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How to: Write 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.

Example

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 = {" ","t","o"," ","w","r","i","t","e"," ","t","o","."}
        ' 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
using System;
using System.IO;
using System.Text;

public class CharsToStr
{
    public static void Main()
    {
        // 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();
    }
}
using namespace System;
using namespace System::IO;
using namespace System::Text;

public ref class CharsToStr
{
public:
    static void Main()
    {
        // Create an instance of StringBuilder that can then be modified.
        StringBuilder^ sb = gcnew StringBuilder("Some number of characters");
        // Define and create an instance of a character array from which
        // characters will be read into the StringBuilder.
        array<Char>^ b = {' ','t','o',' ','w','r','i','t','e',' ','t','o','.'};
        // Create an instance of StringWriter
        // and attach it to the StringBuilder.
        StringWriter^ sw = gcnew 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();
    }
};

int main()
{
    CharsToStr::Main();
}

Robust Programming

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

Tasks

How to: Create a Directory Listing

How to: Read and Write to a Newly Created Data File

How to: Open and Append to a Log File

How to: Read Text from a File

How to: Write Text to a File

How to: Read Characters from a String

Reference

StringWriter

StringWriter.Write

StringBuilder

Concepts

Basic File I/O