Styjun

Inside Out and Back to Front

"move up the school" meaning

What is the minimum wait before I may I re-enter the USA after a 90 day visit on the Visa B-2 Program?

Does a hash function have a Upper bound on input length?

Why should fork() have been designed to return a file descriptor?

Time war story - soldier name lengthens as he travels further from the battle front

Can a person become a professor in English without having a Bachelor degree in English?

Book in which the "mountain" in the distance was a hole in the flat world

Do pedestrians imitate automotive traffic?

How far off did Apollo 11 land?

Could Europeans in Europe demand protection under UN Declaration on the Rights of Indigenous Peoples?

Nilpotent elements of Lie algebra and unipotent groups

How to declare an array without specifying its size, but with an initializer inside a class in C++?

Making an example from 'Clean Code' more functional

A bicolour masyu

Do you need to have the original move to take a "Replaces:" move?

Alignment problem with a mathematical equation in a presentation in beamer

Soft constraints and hard constraints

Remove side menu(right side) from finder

What would be the effects of (relatively) widespread precognition on the stock market?

French equivalents of "X puts the smile back on her face"

How to hook up Korg EX-8000 to a computer w/o a keyboard?

Why didn't Balak request Bilam to bless his own people?

Why are flying carpets banned while flying brooms are not?

Check if Combo box is empty C#

How do I calculate someone's age in C#?What is the difference between String and string in C#?Hidden Features of C#?Cast int to enum in C#How do I enumerate an enum in C#?What are the correct version numbers for C#?How do I get a consistent byte representation of strings in C# without manually specifying an encoding?making a combo box editableType Checking: typeof, GetType, or is?How to Create combo box to auto fill while user type the spelings inside the combo Box in c#

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;

0

I am trying to check if a combo box is empty using C# in a Windows Application Form. Below are two possible ways:

1. if (string.IsNullOrEmpty(comboBox1.Text))


2. if (comboBox1.SelectedIndex == -1)

In order to ensure that the user would ONLY select a value from the drop down and NOT write it s own answer, which is the best approach?
From my research the second method (if (comboBox1.SelectedIndex == -1)) will satisfy my needs. Am l right?

c# winforms combobox

share|improve this question

edited Mar 26 at 12:43

Michal Ciechan

8,8731010 gold badges5757 silver badges9898 bronze badges

asked Mar 26 at 12:37

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If dropdown lits has empty string as an option the 1st possibility is wrong (user can deliberatly choose the empty option). In case of 2nd option I'd rather put it as if (comboBox1.SelectedIndex < 0) in order not to use magic constant -1
  
  – Dmitry Bychenko
  Mar 26 at 12:41
  
  

  
  
  
  

add a comment | 

0

I am trying to check if a combo box is empty using C# in a Windows Application Form. Below are two possible ways:

1. if (string.IsNullOrEmpty(comboBox1.Text))


2. if (comboBox1.SelectedIndex == -1)

In order to ensure that the user would ONLY select a value from the drop down and NOT write it s own answer, which is the best approach?
From my research the second method (if (comboBox1.SelectedIndex == -1)) will satisfy my needs. Am l right?

c# winforms combobox

share|improve this question

edited Mar 26 at 12:43

Michal Ciechan

8,8731010 gold badges5757 silver badges9898 bronze badges

asked Mar 26 at 12:37

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If dropdown lits has empty string as an option the 1st possibility is wrong (user can deliberatly choose the empty option). In case of 2nd option I'd rather put it as if (comboBox1.SelectedIndex < 0) in order not to use magic constant -1
  
  – Dmitry Bychenko
  Mar 26 at 12:41
  
  

  
  
  
  

add a comment | 

I am trying to check if a combo box is empty using C# in a Windows Application Form. Below are two possible ways:

1. if (string.IsNullOrEmpty(comboBox1.Text))


2. if (comboBox1.SelectedIndex == -1)

In order to ensure that the user would ONLY select a value from the drop down and NOT write it s own answer, which is the best approach?
From my research the second method (if (comboBox1.SelectedIndex == -1)) will satisfy my needs. Am l right?

c# winforms combobox

share|improve this question

edited Mar 26 at 12:43

Michal Ciechan

8,8731010 gold badges5757 silver badges9898 bronze badges

asked Mar 26 at 12:37

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

share|improve this question

edited Mar 26 at 12:43

Michal Ciechan

8,8731010 gold badges5757 silver badges9898 bronze badges

asked Mar 26 at 12:37

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

share|improve this question

edited Mar 26 at 12:43

Michal Ciechan

8,8731010 gold badges5757 silver badges9898 bronze badges

asked Mar 26 at 12:37

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

edited Mar 26 at 12:43

Michal Ciechan

8,8731010 gold badges5757 silver badges9898 bronze badges

edited Mar 26 at 12:43

Michal Ciechan

8,8731010 gold badges5757 silver badges9898 bronze badges

asked Mar 26 at 12:37

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

asked Mar 26 at 12:37

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

3 Answers
3

active

oldest

votes

1

If your concern is only making sure that users choose an item from the list available, simply change your combobox's DropDownStyle to DropDownList

or if you want to allow them to type but then ensure it is on the list, you can do something like this:

var txt = comboBox1.Text;

if(string.IsNullOrEmpty())
 return;

var test = comboBox1.Items?.OfType<string>().ToList().Any(x => x?.Trim() == txt?.Trim());

so if test is false, it means what they have selected/typed does not exist in list of available items

share|improve this answer

edited Mar 26 at 12:49

answered Mar 26 at 12:42

Amir No-FamilyAmir No-Family

54744 silver badges1313 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  It would prohibit making changes to the combo in code...
  
