CompareInfo.IndexOf Method (String, String)

Searches for the specified substring and returns the zero-based index of the first occurrence within the entire source string.

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

Syntax

'Declaration
Public Overridable Function IndexOf ( _
    source As String, _
    value As String _
) As Integer
public virtual int IndexOf(
    string source,
    string value
)

Parameters

Return Value

Type: System.Int32
The zero-based index of the first occurrence of value within the entire source, if found; otherwise, -1.

Exceptions

Exception Condition
ArgumentNullException

source is nulla null reference (Nothing in Visual Basic).

-or-

value is nulla null reference (Nothing in Visual Basic).

Remarks

The source string is searched forward starting at the beginning of the string and ending at the end of the string.

This overload performs a culture-sensitive search. A Unicode value representing a precomposed character, such as the ligature "Æ" (U+00C6), might be considered equivalent to any occurrence of the character's components in the correct sequence, such as "AE" (U+0041, U+0045), depending on the culture. To perform an ordinal (culture-insensitive) search, where the Unicode values are compared, the application should use one of the overloads that accepts a CompareOptions value as a parameter and use the Ordinal value.

Examples

The following example determines the indexes of the first and last occurrences of a character or a substring within a string.

Imports System.Globalization

Public Class Example

   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      ' Creates CompareInfo for the InvariantCulture.
      Dim myComp As CompareInfo = CultureInfo.InvariantCulture.CompareInfo

      ' Searches for the ligature Æ.
      Dim myStr As [String] = "Is AE or ae the same as Æ or æ?"
      outputBlock.Text &= vbCrLf
      outputBlock.Text += String.Format("No options    : {0}", myStr) & vbCrLf
      PrintMarker(outputBlock, "           AE : ", myComp.IndexOf(myStr, "AE"), myComp.LastIndexOf(myStr, "AE"))
      PrintMarker(outputBlock, "           ae : ", myComp.IndexOf(myStr, "ae"), myComp.LastIndexOf(myStr, "ae"))
      PrintMarker(outputBlock, "            Æ : ", myComp.IndexOf(myStr, "Æ"c), myComp.LastIndexOf(myStr, "Æ"c))
      PrintMarker(outputBlock, "            æ : ", myComp.IndexOf(myStr, "æ"c), myComp.LastIndexOf(myStr, "æ"c))
      outputBlock.Text += String.Format("Ordinal       : {0}", myStr) & vbCrLf
      PrintMarker(outputBlock, "           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", CompareOptions.Ordinal))
      PrintMarker(outputBlock, "           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", CompareOptions.Ordinal))
      PrintMarker(outputBlock, "            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.Ordinal))
      PrintMarker(outputBlock, "            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.Ordinal))
      outputBlock.Text += String.Format("IgnoreCase    : {0}", myStr) & vbCrLf
      PrintMarker(outputBlock, "           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", CompareOptions.IgnoreCase))
      PrintMarker(outputBlock, "           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", CompareOptions.IgnoreCase))
      PrintMarker(outputBlock, "            Æ : ", myComp.IndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Æ"c, CompareOptions.IgnoreCase))
      PrintMarker(outputBlock, "            æ : ", myComp.IndexOf(myStr, "æ"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "æ"c, CompareOptions.IgnoreCase))

      ' Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is " & ChrW(&H55) & ChrW(&H308) & " or " & ChrW(&H75) & ChrW(&H308) & " the same as " & ChrW(&HDC) & " or " & ChrW(&HFC) & "?"
      outputBlock.Text &= vbCrLf
      outputBlock.Text += String.Format("No options    : {0}", myStr) & vbCrLf
      PrintMarker(outputBlock, "           U" & ChrW(&H308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H308)), myComp.LastIndexOf(myStr, "U" & ChrW(&H308)))
      PrintMarker(outputBlock, "           u" & ChrW(&H308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H308)), myComp.LastIndexOf(myStr, "u" & ChrW(&H308)))
      PrintMarker(outputBlock, "            Ü : ", myComp.IndexOf(myStr, "Ü"c), myComp.LastIndexOf(myStr, "Ü"c))
      PrintMarker(outputBlock, "            ü : ", myComp.IndexOf(myStr, "ü"c), myComp.LastIndexOf(myStr, "ü"c))
      outputBlock.Text += String.Format("Ordinal       : {0}", myStr) & vbCrLf
      PrintMarker(outputBlock, "           U" & ChrW(&H308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U" & ChrW(&H308), CompareOptions.Ordinal))
      PrintMarker(outputBlock, "           u" & ChrW(&H308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H308), CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u" & ChrW(&H308), CompareOptions.Ordinal))
      PrintMarker(outputBlock, "            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.Ordinal))
      PrintMarker(outputBlock, "            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.Ordinal))
      outputBlock.Text += String.Format("IgnoreCase    : {0}", myStr) & vbCrLf
      PrintMarker(outputBlock, "           U" & ChrW(&H308) & " : ", myComp.IndexOf(myStr, "U" & ChrW(&H308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U" & ChrW(&H308), CompareOptions.IgnoreCase))
      PrintMarker(outputBlock, "           u" & ChrW(&H308) & " : ", myComp.IndexOf(myStr, "u" & ChrW(&H308), CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u" & ChrW(&H308), CompareOptions.IgnoreCase))
      PrintMarker(outputBlock, "            Ü : ", myComp.IndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "Ü"c, CompareOptions.IgnoreCase))
      PrintMarker(outputBlock, "            ü : ", myComp.IndexOf(myStr, "ü"c, CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ü"c, CompareOptions.IgnoreCase))

