为什么我不能在 Blazor 中使用输入值？

Question

我的 Blazor 应用有问题，有 2 个输入和 1 个按钮

<div class="form-group">
    <label class="form-label">Фильм</label>
    <input type="text" class="form-control" @bind="@filmname" placeholder="Введите название" required>
</div>

<div class="form-group">
    <label>Год</label>
    <input type="text" class="form-control" @bind="@year" placeholder="Введите год выхода фильма">
    <small class="form-text text-muted">Это необязательное поле</small>
</div>

<div class="col-4">
    <button class="btn btn-primary" id="sendbutton" type="submit" @onclick="GetData" disabled=@isLoading>Получить результат</button>
</div>

在 GetData 方法中，我使用 arg 调用另一个方法，例如“filmname + year”

@code {
    private List<string>? answers = null;
    private bool isLoading = false;
    public string filmname = "";
    public string year = "";
    private int check = 1;

    private async Task GetData()
    {
        check = 0;
        isLoading = true;
        string Text = "конец света";
       @* if (year != "")
            Text = filmname + " " + year;
        else
            Text = filmname;*@
    answers = new List<string>();
    check = 0;
    answers = await Data.Exec.GetScoreAsync(Text);
    isLoading = false;
    check = 1;
    StateHasChanged();
}
}

但是它没有出现在页面上，顺便说一句，如果它很重要，当我在 GetData 中定义字符串文本并且不触摸输入表单时一切正常。这里有什么问题？

尝试像这样显示“答案”的元素：

 @if (check == 0)
{
    <p>Loading [@answers?.Count] ...</p>
    <div class="spinner-border" role="status">
        <span class="sr-only">Loading...</span>
    </div>
}

@if (answers == null || answers.Count == 0)
{
    <p>no data</p>
}
else
{
    <p>@answers[0]</p>
    <p>@answers[1]</p>
    <p>@answers[2]</p>
    <p>@answers[3]</p>
}

获取数据

public static async Task<List<string>> GetScoreAsync(string FilmName)
    {
        List<string> alldata = new List<string>();
        List<string> comments = await Program.ParserExec(FilmName, false);
        List<string> scores = new List<string>();
        List<string> comments_new = Norm(comments);
        List<string> positive = new List<string>();
        List<string> negative = new List<string>();
        foreach (string comment in comments_new)
        {
            ModelInput input = new ModelInput()
            {
                Review = comment
            };
            ModelOutput result = ConsumeModel.Predict(input);
            scores.Add(result.Prediction);
            if (result.Prediction == "0")
                negative.Add(result.Prediction);
            else
                positive.Add(result.Prediction);
        }

        double last_score = 0;
        foreach (string score in scores)
            last_score += Convert.ToInt32(score);

        last_score /= scores.Count;
        last_score *= 10;
        alldata = new List<string>();
        alldata.Add(Math.Round(last_score, 1).ToString());
        alldata.Add(scores.Count.ToString());
        alldata.Add(positive.Count.ToString());
        alldata.Add(negative.Count.ToString());
        Dictionary<string, double> scoresDictionary = ExecIvi.Exec(FilmName);
        return alldata;

Answer 1

这是您目前向我们展示的演示工作版本：

@page "/"

<div class="form-group">
    <label class="form-label">Фильм</label>
    <input type="text" class="form-control" @bind="@filmname" placeholder="Введите название" required>
</div>

<div class="form-group">
    <label>Год</label>
    <input type="text" class="form-control" @bind="@year" placeholder="Введите год выхода фильма">
    <small class="form-text text-muted">Это необязательное поле</small>
</div>

<div class="col-4">
    <button class="btn btn-primary" id="sendbutton" type="submit" @onclick="GetData" disabled=@isLoading>Получить результат</button>
</div>


@if (check == 0)
{
    <p>Loading [@answers?.Count] ...</p>
    <div class="spinner-border" role="status">
        <span class="sr-only">Loading...</span>
    </div>
}

@if (answers == null || answers.Count == 0)
{
    <p>no data</p>
}
else
{
    <p>@answers[0]</p>
    <p>@answers[1]</p>
    <p>@answers[2]</p>
    <p>@answers[3]</p>
}

@code {
    private List<string>? answers = null;
    private bool isLoading = false;
    public string filmname = "";
    public string year = "";
    private int check = 1;

    private async Task GetData()
    {
        check = 0;
        isLoading = true;
        string Text = "конец света";
        @* if (year != "")
            Text = filmname + " " + year;
            else
            Text = filmname;*@
        answers = new List<string>();
        check = 0;
        answers = await GetAnswersAsync();
        isLoading = false;
        check = 1;
        // not needed;
        // StateHasChanged();
    }

    private async Task<List<string>> GetAnswersAsync()
    {
        await Task.Delay(1000);
        return new List<string> { "France", "Portugal", "Spain", "Australia" };
    }
}

如果您运行这段代码，它会做它应该做的事情。我用你的 GetScoreAsync 代替了一个简单的异步模拟器，但它做同样的事情。

所以：

在您调用 GetScoreAsync 之后放置一个断点并验证它 returns 您期望的列表。
将您的代码与我的代码进行比较，找出不同之处，或者您没有向我们展示的内容。有东西或者它会起作用！

注意：当问题几乎总是出在别处时，每个人都试图添加一个 StateHasChanged 来解决渲染问题。

Answer 2

愚蠢的错误，我所有的代码都在这样的标签中：

<form>
  all my code here
</form>

但是在@MrC aka Shaun Curtis 的回答中没有这个表单标签，我从我的代码中删除了它，现在一切正常，谢谢你的帮助

为什么我不能在 Blazor 中使用输入值？

Why i cannot use input values in Blazor?

c#

blazor