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String.Equals Method (String, String, StringComparison)

Determines whether two specified String objects have the same value. A parameter specifies the culture, case, and sort rules used in the comparison.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

[SecuritySafeCriticalAttribute]
public static bool Equals(
	string a,
	string b,
	StringComparison comparisonType
)

Parameters

a
Type: System.String
The first string to compare, or null.
b
Type: System.String
The second string to compare, or null.
comparisonType
Type: System.StringComparison
One of the enumeration values that specifies the rules for the comparison.

Return Value

Type: System.Boolean
true if the value of the a parameter is equal to the value of the b parameter; otherwise, false.

ExceptionCondition
ArgumentException

comparisonType is not a StringComparison value.

The comparisonType parameter indicates whether the comparison should use the current or invariant culture, honor or ignore the case of the two strings being compared, or use word or ordinal sort rules.

The following code example uses three versions of the Equals method to determine whether a String object and a StringBuilder object are equal.


// Sample for String.Equals(Object)
//            String.Equals(String)
//            String.Equals(String, String)
using System;
using System.Text;

class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      StringBuilder sb = new StringBuilder("abcd");
      String str1 = "abcd";
      String str2 = null;
      Object o2 = null;

      outputBlock.Text += "\n";
      outputBlock.Text += String.Format(" *  The value of String str1 is '{0}'.", str1) + "\n";
      outputBlock.Text += String.Format(" *  The value of StringBuilder sb is '{0}'.", sb.ToString()) + "\n";

      outputBlock.Text += "\n";
      outputBlock.Text += String.Format("1a) String.Equals(Object). Object is a StringBuilder, not a String.") + "\n";
      outputBlock.Text += String.Format("    Is str1 equal to sb?: {0}", str1.Equals(sb)) + "\n";

      outputBlock.Text += "\n";
      outputBlock.Text += "1b) String.Equals(Object). Object is a String." + "\n";
      str2 = sb.ToString();
      o2 = str2;
      outputBlock.Text += String.Format(" *  The value of Object o2 is '{0}'.", o2) + "\n";
      outputBlock.Text += String.Format("    Is str1 equal to o2?: {0}", str1.Equals(o2)) + "\n";

      outputBlock.Text += "\n";
      outputBlock.Text += " 2) String.Equals(String)" + "\n";
      outputBlock.Text += String.Format(" *  The value of String str2 is '{0}'.", str2) + "\n";
      outputBlock.Text += String.Format("    Is str1 equal to str2?: {0}", str1.Equals(str2)) + "\n";

      outputBlock.Text += "\n";
      outputBlock.Text += String.Format(" 3) String.Equals(String, String)") + "\n";
      outputBlock.Text += String.Format("    Is str1 equal to str2?: {0}", String.Equals(str1, str2)) + "\n";
   }
}
/*
This example produces the following results:

 *  The value of String str1 is 'abcd'.
 *  The value of StringBuilder sb is 'abcd'.

1a) String.Equals(Object). Object is a StringBuilder, not a String.
    Is str1 equal to sb?: False

1b) String.Equals(Object). Object is a String.
 *  The value of Object o2 is 'abcd'.
    Is str1 equal to o2?: True

 2) String.Equals(String)
 *  The value of String str2 is 'abcd'.
    Is str1 equal to str2?: True

 3) String.Equals(String, String)
    Is str1 equal to str2?: True
*/


Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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