   End Sub 'Main

   Public Shared Sub PrintMarker(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal Prefix As [String], ByVal First As Integer, ByVal Last As Integer)

      ' Determines the size of the array to create.
      Dim mySize As Integer
      If Last > First Then
         mySize = Last
      Else
         mySize = First
      End If

      If mySize > -1 Then

         ' Creates an array of Char to hold the markers.
         Dim myCharArr(mySize + 1) As [Char]

         ' Inserts the appropriate markers.
         If First > -1 Then
            myCharArr(First) = "f"c
         End If
         If Last > -1 Then
            myCharArr(Last) = "l"c
         End If
         If First = Last Then
            myCharArr(First) = "b"c
         End If
         ' Displays the array of Char as a String.
         outputBlock.Text += String.Format("{0}{1}", Prefix, New [String](myCharArr)) & vbCrLf

      Else
         outputBlock.Text &= Prefix & vbCrLf

      End If

   End Sub 'PrintMarker

End Class 'SamplesCompareInfo 


'This code produces the following output.
'
'No options    : Is AE or ae the same as Æ or æ?
'           AE :    f                    l
'           ae :          f                   l
'            Æ :    f                    l
'            æ :          f                   l
'Ordinal       : Is AE or ae the same as Æ or æ?
'           AE :    b
'           ae :          b
'            Æ :                         b
'            æ :                              b
'IgnoreCase    : Is AE or ae the same as Æ or æ?
'           AE :    f                         l
'           ae :    f                         l
'            Æ :    f                         l
'            æ :    f                         l
'
'No options    : Is U" or u" the same as Ü or ü?
'           U" :    f                    l
'           u" :          f                   l
'            Ü :    f                    l
'            ü :          f                   l
'Ordinal       : Is U" or u" the same as Ü or ü?
'           U" :    b
'           u" :          b
'            Ü :                         b
'            ü :                              b
'IgnoreCase    : Is U" or u" the same as Ü or ü?
'           U" :    f                         l
'           u" :    f                         l
'            Ü :    f                         l
'            ü :    f                         l

using System;
using System.Globalization;

public class Example
{

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      outputBlock.Text += "\n";
      outputBlock.Text += String.Format("No options    : {0}", myStr) + "\n";
      PrintMarker(outputBlock, "           AE : ", myComp.IndexOf(myStr, "AE"), myComp.LastIndexOf(myStr, "AE"));
      PrintMarker(outputBlock, "           ae : ", myComp.IndexOf(myStr, "ae"), myComp.LastIndexOf(myStr, "ae"));
      PrintMarker(outputBlock, "            Æ : ", myComp.IndexOf(myStr, 'Æ'), myComp.LastIndexOf(myStr, 'Æ'));
      PrintMarker(outputBlock, "            æ : ", myComp.IndexOf(myStr, 'æ'), myComp.LastIndexOf(myStr, 'æ'));
      outputBlock.Text += String.Format("Ordinal       : {0}", myStr) + "\n";
      PrintMarker(outputBlock, "           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "AE", CompareOptions.Ordinal));
      PrintMarker(outputBlock, "           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "ae", CompareOptions.Ordinal));
      PrintMarker(outputBlock, "            Æ : ", myComp.IndexOf(myStr, 'Æ', CompareOptions.Ordinal), myComp.LastIndexOf(myStr, 'Æ', CompareOptions.Ordinal));
      PrintMarker(outputBlock, "            æ : ", myComp.IndexOf(myStr, 'æ', CompareOptions.Ordinal), myComp.LastIndexOf(myStr, 'æ', CompareOptions.Ordinal));
      outputBlock.Text += String.Format("IgnoreCase    : {0}", myStr) + "\n";
      PrintMarker(outputBlock, "           AE : ", myComp.IndexOf(myStr, "AE", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "AE", CompareOptions.IgnoreCase));
      PrintMarker(outputBlock, "           ae : ", myComp.IndexOf(myStr, "ae", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "ae", CompareOptions.IgnoreCase));
      PrintMarker(outputBlock, "            Æ : ", myComp.IndexOf(myStr, 'Æ', CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, 'Æ', CompareOptions.IgnoreCase));
      PrintMarker(outputBlock, "            æ : ", myComp.IndexOf(myStr, 'æ', CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, 'æ', CompareOptions.IgnoreCase));

