Difference between Razor single statement and block

Question

Why does the first segment work and the second throw an "Invalid expression term '<' error at the label tag?

First segment:

@foreach( var f in new List<List<string>>{ new List<string>{ new List<string>{ "PumpSize", "Pump Size" },
new List<string>{ "PumpType", "Pump Type" }, 
new List<string>{ "WellHead", "Well Head" } } )
{
    <label>@f[1]
    </label>
}

Second segment:

@{
    var fields = new List<List<string>>{ new List<string>{ new List<string>{ "PumpSize", "Pump Size" },
        new List<string>{ "PumpType", "Pump Type" }, 
        new List<string>{ "WellHead", "Well Head" } };
    fields.ForEach( f => 
    {
        <label>@f[1]</label>
    } );
}

The error I get is with the <label>, "Invalid expression term '<'.

If it matters, my browser is IE9.

Felipe Oriani · Answer 1 · 2013-09-20T17:32:51.010

1

The problem is the ForEach is a method that accepts a lambda expression, so, you cannot pass a View (or a piece of html) code in this scope. I recommend you use a simple foreach loop.

@foreach(var field in fields) {
   <label>@field[1]</label>
}

If you have problems with this approach, you also can use the <text> razor tag.

@{

  foreach(var field in fields) {
    <text> 
       <label>@field[1]</label>
    </text>
  }

}

edited Sep 20 '13 at 17:32

answered Sep 19 '13 at 19:49

Felipe Oriani

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Yes the foreach works. But, you are saying Razor does not understand how to handle a lambda expression? It looks like you are correct, but do you know why? I know it is not the same, but I see code like @Html...(x => x...) all over the place. – Kelly Cline Sep 23 '13 at 21:57
The reason is, you cannot pass a razor context to a lambda expression of a specifique type. Maybe you can create a Razor Helper Method: http://stackoverflow.com/questions/14328303/how-to-pass-in-a-lambda-to-a-razor-helper-method – Felipe Oriani Sep 23 '13 at 22:48

Difference between Razor single statement and block

1 Answers1