Writing Characters to a String

The following code example writes a certain number of characters from a character array into an existing string, starting at a specified place in the array. Use StringWriter to do this, as demonstrated below.

Option Explicit On 
Option Strict On
Imports System
Imports System.IO
Imports System.Text
Public Class CharsToStr
    Public Shared Sub Main()
        ' Create an instance of StringBuilder that can then be modified.
        Dim sb As New StringBuilder("Some number of characters")
        ' Define and create an instance of a character array from which 
        ' characters will be read into the StringBuilder.
        Dim b As Char() = {" "c, "t"c, "o"c, " "c, "w"c, "r"c, "i"c, "t"c, "e"c, " "c, "t"c, "o"c, "."c}
        ' Create an instance of StringWriter 
        ' and attach it to the StringBuilder.
        Dim sw As New StringWriter(sb)
        ' Write three characters from the array into the StringBuilder.
        sw.Write(b, 0, 3)
        ' Display the output.
        Console.WriteLine(sb)
        ' Close the StringWriter.
        sw.Close()
    End Sub
End Class

[C#]
using System;
using System.IO;
using System.Text;

public class CharsToStr
{
    public static void Main(String[] args)
    {
        // Create an instance of StringBuilder that can then be modified.
        StringBuilder sb = new StringBuilder("Some number of characters");
        // Define and create an instance of a character array from which 
        // characters will be read into the StringBuilder.
        char[] b = {' ','t','o',' ','w','r','i','t','e',' ','t','o','.'};
        // Create an instance of StringWriter 
        // and attach it to the StringBuilder.
        StringWriter sw = new StringWriter(sb);
        // Write three characters from the array into the StringBuilder.
        sw.Write(b, 0, 3);
        // Display the output.
        Console.WriteLine(sb);
        // Close the StringWriter.
        sw.Close();
    }
}

This example illustrates the use of a StringBuilder to modify an existing string. Note that this requires an additional using declaration, since the StringBuilder class is a member of the System.Text namespace. Also, instead of defining a string and converting it to a character array, this is an example of creating a character array directly and initializing it.

This code produces the following output.

Some number of characters to

See Also

Creating a Directory Listing | Reading and Writing to a Newly Created Data File | Opening and Appending to a Log File | Reading Text from a File | Writing Text to a File | Reading Characters from a String | Basic File I/O | StringWriter | StringWriter.Write | StringBuilder