英文:
SignalR causing null reference exception while adding custom dialog services
问题
我们正在尝试使用SignalR添加自定义服务，但在调用自定义服务时会抛出空异常。如果我们在mainLayout.razor中指定组件标记为<BlazorApp3.DialogForms.Test/>，则项目无法运行。
示例链接: https://uploadnow.io/f/Y59l8d9
附带示例中是否缺少任何配置？
需要在没有任何异常的情况下运行具有自定义对话服务的SignalR示例。
英文:
We are trying to add custom services with SignalR, but it throws a null exception when we invoke the custom services. If we specify the component tag in mainLayout.razor like <BlazorApp3.DialogForms.Test/>, it is unable to run the project.
Sample: https://uploadnow.io/f/Y59l8d9
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Are we missing any configuration in the attached sample?
Need to run the signalR with custom dialog service sample without any exception
答案1
得分: 1
将您的 DialogService 类更改如下，问题可能会得到解决。
using System;
using Microsoft.AspNetCore.Components;
namespace BlazorApp3.DialogForms
{
public class DialogService
{
private event Action<DialogOptions> dialogInstance;
public event Action<DialogOptions> DialogInstance
{
add => dialogInstance += value;
remove => dialogInstance -= value;
}
public async Task Open(DialogOptions options)
{
// 调用 Test 以更新并显示具有选项的对话框
this.dialogInstance?.Invoke(options);
}
}
}
英文:
Change your DialogService class like below and the issue could be fixed.
using System;
using Microsoft.AspNetCore.Components;
namespace BlazorApp3.DialogForms
{
public class DialogService
{
private event Action<DialogOptions> dialogInstance;
public event Action<DialogOptions> DialogInstance
{
add => dialogInstance += value;
remove => dialogInstance -= value;
}
public async Task Open(DialogOptions options)
{
// Invoke Test to update and show the dialog with options
this.dialogInstance?.Invoke(options);
}
}
}
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