当前线程未与调度程序关联.使用 InvokeAsync() 在触发渲染时将执行切换到调度程序

Question

我正在研究 Dotnet Core Blazer，并在删除事件后使用 EventCallBack 绑定父网格时出现以下错误。下面是使用子组件的代码

<tbody>
@foreach (var employee in Employees)
{
<BlazorAppDemo.Pages.Controls.EmployeeList Employee="employee"
ShowFooter="ShowFooter"
OnEmployeeSelectionChange="onEmployeeSelectionChanged"
btnDeleteClick="OnEmployeeDeleted" >
</BlazorAppDemo.Pages.Controls.EmployeeList>
}
</tbody> 

员工列表子组件如下

<tr>
@*<td>@Employee.EmployeeId</td>*@
<td><input type="checkbox" @onchange="CheckBoxChanged" /></td>
<td>@Employee.Department.DepartmentName</td>
<td>@Employee.FirstName</td>  
<td>@Employee.DateOfBirth.ToShortDateString()</td>
<td><img class="card-img-top img-thumb" style="width:50px;height:50px" src="@Employee.PhotoPath" /></td>
@if (ShowFooter)
{
<AuthorizeView Roles="Admin" Policy="OldEmployeeBefore2020">
<Authorized>
<td>
<a href="@($"employeedetails/{Employee.EmployeeId}")" class="btn btn-primary m-1">View</a>
<a href="@($"employeeEdit/{Employee.EmployeeId}")" class="btn btn-primary m-1">Edit</a>
@*<a href="#" class="btn btn-danger m-1">Delete</a>*@
<button class="btn btn-danger m-1" @onclick="btnDelete_Click">
</button>
</td>
</Authorized>
</AuthorizeView> 
}

删除按钮事件 ：

[Parameter]
public EventCallback<int> btnDeleteClick { get; set; }
protected async Task btnDelete_Click()
{
var response = await EmployeeService.Delete(Employee.EmployeeId).ConfigureAwait(false);
if (string.IsNullOrEmpty(response.ErrorMessage))
{               
await btnDeleteClick.InvokeAsync(Employee.EmployeeId);               
//NavigationManager.NavigateTo("employee");
}
}

父页面已订阅删除事件：

protected async Task OnEmployeeDeleted(int id)
{
var response = await EmployeeService.GetEmployees().ConfigureAwait(false);
if (response.Result != null)
{  
Employees = response.Result.Result; 
}
else
{
PageMessage = response.ErrorMessage;
}
}

Answer 1

您应该删除.ConfigureAwait(false)(据我所知，这是 2 倍(。

在 Blazor 中正确使用 async/await 时，几乎不需要它。

当您使用它时，您要求在不同的线程上运行事件的其余部分。在大多数情况下是错误的线程。