c# - Blazor(客户端)StateHasChanged() 不更新页面

Question

我的页面(组件)上有一个按钮，单击时会调用 Refresh() 方法。此方法然后调用 StateHasChanged()，但不会重新加载页面。 GetData() 正在调用外部 API 以从数据库加载数据。

<button class="btn btn-warning" @onclick="Refresh">Refresh</button>

code {

protected override async Task OnInitializedAsync()
    {
        try
        {
            await GetData();
            base.OnInitialized();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

    }

protected async Task GetData()
    {
        try
        {
            results = await HttpClient.GetJsonAsync<Results[]>(ServiceEndpoints.GET_RESULTS);
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error retrieving data from Oracle.", ex.Message);
        }
    }

public void Refresh()
        {
            StateHasChanged();          
        }

我的页面(组件)还有一个表单，该表单具有可以更改的预加载输入。我希望用户能够编辑表单，但能够通过单击按钮来刷新页面以取回原始数据。这是在以前版本的 Blazor 上工作的，是否有关于此的已知问题？

@page "/"
@inherits IndexBase

<EditForm Model="@results">
<label><strong>Select a job to view its current parameters</strong></label>
<div class="currentJobForm">

    <InputSelect id="jobSelect" @bind-Value="jobSelected">
        @foreach (var items in results)
        {
            <option value="@items.JOB_NAME">@items.JOB_NAME</option>
        }
    </InputSelect>
    <button class="btn btn-warning" @onclick="SaveChanges" disabled="@IsDisabled">Save</button>
    <button class="btn btn-warning" @onclick="Refresh">Refresh</button>
    <button class="btn btn-danger" @onclick="DeleteJob">Delete Job</button>
</div>    
    <label><strong>Notify Parameters</strong></label>
    <div class="notifyParametersForm">
        @foreach (var item in results.Where(i => i.JOB_NAME == jobSelected))
        {
            <div class="issueDescription">
                <label><strong>Issue Description</strong></label>
                <InputText id="issueDesc" @bind-Value="item.JOB_HEADER" placeholder="Enter New Issue Description" />
            </div>
            <div class="sendSlack">
                <label><strong>Send Slack</strong></label>
                <InputSelect id="sendSlackSelect" @bind-Value="item.SENDSLACK">
                    @foreach (var items in InitializeData.SendSlacks)
                    {
                        <option value="@items.SendSlackName">@items.SendSlackName</option>
                    }                        
                </InputSelect>
            </div>
            <div class="slackUser">
                <label><strong>Slack User</strong></label>
                <InputText id="slackUser" @bind-Value="item.SLACK_USER" placeholder="Enter New Slack User" />
            </div>
            <div class="slackChannel">
                <label><strong>Slack Channel</strong></label>
                <InputSelect id="sendSlackChannel" @bind-Value="item.SLACK_CHANNEL">
                    @foreach (var items in InitializeData.SlackChannels)
                    {
                        <option value="@items.SlackChannelName">@items.SlackChannelName</option>
                    }                        
                </InputSelect>
            </div>
            <div class="slackUrl">
                <label><strong>Slack URL</strong></label>
                <InputText id="slackUrlTextBox" @bind-Value="item.SLACK_URL" placeholder="Enter New Slack Url" />
            </div>
            <div class="sendMail">
                <label><strong>Send Mail</strong></label>
                <InputSelect id="sendMailSelect" @bind-Value="item.SENDMAIL">
                    @foreach (var items in InitializeData.SendMails)
                    {
                        <option value="@items.SendMailName">@items.SendMailName</option>
                    }
                </InputSelect>
            </div>
            <div class="mailFrom">
                <label><strong>From:</strong></label>
                <InputText id="from" @bind-Value="item.MAILFROM" placeholder="Enter New Mail From" />
            </div>
            <div class="mailTo">
                <label><strong>To:</strong></label>
                <InputText id="to" @bind-Value="item.MAILTO" placeholder="Enter New Mail To" />
            </div>
            <div class="subject">
                <label id="subjectLabel"><strong>Subject:</strong></label>
                <InputText id="subject" @bind-Value="item.EMAIL_SUBJECT" placeholder="Enter New Subject" />
            </div>
        }
    </div>
</div>

Answer 1

正如所有其他答案所解释的那样，有多种方法可以正确重置您的表单，但除了 BrinkDaDrink 答案之外，没有一种方法会告诉您如何通过按一下按钮来刷新页面。

在我看来，BrinkDaDrink 答案增加了不必要的复杂性。

我的解决方案是创建一个名为 refresh 的空组件页面，如下所示:

@page "/refresh"
@inject NavigationManager NavigationManager

@code {

    protected override void OnInitialized()
    {
        NavigationManager.NavigateTo("");
    }

}

此页面将立即重定向到您的原始页面，立即刷新页面和所有数据。

您可以在原始页面中创建刷新方法，如下所示:

public void RefreshPage()
{
    NavigationManager.NavigateTo("refresh");
}

这比迄今为止提供的任何其他解决方案更快地解决您提到的问题:

I want the user to be able to edit the form, but be able to refresh the page by clicking the button to get back the original data

您还可以使用它通过将以下内容添加到刷新页面来将参数传递到刷新页面:

@page "/refresh"
@page "/refresh/{text}"
@inject NavigationManager NavigationManager

@code {
    [Parameter]
    public string Text { get; set; }

    protected override void OnInitialized()
    {
        NavigationManager.NavigateTo(Text);
    }

}