CompareInfo::IsPrefix Method (String^, String^, CompareOptions)
Determines whether the specified source string starts with the specified prefix using the specified CompareOptions value.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- source
-
Type:
System::String^
The string to search in.
- prefix
-
Type:
System::String^
The string to compare with the beginning of source.
- options
-
Type:
System.Globalization::CompareOptions
A value that defines how source and prefix should be compared. options is either the enumeration value Ordinal, or a bitwise combination of one or more of the following values: IgnoreCase, IgnoreSymbols, IgnoreNonSpace, IgnoreWidth, and IgnoreKanaType.
Return Value
Type: System::Booleantrue if the length of prefix is less than or equal to the length of source and source starts with prefix; otherwise, false.
| Exception | Condition |
|---|---|
| ArgumentNullException | source is null. -or- prefix is null. |
| ArgumentException | options contains an invalid CompareOptions value. |
Every string starts and ends with an empty substring (""); therefore, if prefix is an empty string, this method returns true.
The CompareOptions::StringSort value is not valid for this method.
Note |
|---|
When possible, you should call string comparison methods that have a parameter of type CompareOptions to specify the kind of comparison expected. As a general rule, use linguistic options (using the current culture) for comparing strings displayed in the user interface and specify CompareOptions::Ordinal or CompareOptions::OrdinalIgnoreCase for security comparisons. |
The following example determines whether a string is the prefix or suffix of another string using CompareOptions.
using namespace System; using namespace System::Globalization; int main() { // Defines the strings to compare. String^ myStr1 = "calle"; String^ myStr2 = "llegar"; String^ myXfix = "LLE"; // Uses the CompareInfo property of the InvariantCulture. CompareInfo^ myComp = CultureInfo::InvariantCulture->CompareInfo; Console::WriteLine( "IsSuffix \"{0}\", \"{1}\"", myStr1, myXfix ); Console::WriteLine( " With no CompareOptions : {0}", myComp->IsSuffix( myStr1, myXfix ) ); Console::WriteLine( " With None : {0}", myComp->IsSuffix( myStr1, myXfix, CompareOptions::None ) ); Console::WriteLine( " With Ordinal : {0}", myComp->IsSuffix( myStr1, myXfix, CompareOptions::Ordinal ) ); Console::WriteLine( " With IgnoreCase : {0}", myComp->IsSuffix( myStr1, myXfix, CompareOptions::IgnoreCase ) ); Console::WriteLine( "IsPrefix \"{0}\", \"{1}\"", myStr2, myXfix ); Console::WriteLine( " With no CompareOptions : {0}", myComp->IsPrefix( myStr2, myXfix ) ); Console::WriteLine( " With None : {0}", myComp->IsPrefix( myStr2, myXfix, CompareOptions::None ) ); Console::WriteLine( " With Ordinal : {0}", myComp->IsPrefix( myStr2, myXfix, CompareOptions::Ordinal ) ); Console::WriteLine( " With IgnoreCase : {0}", myComp->IsPrefix( myStr2, myXfix, CompareOptions::IgnoreCase ) ); } /* This code produces the following output. IsSuffix "calle", "LLE" With no CompareOptions : False With None : False With Ordinal : False With IgnoreCase : True IsPrefix "llegar", "LLE" With no CompareOptions : False With None : False With Ordinal : False With IgnoreCase : True */
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
