c# - 如何检查 cshtml 中的空值/空值

Question

<b>Start Date: </b>@employee["StartDate"].<br />

使用 MVC Razor 3/C#，如何检查employee["StartDate"]cshtml 中的值是否为空/空？因此，如果是，我改为显示：

<b>Start Date: </b>Unknown.<br />

我试过了：

@if(employee["StartDate"] == null){<b>Start Date: </b>Unknown.<br />}

但这不起作用。

score 14 · Accepted Answer

Try

<b>Start Date: </b>@(employee["StartDate"] ?? "Unknown").<br />

?? return the left-side value, or the right-side value if the left-side value is null.

score 5 · Accepted Answer

If you are only worried about null or empty

@(String.IsNullOrEmpty(employee["StartDate"])?"Unknow":employee["StartDate"])

score 3 · Accepted Answer

我最终使用了这个：

@if(employee["StartDate"].ToString() == ""){<b>Start Date: </b>Unknown.<br />}
else{<Start Date: </b>@employee["StartDate"].<br />}

但是有没有一种“更干净”的方式来写这个？

score 1 · Accepted Answer

If startDate is a DateTime try to compare it with DateTime.MinValue.

If you have more problems you can put breakpoint in razor code to see what exactly is that field

score -1 · Accepted Answer

像下面这样尝试过，我已经厌倦了类似的空检查，它应该可以工作

@if(employee["StartDate"] != DateTime.MinValue){
  <Start Date: </b>@employee["StartDate"].<br />
}
else{
  <b>Start Date: </b>Unknown.<br />
}

5 回答 5