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      outputBlock.Text += "\n";
      outputBlock.Text += String.Format("No options    : {0}", myStr) + "\n";
      PrintMarker(outputBlock, "           U\u0308 : ", myComp.IndexOf(myStr, "U\u0308"), myComp.LastIndexOf(myStr, "U\u0308"));
      PrintMarker(outputBlock, "           u\u0308 : ", myComp.IndexOf(myStr, "u\u0308"), myComp.LastIndexOf(myStr, "u\u0308"));
      PrintMarker(outputBlock, "            Ü : ", myComp.IndexOf(myStr, 'Ü'), myComp.LastIndexOf(myStr, 'Ü'));
      PrintMarker(outputBlock, "            ü : ", myComp.IndexOf(myStr, 'ü'), myComp.LastIndexOf(myStr, 'ü'));
      outputBlock.Text += String.Format("Ordinal       : {0}", myStr) + "\n";
      PrintMarker(outputBlock, "           U\u0308 : ", myComp.IndexOf(myStr, "U\u0308", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "U\u0308", CompareOptions.Ordinal));
      PrintMarker(outputBlock, "           u\u0308 : ", myComp.IndexOf(myStr, "u\u0308", CompareOptions.Ordinal), myComp.LastIndexOf(myStr, "u\u0308", CompareOptions.Ordinal));
      PrintMarker(outputBlock, "            Ü : ", myComp.IndexOf(myStr, 'Ü', CompareOptions.Ordinal), myComp.LastIndexOf(myStr, 'Ü', CompareOptions.Ordinal));
      PrintMarker(outputBlock, "            ü : ", myComp.IndexOf(myStr, 'ü', CompareOptions.Ordinal), myComp.LastIndexOf(myStr, 'ü', CompareOptions.Ordinal));
      outputBlock.Text += String.Format("IgnoreCase    : {0}", myStr) + "\n";
      PrintMarker(outputBlock, "           U\u0308 : ", myComp.IndexOf(myStr, "U\u0308", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "U\u0308", CompareOptions.IgnoreCase));
      PrintMarker(outputBlock, "           u\u0308 : ", myComp.IndexOf(myStr, "u\u0308", CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, "u\u0308", CompareOptions.IgnoreCase));
      PrintMarker(outputBlock, "            Ü : ", myComp.IndexOf(myStr, 'Ü', CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, 'Ü', CompareOptions.IgnoreCase));
      PrintMarker(outputBlock, "            ü : ", myComp.IndexOf(myStr, 'ü', CompareOptions.IgnoreCase), myComp.LastIndexOf(myStr, 'ü', CompareOptions.IgnoreCase));

   }

   public static void PrintMarker(System.Windows.Controls.TextBlock outputBlock, String Prefix, int First, int Last)
   {

      // Determines the size of the array to create.
      int mySize;
      if (Last > First)
         mySize = Last;
      else
         mySize = First;

      if (mySize > -1)
      {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize + 1];

         // Inserts the appropriate markers.
         if (First > -1)
            myCharArr[First] = 'f';
         if (Last > -1)
            myCharArr[Last] = 'l';
         if (First == Last)
            myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         outputBlock.Text += String.Format("{0}{1}", Prefix, new String(myCharArr)) + "\n";

      }
      else
         outputBlock.Text += Prefix + "\n";

   }

}


/*
This code produces the following output.

No options    : Is AE or ae the same as Æ or æ?
           AE :    f                    l
           ae :          f                   l
            Æ :    f                    l
            æ :          f                   l
Ordinal       : Is AE or ae the same as Æ or æ?
           AE :    b
           ae :          b
            Æ :                         b
            æ :                              b
IgnoreCase    : Is AE or ae the same as Æ or æ?
           AE :    f                         l
           ae :    f                         l
            Æ :    f                         l
            æ :    f                         l

No options    : Is U" or u" the same as Ü or ü?
           U" :    f                    l
           u" :          f                   l
            Ü :    f                    l
            ü :          f                   l
Ordinal       : Is U" or u" the same as Ü or ü?
           U" :    b
           u" :          b
            Ü :                         b
            ü :                              b
IgnoreCase    : Is U" or u" the same as Ü or ü?
           U" :    f                         l
           u" :    f                         l
            Ü :    f                         l
            ü :    f                         l

*/

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.