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Write Object Array to Binary File

I have created a multidimensional object array (Holds a heap). The following are the data types for each node:
All the data in column 0 = string
All the data in column 1 = long int
All the data in column 2 = string
All the data in column 3 = float
All the data in column 4 = int

I want to now place this whole array into a binary text file. Below is the code that i have produced to write the data to the binary file. When i run the program i receive an error saying it can't convert from object to bool. What am i doing wrong? Is there a better way to do this?

static void SaveHeap()// called by Main
        {
            BinaryWriter HeapInput = new BinaryWriter(new FileStream("HeapFile.txt", FileMode.OpenOrCreate));
 
            HeapInput.Write(N);
 
            for (int i = 1; i <= N; i++)
            {
                for (int j = 1; j <= 4; j++)
                {
                    HeapInput.Write(HeapHold[i, j]);
                }
            }
 
            HeapInput.Flush();
            HeapInput.Close();
 
            WriteToLog.WriteLine("*SaveHeap done - Heap has {0} nodes", N.ToString("d2"));
            WriteToLog.WriteLine();
        }

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JimBrandley

BinaryWriter.Write() does not have an overload that takes an object. So, try this:

for (int i = 1; i <= N; i++)
{
HeapInput.Write((string)HeapHold[i, 0]);
HeapInput.Write((long)HeapHold[i, 1]);
HeapInput.Write((string)HeapHold[i, 2]);
HeapInput.Write((float)HeapHold[i, 3]);
HeapInput.Write((int)HeapHold[i, 4]);
}

Also, did you intend to skip the first entry in the array? It is:
for (int i = 1; i <= N; i++)

but I would expect:
for (int i = 0; i < N; i++)

Jim

ericwong27

Maybe the Serializes Technique is a better solution

using System;
using System.IO;
using System.Collections;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization;
 
public class App 
{
    [STAThread]
    static void Main() 
    {
        Serialize();
        Deserialize();
    }
 
    static void Serialize() 
    {
        // Create a hashtable of values that will eventually be serialized.
        Hashtable addresses = new Hashtable();
        addresses.Add("Jeff", "123 Main Street, Redmond, WA 98052");
        addresses.Add("Fred", "987 Pine Road, Phila., PA 19116");
        addresses.Add("Mary", "PO Box 112233, Palo Alto, CA 94301");
 
        // To serialize the hashtable and its key/value pairs,  
        // you must first open a stream for writing. 
        // In this case, use a file stream.
        FileStream fs = new FileStream("DataFile.dat", FileMode.Create);
 
        // Construct a BinaryFormatter and use it to serialize the data to the stream.
        BinaryFormatter formatter = new BinaryFormatter();
        try 
        {
            formatter.Serialize(fs, addresses);
        }
        catch (SerializationException e) 
        {
            Console.WriteLine("Failed to serialize. Reason: " + e.Message);
            throw;
        }
        finally 
        {
            fs.Close();
        }
    }
 
   
    static void Deserialize() 
    {
        // Declare the hashtable reference.
        Hashtable addresses  = null;
 
        // Open the file containing the data that you want to deserialize.
        FileStream fs = new FileStream("DataFile.dat", FileMode.Open);
        try 
        {
            BinaryFormatter formatter = new BinaryFormatter();
 
            // Deserialize the hashtable from the file and 
            // assign the reference to the local variable.
            addresses = (Hashtable) formatter.Deserialize(fs);
        }
        catch (SerializationException e) 
        {
            Console.WriteLine("Failed to deserialize. Reason: " + e.Message);
            throw;
        }
        finally 
        {
            fs.Close();
        }
 
        // To prove that the table deserialized correctly, 
        // display the key/value pairs.
        foreach (DictionaryEntry de in addresses) 
        {
            Console.WriteLine("{0} lives at {1}.", de.Key, de.Value);
        }
    }
}

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jmkotman

ASKER

Jim,
Your solution seemed to work wonderfully. I am now going to write another method to read in those files. Below is the code i have written. Is there a better way to read in that binary file? Can i read it in the same way i output it?

static void Main(string[] args)
        {
            int N = 0;
            string titleCode = "";
            long isbn;
            string title = "";
            float price;
            int localID = 0;
 
            BinaryReader HeapInput = new BinaryReader(new FileStream("C:\\Users\\Ryan\\Documents\\Visual Studio 2005\\Projects\\Assignment_2\\Assignment_2\\bin\\Debug\\HeapFile.txt", FileMode.Open));
 
            if(N == 0)
            {
                N = HeapInput.ReadInt32();
            }
 
            WriteToLog.WriteLine("*Dump of the HeapFile: N = {0}", N.ToString("d2"));
 
            for (int i = 1; i <= N ; i++)
            {
                titleCode = (string)HeapInput.Read();
                isbn = (long)HeapInput.Read();
                title = (string)HeapInput.Read();
                price = (float)HeapInput.Read();
                localID = (int)HeapInput.Read();
 
                WriteToLog.WriteLine("{0} // {1} {2} {3} {4} {5}");
            }
 
            WriteToLog.WriteLine();
            WriteToLog.WriteLine();
        }

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JimBrandley

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