IndentedTextWriter Class

Provides a text writer that can indent new lines by a tab string token.

Namespace: System.CodeDom.Compiler
Assembly: System (in system.dll)

'Declaration
Public Class IndentedTextWriter
	Inherits TextWriter
'Usage
Dim instance As IndentedTextWriter

public class IndentedTextWriter extends TextWriter
public class IndentedTextWriter extends TextWriter
Not applicable.

IndentedTextWriter extends a TextWriter by providing methods that insert a tab string and track the current indentation level. Text formatted with multiple indentation levels is useful for generated code, so this class is used by CodeDOM code generator implementations.

The tab string is the string that each indentation consists of. Typically the tab string contains white space.

NoteNote:

This class contains a link demand and an inheritance demand at the class level that applies to all members. A SecurityException is thrown when either the immediate caller or the derived class does not have full-trust permission. For details about security demands, see Link Demands and Inheritance Demands.

The following code example demonstrates using an IndentedTextWriter to write text at different levels of indentation.

Imports System
Imports System.CodeDom
Imports System.CodeDom.Compiler
Imports System.ComponentModel
Imports System.IO
Imports System.Windows.Forms

Public Class Form1
   Inherits System.Windows.Forms.Form
   Private textBox1 As System.Windows.Forms.TextBox 
   
   Private Function CreateMultilevelIndentString() As String
        ' Create a TextWriter to use as the base output writer.
        Dim baseTextWriter As New System.IO.StringWriter
      
        ' Create an IndentedTextWriter and set the tab string to use 
        ' as the indentation string for each indentation level.
        Dim indentWriter = New IndentedTextWriter(baseTextWriter, "    ")

        ' Set the indentation level.
        indentWriter.Indent = 0

        ' Output test strings at stepped indentations through a recursive loop method.
        WriteLevel(indentWriter, 0, 5)
      
        ' Return the resulting string from the base StringWriter.
        Return baseTextWriter.ToString()
    End Function

    Private Sub WriteLevel(ByVal indentWriter As IndentedTextWriter, ByVal level As Integer, ByVal totalLevels As Integer)
        ' Outputs a test string with a new-line character at the end.
        indentWriter.WriteLine(("This is a test phrase. Current indentation level: " + level.ToString()))

        ' If not yet at the highest recursion level, call this output method for the next level of indentation.
        If level < totalLevels Then
            ' Increase the indentation count for the next level of indented output.
            indentWriter.Indent += 1

            ' Call the WriteLevel method to write test output for the next level of indentation.
            WriteLevel(indentWriter, level + 1, totalLevels)

            ' Restores the indentation count for this level after the recursive branch method has returned.
            indentWriter.Indent -= 1

        Else
            ' Output a string using the WriteLineNoTabs method.
            indentWriter.WriteLineNoTabs("This is a test phrase written with the IndentTextWriter.WriteLineNoTabs method.")
        End If

        ' Outputs a test string with a new-line character at the end.
        indentWriter.WriteLine(("This is a test phrase. Current indentation level: " + level.ToString()))
    End Sub

    Private Sub button1_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        textBox1.Text = CreateMultilevelIndentString()
    End Sub

    Public Sub New()
        Dim button1 As New System.Windows.Forms.Button
        Me.textBox1 = New System.Windows.Forms.TextBox
        Me.SuspendLayout()
        Me.textBox1.Anchor = CType(System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Left Or System.Windows.Forms.AnchorStyles.Right, System.Windows.Forms.AnchorStyles)
        Me.textBox1.Location = New System.Drawing.Point(8, 40)
        Me.textBox1.Multiline = True
        Me.textBox1.Name = "textBox1"
        Me.textBox1.Size = New System.Drawing.Size(391, 242)
        Me.textBox1.TabIndex = 0
        Me.textBox1.Text = ""
        button1.Location = New System.Drawing.Point(11, 8)
        button1.Name = "button1"
        button1.Size = New System.Drawing.Size(229, 23)
        button1.TabIndex = 1
        button1.Text = "Generate string using IndentedTextWriter"
        AddHandler button1.Click, AddressOf Me.button1_Click
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(407, 287)
        Me.Controls.Add(button1)
        Me.Controls.Add(Me.textBox1)
        Me.Name = "Form1"
        Me.Text = "IndentedTextWriter example"
        Me.ResumeLayout(False)
    End Sub

