17

How to convert the string to uppercase before performing a compare, or is it possible to compare the string by ignoring the case 

 if (Convert.ToString(txt_SecAns.Text.Trim()).ToUpper() == 
     Convert.ToString(hidden_secans.Value).ToUpper())
abatishchev
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Murthy
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10 Answers10

32

use this:

var result = String.Compare("AA", "aa", StringComparison.OrdinalIgnoreCase);

String.Compare Method (String, String, Boolean)

Davide Piras
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20

Case-insensitive string comparison is done like this in C#:

string.Equals("stringa", "stringb", StringComparison.CurrentCultureIgnoreCase)

Watch out! this code is culture dependant; there are several other options available, see http://msdn.microsoft.com/en-us/library/system.stringcomparison.aspx.

Kolky
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    Using the Turkish culture this code can return false for `STRINGA` and `stringa`. It's very well possible that the OP wants that, but it's important to be aware that culture influences case insensitive comparisons – CodesInChaos Nov 23 '11 at 13:55
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    If you want it to be culture invariant than use this `string.Equals("stringa", "stringb", StringComparison.InvariantCultureIgnoreCase)` – Fischermaen Nov 23 '11 at 14:08
  • What's the difference between this and `StringComparison.OrdinalIgnoreCase`? – PatPeter Oct 13 '18 at 23:59
5

Well, you can use String.Equals(String,StringComparison) method. Just pass it StringComparison.InvariantCultureIgnoreCase or StringComparison.CurrentCultureIgnoreCase depending on your objectives...

Dmitry
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4

From MSDN:

String.Compare Method (String, String, Boolean):

public static int Compare(
    string strA,
    string strB,
    bool ignoreCase
)

so in your case:

if( String.Compare(txt_SecAns.Text.Trim(), hidden_secans.Value, true) == 0)
akoso
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3

Just like this:

if (string.Compare(txt_SecAns.Text.Trim(), hidden_secans.Value.ToString(), true) == 0)
{
    // DoSomething
}

The third parameter true tells string.Compare to ignore case.

Fischermaen
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3
txt_SecAns.Trim().Compare(hidden_secans.Trim(), StringComparison.CurrentCultureIgnoreCase)
Pike65
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3

string.Compare(string1, string2, true) == 0 will compare if the two strings are equal ignoring case

JohnathanKong
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3

Use StringComparison.CurrentCultureIgnoreCase:

if (txt_SecAns.Text.Trim().Equals(hidden_secans.Value.ToString(), StringComparison.CurrentCultureIgnoreCase))
Michał Powaga
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3
String.Compare(str1, str2, true);
Tudor
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  • I'd prefer a method that explicitly specifies the culture. It's not obvious that this uses the current culture. – CodesInChaos Nov 23 '11 at 13:59
  • Yes, this version uses the current culture according to MSDN. There is an overload with a fourth parameter that lets you specify the culture explicitly. – Tudor Nov 23 '11 at 14:07
2

I would personaly compare with a proper culture like everyone here, but something hasn't been suggested :

public bool CompareStrings(string stringA, string StringB)
{
    return stringA.ToLower() == stringB.ToLower();
}
Tipx
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