How to: Read Characters from a String
The following code example allows you to read a certain number of characters from an existing string, starting at a specified place in the string. Use StringReader to do this, as demonstrated below.
This code defines a string and converts it to an array of characters, which can then be read by using the appropriate StringReader.Read method.
This example reads only the specified number of characters from the string, as follows.
Example
Imports System
Imports System.IO
Public Class CharsFromStr
Public Shared Sub Main()
' Create a string to read characters from.
Dim str As String = "Some number of characters"
' Make a char array the size of the source string
Dim b(str.Length) As Char
' Create an instance of StringReader and attach it to the string.
Dim sr As New StringReader(str)
' Read 13 characters into the array that holds the string,
' starting at the third array member.
sr.Read(b, 0, 13)
' Display the output.
Console.WriteLine(b)
' Read the rest of the string from the current position in the
' source string into the array, starting at the 6th array member.
sr.Read(b, 5, str.Length - 13)
' Display the output.
Console.WriteLine(b)
' Close the StringReader.
sr.Close()
End Sub
End Class
' The example has the following output:
'
' Some number o
' Some f characters
using System;
using System.IO;
public class CharsFromStr
{
public static void Main()
{
// Create a string to read characters from.
string str = "Some number of characters";
// Make a char array the size of the source string
char[] b = new char[str.Length];
// Create an instance of StringReader and attach it to the string.
StringReader sr = new StringReader(str);
// Read 13 characters into the array that holds the string,
// starting at the third array member.
sr.Read(b, 0, 13);
// Display the output.
Console.WriteLine(b);
// Read the rest of the string from the current position in the
// source string into the array, starting at the 6th array member.
sr.Read(b, 5, str.Length - 13);
// Display the output.
Console.WriteLine(b);
// Close the StringReader.
sr.Close();
}
}
// The example has the following output:
//
// Some number o
// Some f characters
using namespace System;
using namespace System::IO;
public ref class CharsFromStr
{
public:
static void Main()
{
// Create a string to read characters from.
String^ str = "Some number of characters";
// Make a char array the size of the source string
array<Char>^ b = gcnew array<Char>(str->Length);
// Create an instance of StringReader and attach it to the string.
StringReader^ sr = gcnew StringReader(str);
// Read 13 characters into the array that holds the string,
// starting at the third array member.
sr->Read(b, 0, 13);
// Display the output.
Console::WriteLine(b);
// Read the rest of the string from the current position in the
// source string into the array, starting at the 6th array member.
sr->Read(b, 5, str->Length - 13);
// Display the output.
Console::WriteLine(b);
// Close the StringReader.
sr->Close();
}
};
int main()
{
CharsFromStr::Main();
}
// The example has the following output:
//
// Some number o
// Some f characters
See Also
Tasks
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How to: Read and Write to a Newly Created Data File
How to: Open and Append to a Log File
How to: Write Characters to a String