关于c＃：简单If / Else Razor语法

Simple If/Else Razor Syntax

我正在尝试使用以下代码在foreach中执行简单的If / Else：

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@{
var count = 0;
foreach (var item in Model)
{
if (count++ % 2 == 0)
{
@:<tr class="alt-row">
} else {
@:<tr>
}
<td>
@Html.DisplayFor(modelItem => item.Title)
</td>
<td>
@Html.Truncate(item.Details, 75)
</td>
<td>
<img src="@Url.Content("~/Content/Images/Projects/")@item.Images.Where(i => i.IsMain == true).Select(i => i.Name).Single()"
alt="@item.Images.Where(i => i.IsMain == true).Select(i => i.AltText).Single()" class="thumb" />
</td>
<td>
@Html.ActionLink("Edit","Edit", new { id=item.ProjectId }) |
@Html.ActionLink("Details","Details", new { id = item.ProjectId }) |
@Html.ActionLink("Delete","Delete", new { id=item.ProjectId })
</td>
</tr>
}
}

我收到一个解析错误"遇到不匹配的开始标签的结束标签" tr"。您的开始/结束标签是否正确平衡？"。似乎if语句不起作用。

只需将其用作结束标记：

@:</tr>

并保持原样。

Seems like the if statement doesn't wanna' work.

它工作正常。您在这里使用2种语言空间工作，似乎最好不要在边界上分开打开/关闭三明治。

相关讨论

也许有些话题，但是对于现代浏览器(IE9和更高版本)，您可以使用css奇/偶选择器来实现所需的功能。

1 2	tr:nth-child(even) { /* your alt-row stuff /} tr:nth-child(odd) { / the other rows */ }

要么

1 2	tr { /* all table rows / } tr:nth-child(even) { / your alt-row stuff */}

为了摆脱if / else的尴尬，您可以使用using块：

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@{
var count = 0;
foreach (var item in Model)
{
using(Html.TableRow(new { @class = (count++ % 2 == 0) ?"alt-row" :"" }))
{
<td>
@Html.DisplayFor(modelItem => item.Title)
</td>
<td>
@Html.Truncate(item.Details, 75)
</td>
<td>
<img src="@Url.Content("~/Content/Images/Projects/")@item.Images.Where(i => i.IsMain == true).Select(i => i.Name).Single()"
alt="@item.Images.Where(i => i.IsMain == true).Select(i => i.AltText).Single()" class="thumb" />
</td>
<td>
@Html.ActionLink("Edit","Edit", new { id=item.ProjectId }) |
@Html.ActionLink("Details","Details", new { id = item.ProjectId }) |
@Html.ActionLink("Delete","Delete", new { id=item.ProjectId })
</td>
}
}
}

可重用的元素，使添加属性更加容易：

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//Block is take from http://www.codeducky.org/razor-trick-using-block/
public class TableRow : Block
{
private object _htmlAttributes;
private TagBuilder _tr;

public TableRow(HtmlHelper htmlHelper, object htmlAttributes) : base(htmlHelper)
{
_htmlAttributes = htmlAttributes;
}

public override void BeginBlock()
{
_tr = new TagBuilder("tr");
_tr.MergeAttributes(HtmlHelper.AnonymousObjectToHtmlAttributes(_htmlAttributes));
this.HtmlHelper.ViewContext.Writer.Write(_tr.ToString(TagRenderMode.StartTag));
}

protected override void EndBlock()
{
this.HtmlHelper.ViewContext.Writer.Write(_tr.ToString(TagRenderMode.EndTag));
}
}

使剃刀语法更清晰的Helper方法：

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public static TableRow TableRow(this HtmlHelper self, object htmlAttributes)
{
var tableRow = new TableRow(self, htmlAttributes);
tableRow.BeginBlock();
return tableRow;
}