How to ignorecase when using string.text.contains?

Question

I am trying to figure out how to check if a string contains another while ignoring case using .text.contains.

As it stands right now If I do this:

 Dim myhousestring As String = "My house is cold"
    If txt.Text.Contains(myhousestring) Then
    Messagebox.Show("Found it")
    End If

It will only return a match if it is the exact same case. So if the user typed "my house is cold", it would not be a match.

How can I do this? If it is not possible I could probably just use regex instead with ignorecase. Any help would be appreciated.

Marcel Gosselin · Accepted Answer · 2012-12-28 03:35:06Z

46

According to Microsoft you can do case-insensitive searches in strings with IndexOf instead of Contains. So when the result of the IndexOf method returns a value greater than -1, it means the second string is a substring of the first one.

Dim myhousestring As String = "My house is cold"
If txt.Text.IndexOf(myhousestring, 0, StringComparison.CurrentCultureIgnoreCase) > -1 Then
    Messagebox.Show("Found it")
End If

You can also use other case-insensitive variants of StringComparison.

edited Dec 28, 2012 at 3:35

answered Dec 28, 2012 at 3:29

Marcel Gosselin

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1 Comment

user1632018 Over a year ago

ahh, this is exactly what I was looking for. I knew their was was another string method that could be used to compare strings. Thanks alot. I appreciate it.

Catherine · Accepted Answer · 2016-02-19 02:04:36Z

15

I'm not a vb.net programmer, but according to Microsoft, you can get the lowercase/uppercase value of the text using the string methods ToUpper() or ToLower(). You can then compare that with "my house is cold" or "MY HOUSE IS COLD".

Dim myhousestring As String = "MY HOUSE IS COLD"
If txt.Text.ToUpper.Contains(myhousestring) Then
    Messagebox.Show("Found it")
End If

edited Feb 19, 2016 at 2:04

Catherine

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answered Dec 28, 2012 at 3:27

AI Generated Response

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2 Comments

user4951 Over a year ago

I like this solution better.

jt000 Over a year ago

This causes issues w/ globalization specifically w/ Turkish i. I'd be careful w/ this method.

Adam Pine · Accepted Answer · 2017-08-16 19:24:48Z

6

Personally I just used:

item.Text.ToLower().Contains("my house is cold")

you could just as well use ToUpper as well.

Caveat: If you are comparing Turkish, or other languages, the ToLower() and ToUpper() also take an option parameter, for "CultureInfo" allowing you to ensure that different languages are handled correctly. You can use an above solution, or you can follow the steps from Microsoft's ToLower Documentation, to add in CultureInfo, to get ToLower context on which language you are about to try to manipulate.

ToLower() with CultureInfo documentation

ToUpper() with CultureInfo documentation

edited Aug 16, 2017 at 19:24

answered Jun 8, 2016 at 14:16

Adam Pine

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2 Comments

jt000 Over a year ago

This causes issues w/ globalization specifically w/ Turkish i. I'd be careful w/ this method.

Adam Pine Over a year ago

The question doesn't seem to mention that it needs to support Turkish... especially when we are comparing the text, with English... The Culture indifferent compare isn't going to translate from Turkish to English, and THEN compare, it's just going to compare the characters.

xcrookedxedge · Accepted Answer · 2017-03-27 10:55:22Z

3

I solved this problem with .toUpper

For example:

Dim UGroup as String = dr.Item(2).ToString().ToUpper
Dim s as String = ds.Item(1).ToString.ToUpper

If s.Contains(UGroup) then MsgBox("Well done!")
Else 
End Sub

Same procedure with .toLower

edited Mar 27, 2017 at 10:55

answered Mar 27, 2017 at 10:01

xcrookedxedge

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2 Comments

xcrookedxedge Over a year ago

Sorry it's a german word. Commata means Commas. So "," this is only importan in my code. But i deleted it to not spread confusion.

xcrookedxedge Over a year ago

Danke für das +1! I mean: Thank you for the +1

Pang · Accepted Answer · 2015-12-30 02:27:04Z

1

Or you can use RegularExpressions like this.

First, import the RegularExpressions:

Imports System.Text.RegularExpressions

then try this code:

Dim match As Match = Regex.Match(Textbox1.text,"My house is cold",RegexOptions.IgnoreCase)
If match.Success Then
   Msgbox(match.Value)
End If

edited Dec 30, 2015 at 2:27

Pang

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answered Dec 30, 2015 at 2:00

Muteb A.

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1 Comment

beppe9000 Over a year ago

this looks like an overkill

Elias · Accepted Answer · 2013-10-18 22:56:16Z

0

this is how I solved my problem of making String.Contains become case insensitive.

Dim s as string = "My HoUsE iS cOlD".ToUpper

If s.Contains("MY HOUSE IS COLD") Then Exit Sub

For my particular issue, the string that I was checking was housed within a TextBox.

I hope this helps.

answered Oct 18, 2013 at 22:56

Elias

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Comments

beppe9000 · Accepted Answer · 2016-07-23 13:50:07Z

0

What about this?

<Runtime.CompilerServices.Extension>
Function InStr(s As String, find As String) As Boolean
    Return s.ToLower.Contains(find.ToLower)
End Function

answered Jul 23, 2016 at 13:50

beppe9000

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Comments

mhatch · Accepted Answer · 2017-06-23 13:47:14Z

0

use the InStr example. "contains" fails if ether compare is nothing.

'if we found something...

If InStr(1, value, search, vbTextCompare) > 0 Then

Beep

End If   

                                               '

edited Jun 23, 2017 at 13:47

mhatch

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answered Jun 23, 2017 at 13:36

Sandy

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1 Comment

Tom Over a year ago

InStr's first parameter isn't needed in this case, and you might want to match up your input parameters with the questions. I also don't think this is case-insensative according to MSDN?

supwat · Accepted Answer · 2020-10-10 13:37:12Z

0

I use below code to search/confirm if string in TEXTBOX1 was in "c:\testsearch.txt".

    Imports System.IO

Private Function sinf(path As String, match As String) As Boolean 
    Dim s As String = File.ReadAllText(path).ToLower
    Return s.Contains(match.ToLower)
End Function

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim st As String
    st = TextBox1.Text
    If sinf("c:\testsearch.txt", st) = True Then 
        MsgBox("Found if")
    Else
        MsgBox("Try again")
    End If
End Sub

answered Oct 10, 2020 at 13:37

supwat

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