    <STAThread()> _
    Shared Sub Main()
        Application.Run(New Form1)
    End Sub
End Class

package IndentedTextWriterExample; 

import System.*;
import System.CodeDom.*;
import System.CodeDom.Compiler.*;
import System.ComponentModel.*;
import System.IO.*;
import System.Windows.Forms.*;

public class Form1 extends System.Windows.Forms.Form
{
    private System.Windows.Forms.TextBox textBox1;

    private String CreateMultilevelIndentString()
    {
        // Creates a TextWriter to use as the base output writer.
        System.IO.StringWriter baseTextWriter = new System.IO.StringWriter();

        // Create an IndentedTextWriter and set the tab string to use 
        // as the indentation string for each indentation level.
        System.CodeDom.Compiler.IndentedTextWriter indentWriter 
            = new IndentedTextWriter(baseTextWriter, "    ");

        // Sets the indentation level.
        indentWriter.set_Indent(0);

        // Output test strings at stepped indentations through a 
        //recursive loop method.
        WriteLevel(indentWriter, 0, 5);

        // Return the resulting string from the base StringWriter.
        return baseTextWriter.ToString();
    } //CreateMultilevelIndentString

    private void WriteLevel(IndentedTextWriter indentWriter, int level,
        int totalLevels)
    {
        // Output a test string with a new-line character at the end.
        indentWriter.WriteLine("This is a test phrase."
            +" Current indentation level: " 
            + System.Convert.ToString(level));

        // If not yet at the highest recursion level, call this output method
        // for the next level of indentation.
        if (level < totalLevels) {
            // Increase the indentation count for the next level of
            // indented output.
            indentWriter.set_Indent(indentWriter.get_Indent() + 1);

            // Call the WriteLevel method to write test output for the
            // next level of indentation.
            WriteLevel(indentWriter, level + 1, totalLevels);

            // Restores the indentation count for this level after the
            // recursive branch method has returned.
            indentWriter.set_Indent(indentWriter.get_Indent() - 1);
        }
        // Outputs a string using the WriteLineNoTabs method.
        else {
            indentWriter.WriteLineNoTabs("This is a test phrase written with"
                +" the IndentTextWriter.WriteLineNoTabs method.");
        } 
        // Outputs a test string with a new-line character at the end.
        indentWriter.WriteLine("This is a test phrase."
            +" Current indentation level: " 
            + System.Convert.ToString(level));
    } //WriteLevel

    private void button1_Click(Object sender, System.EventArgs e)
    {
        textBox1.set_Text(CreateMultilevelIndentString());
    } //button1_Click

    public Form1()
    {
        System.Windows.Forms.Button button1 = new System.Windows.Forms.Button();
        this.textBox1 = new System.Windows.Forms.TextBox();
        this.SuspendLayout();
        this.textBox1.set_Anchor(((System.Windows.Forms.AnchorStyles)(
            System.Windows.Forms.AnchorStyles.Top 
            | System.Windows.Forms.AnchorStyles.Bottom 
            | System.Windows.Forms.AnchorStyles.Left 
            | System.Windows.Forms.AnchorStyles.Right)));
        this.textBox1.set_Location(new System.Drawing.Point(8, 40));
        this.textBox1.set_Multiline(true);
        this.textBox1.set_Name("textBox1");
        this.textBox1.set_Size(new System.Drawing.Size(391, 242));
        this.textBox1.set_TabIndex(0);
        this.textBox1.set_Text("");
        button1.set_Location(new System.Drawing.Point(11, 8));
        button1.set_Name("button1");
        button1.set_Size(new System.Drawing.Size(229, 23));
        button1.set_TabIndex(1);
        button1.set_Text("Generate string using IndentedTextWriter");
        button1.add_Click(new System.EventHandler(this.button1_Click));
        this.set_AutoScaleBaseSize(new System.Drawing.Size(5, 13));
        this.set_ClientSize(new System.Drawing.Size(407, 287));
        this.get_Controls().Add(button1);
        this.get_Controls().Add(this.textBox1);
        this.set_Name("Form1");
        this.set_Text("IndentedTextWriter example");
        this.ResumeLayout(false);
    } //Form1

    /** @attribute STAThread()
     */
    public static void main(String[] args)
    {
        Application.Run(new Form1());
    } //main
} //Form1

  • SecurityAction.LinkDemand  for full trust for the immediate caller. This class cannot be used by partially trusted code.
  • SecurityAction.InheritanceDemand  for full trust for inheritors. This class cannot be inherited by partially trusted code.

System.Object
   System.MarshalByRefObject
     System.IO.TextWriter
      System.CodeDom.Compiler.IndentedTextWriter

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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