String.Equals Method (String, String, StringComparison)
Microsoft Silverlight will reach end of support after October 2021. Learn more.
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)
Syntax
'Declaration
<SecuritySafeCriticalAttribute> _
Public Shared Function Equals ( _
a As String, _
b As String, _
comparisonType As StringComparison _
) As Boolean
[SecuritySafeCriticalAttribute]
public static bool Equals(
string a,
string b,
StringComparison comparisonType
)
Parameters
- a
Type: System.String
The first string to compare, or nulla null reference (Nothing in Visual Basic).
- b
Type: System.String
The second string to compare, or nulla null reference (Nothing in Visual Basic).
- 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.
Remarks
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.
Examples
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)
Imports System.Text
Class Example
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
Dim sb As New StringBuilder("abcd")
Dim str1 As [String] = "abcd"
Dim str2 As [String] = Nothing
Dim o2 As [Object] = Nothing
outputBlock.Text &= vbCrLf
outputBlock.Text += String.Format(" * The value of String str1 is '{0}'.", str1) & vbCrLf
outputBlock.Text += String.Format(" * The value of StringBuilder sb is '{0}'.", sb.ToString()) & vbCrLf
outputBlock.Text &= vbCrLf
outputBlock.Text += String.Format("1a) String.Equals(Object). Object is a StringBuilder, not a String.") & vbCrLf
outputBlock.Text += String.Format(" Is str1 equal to sb?: {0}", str1.Equals(sb)) & vbCrLf
outputBlock.Text &= vbCrLf
outputBlock.Text &= "1b) String.Equals(Object). Object is a String." & vbCrLf
str2 = sb.ToString()
o2 = str2
outputBlock.Text += String.Format(" * The value of Object o2 is '{0}'.", o2) & vbCrLf
outputBlock.Text += String.Format(" Is str1 equal to o2?: {0}", str1.Equals(o2)) & vbCrLf
outputBlock.Text &= vbCrLf
outputBlock.Text &= " 2) String.Equals(String)" & vbCrLf
outputBlock.Text += String.Format(" * The value of String str2 is '{0}'.", str2) & vbCrLf
outputBlock.Text += String.Format(" Is str1 equal to str2?: {0}", str1.Equals(str2)) & vbCrLf
outputBlock.Text &= vbCrLf
outputBlock.Text += String.Format(" 3) String.Equals(String, String)") & vbCrLf
outputBlock.Text += String.Format(" Is str1 equal to str2?: {0}", [String].Equals(str1, str2)) & vbCrLf
End Sub 'Main
End Class 'Sample
'
'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
'
// 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
*/
Version Information
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
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.