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:

 D         


        

Answer 1

What about this?

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

Answer 2

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

Answer 3

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   

                                               '

Answer 4

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.

Answer 5

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.

Answer 6

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