  – Werner
  Mar 26 at 12:45
  
  

  
  
  
  

add a comment | 

0

for combobox you can use this code below to check if it's empty or not

 if(comboBox1.Items.Count == 0 )
 
 // your code
 

share|improve this answer

answered Mar 26 at 12:47

sayah imadsayah imad

53144 silver badges1515 bronze badges

add a comment | 

0

This is what i try and it 's work. Feel free to comment:

if (comboBox1.SelectedIndex > -1 )

share|improve this answer

answered Mar 26 at 13:58

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

add a comment | 

Your Answer

StackExchange.ifUsing("editor", function ()
StackExchange.using("externalEditor", function ()
StackExchange.using("snippets", function ()
StackExchange.snippets.init();
);
);
, "code-snippets");

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "1"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55357385%2fcheck-if-combo-box-is-empty-c-sharp%23new-answer', 'question_page');

);

Post as a guest

Name

Email

Required, but never shown

1

If your concern is only making sure that users choose an item from the list available, simply change your combobox's DropDownStyle to DropDownList

or if you want to allow them to type but then ensure it is on the list, you can do something like this:

var txt = comboBox1.Text;

if(string.IsNullOrEmpty())
 return;

var test = comboBox1.Items?.OfType<string>().ToList().Any(x => x?.Trim() == txt?.Trim());

so if test is false, it means what they have selected/typed does not exist in list of available items

share|improve this answer

edited Mar 26 at 12:49

answered Mar 26 at 12:42

Amir No-FamilyAmir No-Family

54744 silver badges1313 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  It would prohibit making changes to the combo in code...
  
  – Werner
  Mar 26 at 12:45
  
  

  
  
  
  

add a comment | 

1

If your concern is only making sure that users choose an item from the list available, simply change your combobox's DropDownStyle to DropDownList

or if you want to allow them to type but then ensure it is on the list, you can do something like this:

var txt = comboBox1.Text;

if(string.IsNullOrEmpty())
 return;

var test = comboBox1.Items?.OfType<string>().ToList().Any(x => x?.Trim() == txt?.Trim());

so if test is false, it means what they have selected/typed does not exist in list of available items

share|improve this answer

edited Mar 26 at 12:49

answered Mar 26 at 12:42

Amir No-FamilyAmir No-Family

54744 silver badges1313 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  It would prohibit making changes to the combo in code...
  
  – Werner
  Mar 26 at 12:45
  
  

  
  
  
  

add a comment | 

If your concern is only making sure that users choose an item from the list available, simply change your combobox's DropDownStyle to DropDownList

or if you want to allow them to type but then ensure it is on the list, you can do something like this:

var txt = comboBox1.Text;

if(string.IsNullOrEmpty())
 return;

var test = comboBox1.Items?.OfType<string>().ToList().Any(x => x?.Trim() == txt?.Trim());

so if test is false, it means what they have selected/typed does not exist in list of available items

share|improve this answer

edited Mar 26 at 12:49

answered Mar 26 at 12:42

Amir No-FamilyAmir No-Family

54744 silver badges1313 bronze badges

var txt = comboBox1.Text;

if(string.IsNullOrEmpty())
 return;

var test = comboBox1.Items?.OfType<string>().ToList().Any(x => x?.Trim() == txt?.Trim());

share|improve this answer

edited Mar 26 at 12:49

answered Mar 26 at 12:42

Amir No-FamilyAmir No-Family

54744 silver badges1313 bronze badges

answered Mar 26 at 12:42

Amir No-FamilyAmir No-Family

54744 silver badges1313 bronze badges

answered Mar 26 at 12:42

Amir No-FamilyAmir No-Family

54744 silver badges1313 bronze badges

0

for combobox you can use this code below to check if it's empty or not

 if(comboBox1.Items.Count == 0 )
 
 // your code
 

share|improve this answer

answered Mar 26 at 12:47

sayah imadsayah imad

53144 silver badges1515 bronze badges

add a comment | 

0

for combobox you can use this code below to check if it's empty or not

 if(comboBox1.Items.Count == 0 )
 
 // your code
 

share|improve this answer

answered Mar 26 at 12:47

sayah imadsayah imad

53144 silver badges1515 bronze badges

add a comment | 

for combobox you can use this code below to check if it's empty or not

 if(comboBox1.Items.Count == 0 )
 
 // your code
 

share|improve this answer

answered Mar 26 at 12:47

sayah imadsayah imad

53144 silver badges1515 bronze badges

 if(comboBox1.Items.Count == 0 )
 
 // your code
 

share|improve this answer

answered Mar 26 at 12:47

sayah imadsayah imad

53144 silver badges1515 bronze badges

answered Mar 26 at 12:47

sayah imadsayah imad

53144 silver badges1515 bronze badges

answered Mar 26 at 12:47

sayah imadsayah imad

53144 silver badges1515 bronze badges

0

This is what i try and it 's work. Feel free to comment:

if (comboBox1.SelectedIndex > -1 )

share|improve this answer

answered Mar 26 at 13:58

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

add a comment | 

0

This is what i try and it 's work. Feel free to comment:

if (comboBox1.SelectedIndex > -1 )

share|improve this answer

answered Mar 26 at 13:58

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

add a comment | 

This is what i try and it 's work. Feel free to comment:

if (comboBox1.SelectedIndex > -1 )

share|improve this answer

answered Mar 26 at 13:58

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

if (comboBox1.SelectedIndex > -1 )

share|improve this answer

answered Mar 26 at 13:58

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

answered Mar 26 at 13:58

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges

answered Mar 26 at 13:58

Error 1004Error 1004

5,14222 gold badges88 silver badges2525 bronze badges