BinaryReader.ReadBoolean Method   
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Reads a Boolean value from the current stream and advances the current position of the stream by one byte.
public:
 virtual bool ReadBoolean();public virtual bool ReadBoolean();abstract member ReadBoolean : unit -> bool
override this.ReadBoolean : unit -> boolPublic Overridable Function ReadBoolean () As BooleanReturns
true if the byte is nonzero; otherwise, false.
Exceptions
The end of the stream is reached.
The stream is closed.
An I/O error occurred.
Examples
The following code example demonstrates how to store and retrieve application settings in a file.
using System;
using System.IO;
using System.Text;
class ConsoleApplication
{
    const string fileName = "AppSettings.dat";
    static void Main()
    {
        WriteDefaultValues();
        DisplayValues();
    }
    public static void WriteDefaultValues()
    {
        using (var stream = File.Open(fileName, FileMode.Create))
        {
            using (var writer = new BinaryWriter(stream, Encoding.UTF8, false))
            {
                writer.Write(1.250F);
                writer.Write(@"c:\Temp");
                writer.Write(10);
                writer.Write(true);
            }
        }
    }
    public static void DisplayValues()
    {
        float aspectRatio;
        string tempDirectory;
        int autoSaveTime;
        bool showStatusBar;
        if (File.Exists(fileName))
        {
            using (var stream = File.Open(fileName, FileMode.Open))
            {
                using (var reader = new BinaryReader(stream, Encoding.UTF8, false))
                {
                    aspectRatio = reader.ReadSingle();
                    tempDirectory = reader.ReadString();
                    autoSaveTime = reader.ReadInt32();
                    showStatusBar = reader.ReadBoolean();
                }
            }
            Console.WriteLine("Aspect ratio set to: " + aspectRatio);
            Console.WriteLine("Temp directory is: " + tempDirectory);
            Console.WriteLine("Auto save time set to: " + autoSaveTime);
            Console.WriteLine("Show status bar: " + showStatusBar);
        }
    }
}
open System.IO
open System.Text
let fileName = "AppSettings.dat"
let writeDefaultValues () =
    use stream = File.Open(fileName, FileMode.Create)
    use writer = new BinaryWriter(stream, Encoding.UTF8, false)
    writer.Write 1.250F
    writer.Write @"c:\Temp"
    writer.Write 10
    writer.Write true
let displayValues () =
    if File.Exists fileName then
        use stream = File.Open(fileName, FileMode.Open)
        use reader = new BinaryReader(stream, Encoding.UTF8, false)
        let aspectRatio = reader.ReadSingle()
        let tempDirectory = reader.ReadString()
        let autoSaveTime = reader.ReadInt32()
        let showStatusBar = reader.ReadBoolean()
        printfn $"Aspect ratio set to: {aspectRatio}"
        printfn $"Temp directory is: {tempDirectory}"
        printfn $"Auto save time set to: {autoSaveTime}"
        printfn $"Show status bar: {showStatusBar}"
writeDefaultValues ()
displayValues ()
Imports System.IO
Module Module1
    Const fileName As String = "AppSettings.dat"
    Sub Main()
        WriteDefaultValues()
        DisplayValues()
    End Sub
    Sub WriteDefaultValues()
        Using writer As BinaryWriter = New BinaryWriter(File.Open(fileName, FileMode.Create))
            writer.Write(1.25F)
            writer.Write("c:\Temp")
            writer.Write(10)
            writer.Write(True)
        End Using
    End Sub
    Sub DisplayValues()
        Dim aspectRatio As Single
        Dim tempDirectory As String
        Dim autoSaveTime As Integer
        Dim showStatusBar As Boolean
        If (File.Exists(fileName)) Then
            Using reader As BinaryReader = New BinaryReader(File.Open(fileName, FileMode.Open))
                aspectRatio = reader.ReadSingle()
                tempDirectory = reader.ReadString()
                autoSaveTime = reader.ReadInt32()
                showStatusBar = reader.ReadBoolean()
            End Using
            Console.WriteLine("Aspect ratio set to: " & aspectRatio)
            Console.WriteLine("Temp directory is: " & tempDirectory)
            Console.WriteLine("Auto save time set to: " & autoSaveTime)
            Console.WriteLine("Show status bar: " & showStatusBar)
        End If
    End Sub
End Module
Remarks
BinaryReader does not restore the file position after an unsuccessful read.
For a list of common I/O tasks, see Common I/O Tasks.