm">ShowDialog</TelerikButton>
</DialogButtons>
</TelerikDialog>
@code {
[CascadingParameter]
private DialogFactory? Dialogs { get; set; }
private bool Visible { get; set; } = true;
private async Task OnShowConfirm()
{
bool isConfirmed = await Dialogs!.ConfirmAsync("Are you sure?");
if (isConfirmed)
{
Console.WriteLine("The user is sure, continue.");
Visible = false;
}
else
{
Console.WriteLine("The user changed their mind.");
}
}
}
Adjust the z-index Dynamically
Use JavaScript to dynamically adjust the z-index of the predefined dialog. This ensures it appears above the modal dialog. The approach targets the dialog wrapper using CSS selectors and modifies its z-index style.
This workaround relies on CSS selectors which may change in future updates of the Telerik theme. Use this approach with caution.
JavaScript
function bringDialogToTop() {
var dialogWrapper = document.querySelector(".k-window.k-dialog.k-alert").closest(".k-dialog-wrapper");
if (dialogWrapper) {
dialogWrapper.style.zIndex = parseInt(dialogWrapper.style.zIndex) + 2;
}
}Razor
@inject IJSRuntime js
<TelerikDialog Visible="@Visible" VisibleChanged="OnDialogClosingAsync">
</TelerikDialog>
@code{
[CascadingParameter]
private DialogFactory Dialogs { get; set; }
private bool Visible { get; set; } = true;
private bool ShouldFocusDialog { get; set; }
private async Task OnDialogClosingAsync(bool currentVisibility)
{
ShouldFocusDialog = true;
await ShowConfirm(currentVisibility);
}
private async Task ShowConfirm(bool currentVisibility)
{
bool isConfirmed = await Dialogs.ConfirmAsync("Are you sure?");
if (isConfirmed)
{
Console.WriteLine("The user is sure, continue.");
Visible = currentVisibility;
}
else
{
Console.WriteLine("The user changed their mind");
}
}
protected override async Task OnAfterRenderAsync(bool firstRender)
{
if (ShouldFocusDialog)
{
ShouldFocusDialog = false;
await Task.Delay(1);
await js.InvokeVoidAsync("bringDialogToTop");
}
await base.OnAfterRenderAsync(firstRender);
}
}