asp.net Blazor:如何在点击按钮后立即显示正在加载的文本?

yhuiod9q  于 2023-06-07  发布在  .NET
关注(0)|答案(1)|浏览(271)

我有一个Blazor页面,用于创建一个用户,当按钮被单击时,我想显示一个加载文本。当它完成时,我想隐藏文本,这是我的代码:

<AuthorizeView>
    <Authorized>
        @if (@IsLoading) {
            <div>Loading</div>
        } else {
        <div class="add-user">
            <PageHeader Text="Add User" />

            <form Model="NewUser" class="user-form">
                <div class="line">
                    <label for="name">Name</label>
                    <input type="text" id="name" @bind="NewUser.Name" />
                </div>
                <div class="line">
                    <label for="email">Email</label>
                    <input type="email" id="email" @bind="NewUser.Email" />
                </div>
                <div class="line">
                    <div>
                        <label>Gender</label>
                    </div>
                    <div>
                        <label for="male">Male</label>
                        <input type="radio" id="male" name="gender" value="Male" @onchange="UpdateGender" checked="@IsMaleRadioButtonChecked" />
                        <label for="female">Female</label>
                        <input type="radio" id="female" name="gender" value="Female"
                            @onchange="UpdateGender" checked="@IsFemaleRadioButtonChecked"/>
                    </div>
                </div>
                <div class="line">
                    <label for="date-of-birth">Date of Birth</label>
                    <input type="date" id="date-of-birth" @bind="NewUser.DateOfBirth" />
                </div>
                <Button Text="Add User" OnClick="Save" />
            </form>
        </div>
        }
    </Authorized>
</AuthorizeView>

@code {
    private async void Save()
    {
        IsLoading = true;
        StateHasChanged();

        if (!AreFormValuesValid()) return;

        NewUser.Id = 0;
        NewUser.Password = NewUser.Name;
        NewUser.Role = roleService.Get("Participant");
        NewUser.Gender = Gender == "Male" ?
            Enumerations.Gender.Male : Enumerations.Gender.Female;

        if (await userService.AddOrUpdate(NewUser))
        {
            js.InvokeVoidAsync("alert", "User Added Successfully");

            NewUser = new User();
            Gender = "";
            StateHasChanged();
        } else
        {
            js.InvokeVoidAsync("alert", "Couldn't Save User");
        }
    
        IsLoading = false;
        StateHasChanged();
    }

加载文本出现在警告之后,但我希望加载文本在我单击按钮时出现。我如何改变我的代码来实现这一点。
我试了很多方法,都卡了好几个小时了,有谁能帮我吗?(这是一个Blazor服务器应用程序项目)

vdzxcuhz

vdzxcuhz1#

更新UI只能在await期间进行。如果消息只出现在警报之后,那么userService.AddOrUpdate()并不是真正的异步。添加延迟以更新屏幕:

//private async void Save()   -- avoid `async void`
    private async Task Save()
    {
        IsLoading = true;
      //StateHasChanged();      -- you get this one for free
        await Task.Delay(1);

        if (!AreFormValuesValid()) return;

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