Kendo DropDownList 在加载时先于 DataTextField 显示 DataValueField [英] Kendo DropDownList Shows DataValueField Prior to DataTextField when Loading

问题描述

以下代码加载 Kendo DropDownList，但在页面呈现时，它首先显示 DataValueField，然后是 DataTextField.一秒钟后它绑定到 DataTextField 就好了，但我不想在它呈现时显示数值.有没有人知道在渲染的第一秒只显示 DataTextField 值而不显示 DataValueField 的方法?

The following code loads a Kendo DropDownList, but while the page renders it first shows the DataValueField prior to the DataTextField. It binds just fine to the DataTextField after a second, but I would not like to show the numeric value while it renders. Does anyone know of a way to make only the DataTextField value be shown and not the DataValueField for that first second while it renders?

@(Html.Kendo().DropDownList()
              .Name("SomeName")
              .DataTextField("SomeTextField")
              .DataValueField("SomeValueField")
              .DataSource(source => {
                  source.Read(read => {
                      read.Url(Url.ExtensionMethodThatReturnsURL("SomeAction", "SomeController"));
                  }).ServerFiltering(true);
              })
              .HtmlAttributes(new { @Class = "some-class" })
              .Value(businessKey.ToString())
              .Events(e => e.Change("Some.Javascript.onEventHandler"))
              .Deferred()
    )

推荐答案

该问题可能是由 .Deferred() 语句引起的，该语句延迟了小部件初始化，直到延迟的脚本通过

The problem is probably caused by the .Deferred() statement, which delays the widget initialization until the deferred scripts are rendered via

@Html.Kendo().DeferredScripts()

我认为在呈现 DropDownList 文本框和小部件初始化之间会发生一些耗时的事情.所以你在普通的非初始化文本框中看到了数值.我有两个建议:

I assume there is something time consuming taking place between the rendering of the DropDownList textbox and the widget initialization. So you are seeing the numeric value inside the plain non-initialized textbox. I have two suggestions:

• 如果可能，将 DeferredScripts() 调用移近 DropDownList 声明.
• 如果上述方法不可行或没有产生预期的结果，则暂时隐藏 DropDownList 直到它被初始化.

• move the DeferredScripts() call closer to the DropDownList declaration, if possible.
• if the above is not possible or does not yield the desired result, then hide the DropDownList temporarily until it is initialized.

例如:

DropDownList 和 JavaScript

@(Html.Kendo().DropDownList()
    .Name("products")
    .DataTextField("ProductName")
    .DataValueField("ProductID")
    .Filter("contains")
    .DataSource(source =>
    {
        source.Read(read =>
        {
            read.Action("GetProducts", "Home");
        })
        .ServerFiltering(true);
    })
    .Value("3")
    .Deferred()
    .HtmlAttributes(new { @class = "temporary-hidden" })
)

// ...Something else here...

@Html.Kendo().DeferredScripts()

<script>

    // place this script immediately after the DeferredScripts() call
    // and in a document.ready handler to ensure it is executed at the right time

    $(function () {
        $(".temporary-hidden").removeClass("temporary-hidden");
    })

</script>

CSS

.temporary-hidden
{
    visibility: hidden;
}

与 display:none 相反，visibility:hidden 样式会使 DropDownList 文本框即使在隐藏时也会占用屏幕空间，因此您将避免闪烁和布局重新调整.

Contrary to display:none, the visibility:hidden style will make the DropDownList textbox occupy space on the screen even while hidden, so you will avoid flickering and layout readjustments.

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