String.StartsWith Method (String, Boolean, CultureInfo)

 

Determines whether the beginning of this string instance matches the specified string when compared using the specified culture.

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

Public Function StartsWith (
	value As String,
	ignoreCase As Boolean,
	culture As CultureInfo
) As Boolean

Parameters

value
Type: System.String

The string to compare.

ignoreCase
Type: System.Boolean

true to ignore case during the comparison; otherwise, false.

culture
Type: System.Globalization.CultureInfo

Cultural information that determines how this string and value are compared. If culture is null, the current culture is used.

Return Value

Type: System.Boolean

true if the value parameter matches the beginning of this string; otherwise, false.

Exception Condition
ArgumentNullException

value is null.

This method compares the value parameter to the substring at the beginning of this string that is the same length as value, and returns a value that indicates whether they are equal. To be equal, value must be an empty string (String.Empty), must be a reference to this same instance, or must match the beginning of this instance.

This method performs a comparison using the specified casing and culture.

The following example determines whether a string occurs at the beginning of another string. The StartsWith method is called several times using case sensitivity, case insensitivity, and different cultures that influence the results of the search.

' This code example demonstrates the 
' System.String.StartsWith(String, ..., CultureInfo) method.

Imports System
Imports System.Threading
Imports System.Globalization

Class Sample
    Public Shared Sub Main() 
        Dim msg1 As String = "Search for the target string ""{0}"" in the string ""{1}""." & vbCrLf
        Dim msg2 As String = "Using the {0} - ""{1}"" culture:"
        Dim msg3 As String = "  The string to search ends with the target string: {0}"
        Dim result As Boolean = False
        Dim ci As CultureInfo

        ' Define a target string to search for.
        ' U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
        Dim capitalARing As String = "Å"

        ' Define a string to search. 
        ' The result of combining the characters LATIN SMALL LETTER A and COMBINING 
        ' RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
        ' LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
        Dim aRingXYZ As String = "å" & "xyz"

        ' Clear the screen and display an introduction.
        Console.Clear()

        ' Display the string to search for and the string to search.
        Console.WriteLine(msg1, capitalARing, aRingXYZ)

        ' Search using English-United States culture.
        ci = New CultureInfo("en-US")
        Console.WriteLine(msg2, ci.DisplayName, ci.Name)

        Console.WriteLine("Case sensitive:")
        result = aRingXYZ.StartsWith(capitalARing, False, ci)
        Console.WriteLine(msg3, result)

        Console.WriteLine("Case insensitive:")
        result = aRingXYZ.StartsWith(capitalARing, True, ci)
        Console.WriteLine(msg3, result)
        Console.WriteLine()

        ' Search using Swedish-Sweden culture.
        ci = New CultureInfo("sv-SE")
        Console.WriteLine(msg2, ci.DisplayName, ci.Name)

        Console.WriteLine("Case sensitive:")
        result = aRingXYZ.StartsWith(capitalARing, False, ci)
        Console.WriteLine(msg3, result)

        Console.WriteLine("Case insensitive:")
        result = aRingXYZ.StartsWith(capitalARing, True, ci)
        Console.WriteLine(msg3, result)

    End Sub 'Main
End Class 'Sample

'
'Note: This code example was executed on a console whose user interface 
'culture is "en-US" (English-United States).
'
'Search for the target string "Å" in the string "a°xyz".
'
'Using the English (United States) - "en-US" culture:
'Case sensitive:
'  The string to search ends with the target string: False
'Case insensitive:
'  The string to search ends with the target string: True
'
'Using the Swedish (Sweden) - "sv-SE" culture:
'Case sensitive:
'  The string to search ends with the target string: False
'Case insensitive:
'  The string to search ends with the target string: False
'

.NET Framework
Available since 2.0
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