If value is null put an empty string on razor template?

Question

I have a razor template like below. I want to check if the value in the input field is null, put a empty string, if the @UIManager.Member.EMail has a value, put its value. How can I do that?

Normal Input:

<input name="EMail" id="SignUpEMail" type="text" class="Input" 
       value="@UIManager.Member.EMail" validate="RequiredField" />

Razor Syntax Attempt:

<input name="EMail" id="SignUpEMail" type="text" class="Input" validate="RequiredField"
       value="@(UIManager.Member == null) ? string.Empty : UIManager.Member.EMail" />

The value is shown in the input field is:

True ? string.Empty : UIBusinessManager.MemberCandidate.EMail

as long as UIManager and UIManager.Member are non-null, this should already work... can you clarify? — Marc Gravell, Aug 17 '11 at 08:25
Actually @UIManager.Member is initially null. It gets its value after a postback operation. So it doesnt work, you're right. How to check it so ? — Barış Velioğlu, Aug 17 '11 at 08:33

score 67 · Accepted Answer · answered Aug 17 '11 at 08:41

If sounds like you just want:

@(UIManager.Member == null ? "" : UIManager.Member.Email)

Note the locations of the brackets is critical; with razor, @(....) defines an explicit range to the code - hence anything outside the brackets is treated as markup (not code).

score 27 · Answer 2 · answered Sep 27 '16 at 17:38

27

This is exactly what the NullDisplayText property on [DisplayFormat] attribute is for.

Add this directly on your model:

[DisplayFormat(NullDisplayText="", ApplyFormatInEditMode=true)]
public string EMail { get; set; }

answered Sep 27 '16 at 17:38

KyleMit

30,350
66
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I believe this is the best answer If an approach is considered. Much cleaner and easier to implement. – Sangram Nandkhile Dec 16 '16 at 08:36
1

+1 Note: I've found it necessary to do `@Html.DisplayFor(m => m.Email)` since that attribute gets ignored by `@Model.Email`. – MarredCheese Sep 09 '20 at 17:03

score 21 · Answer 3 · edited Jan 14 '16 at 20:01

21

To Check some property of a model in cshtml.

@if(!string.IsNullOrEmpty(Model.CUSTOM_PROPERTY))
{
    <p>@Model.CUSTOM_PROPERTY</p>
}
else
{
    <p> - </p>
}

so best way to do this:

@(Model.CUSTOM_PROPERTY ?? "-")

edited Jan 14 '16 at 20:01

Amadeus Sanchez

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answered May 08 '14 at 19:56

Ghazni

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8
16

So glad we can do that now, like in JS. – gdbj Feb 07 '18 at 22:29

score 3 · Answer 4 · answered Apr 08 '17 at 14:42

3

Use the null conditional operator:

@UIManager.Member?.Email

answered Apr 08 '17 at 14:42

Michael Diomin

530
3
13

2

It should be @(UIManager.Member?.Email) – timmz Jul 02 '17 at 23:44
3

To answer the question it should be: @(UIManager.Member?.Email ?? string.Empty) – maets Sep 09 '19 at 20:14

score 0 · Answer 5 · edited May 17 '22 at 00:15

0

$" ({UIManager.Member.FirstOrDefault()?.EMail})" ?? "N/A"

edited May 17 '22 at 00:15

Jeremy Caney

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answered May 10 '22 at 09:08

Sunitha

1
2

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Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community May 11 '22 at 15:08

If value is null put an empty string on razor template?

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