如何实时显示/隐藏元素（Blazor）？

Question

我有一个图像，我想在用户填写所有文本字段后显示。

我试过使用disabled属性，但这似乎不起作用。还有其他见解吗？

这是我当前的代码：

<EditForm EditContext="@EditContext" style="max-width:800px;" onkeydown="javascript: DisableEnterKey();">
            <FluentValidator />

            <img src="images/approval-16-grey.ico" alt="Image" disabled="@OkayDisabled">


            <p class="statp">How many families and/or individuals are living on your land?</p><br />

            <label class="statlabel" for="amountOfFamilies">Amount of families:</label><br />
            <InputNumber id="fams" for="indivNum" class="input" @bind-Value="@familyData.IndividualAmount" onwheel="this.blur()" placeholder="Families..." autofocus />
            <ValidationMessage For="() => familyData.IndividualAmount" />

            <br /><hr class="statHR" />

            <label class="statlabel" for="amountOfIndividuals">Amount of single individuals: </label><br />
            <InputNumber id="individuals" for="famNum" class="input" @bind-Value="@familyData.FamilyAmount" onwheel="this.blur()" placeholder="Individuals..."/>
            <ValidationMessage For="() => familyData.FamilyAmount" />

            <br /><hr class="statHR" />

            <label class="statlabel" for="names"> Please enter all of the names here:</label><br />
            <InputTextArea id="names" class="textArea" rows="4" cols="18" @bind-Value="@PersonName" placeholder="Names of all individuals..." />
            <ValidationMessage For="() => familyData.PersonName" />


        </EditForm>

        </div>
    </ul>


    @code 
    {
        private EditContext? EditContext;
        public FamilyData Model = new FamilyData();

        protected string OkayDisabled { get; set; } = "disabled";

        protected override void OnInitialized()
        {
            EditContext = new EditContext(Model);
            EditContext.OnFieldChanged += EditContext_OnFieldChanged;

            base.OnInitialized();
        }

        protected override void OnAfterRender(bool firstRender)
        {
            base.OnAfterRender(firstRender);

            SetOkDisabledStatus();
        }

        private void EditContext_OnFieldChanged(object? sender, FieldChangedEventArgs e)
        {
            SetOkDisabledStatus();
        }

        private void SetOkDisabledStatus()
        {
            if(EditContext.Validate())
            {
                OkayDisabled = null;
            }
            else
            {
                OkayDisabled = "disabled";
            }
        }
    }

Answer 1

更改OkayDisabled为 a bool，然后在您的图像周围执行此操作

@if (!OkayDisabled)
{
  <img src=".....whatever" etc />
}

您可能还想@bind:event="oninput"在使用@bind.

Answer 2

我不会将标志绑定到禁用属性（图像的禁用属性只是将其变灰），而是将其绑定到具有以下属性的 css 类：display: none;

.hidden {
    display: none;
}

<img class="@(ShouldShowImage? "hidden" : string.Empty)">

Answer 3

该hiddenHTML属性也适用于隐藏的元素。

<p hidden>This paragraph should be hidden.</p>

绑定到模型：

 <p hidden="@HideLabel">I am Hidden When HideLabel == true</p>

 <p hidden="@(!HideLabel)">I am Hidden when Hidelabel == false</p>

 
 <button @onclick="@Toggle">Show/Hide</button>

 @code {
      private bool HideLabel   {get;set;} = false;
      private void Toggle()
      {
         HideLabel =   !HideLabel;
      }      
 }