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String.StartsWith Method (String)

Determines whether the beginning of this string instance matches the specified string.

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

'Declaration
Public Function StartsWith ( _
	value As String _
) As Boolean

Parameters

value
Type: System.String
The string to compare.

Return Value

Type: System.Boolean
true if value matches the beginning of this string; otherwise, false.

ExceptionCondition
ArgumentNullException

value is Nothing.

This method compares value to the substring at the beginning of this instance that is the same length as value, and returns an indication 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 word (case-sensitive and culture-sensitive) comparison using the current culture.

Notes to Callers

As explained in Best Practices for Using Strings in the .NET Framework, we recommend that you avoid calling string comparison methods that substitute default values and instead call methods that require parameters to be explicitly specified. To determine whether a string begins with a particular substring by using the string comparison rules of the current culture, call the StartsWith(String, StringComparison) method overload with a value of StringComparison.CurrentCulture for its comparisonType parameter.

The following example demonstrates how you can use the StartsWith method.


Imports System

Public Class EndsWithTest

    Public Shared Sub Main()
        Dim strSource As String() = {"<b>This is bold text</b>", _
                    "<H1>This is large Text</H1>", _
                    "<b><i><font color = green>This has multiple tags</font></i></b>", _
                    "<b>This has <i>embedded</i> tags.</b>", _
                    "<This line simply begins with a lesser than symbol, it should not be modified"}

        ' process a string that contains html tags
        ' this sample does not remove embedded tags (tags in the middle of a line)

        Console.WriteLine("The following lists the items before the tags have been stripped:")
        Console.WriteLine("-----------------------------------------------------------------")

        ' print out the initial array of strings
        Dim s As String
        For Each s In  strSource
            Console.WriteLine(s)
        Next s

        Console.WriteLine()

        Console.WriteLine("The following lists the items after the tags have been stripped:")
        Console.WriteLine("----------------------------------------------------------------")

        ' print out the array of strings
        For Each s In  strSource
            Console.WriteLine(StripStartTags(s))
        Next s

    End Sub 'Main

    Private Shared Function StripStartTags(item As String) As String

        ' try to find a tag at the start of the line using StartsWith
        If item.Trim().StartsWith("<") Then

            ' now search for the closing tag...
           Dim lastLocation As Integer = item.IndexOf(">")

            If lastLocation >= 0 Then
                ' remove the identified section, if it is a valid region
                item = item.Substring((lastLocation + 1))
            End If
        End If

        Return item

    End Function 'StripStartTags

End Class 'EndsWithTest


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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