[RESOLVED] How to read arrays from Binary Files?

[usycool1]

Hey everyone,
How can I read arrays from Binary Files?

Don't worry, I've got the answers now

[i00]

I would suggest storing the recipes in a a list(of FullRecipe) and then serializing the list(of FullRecipe) object... easy way to store and retrieve what you want ... follow the "File serialization with compression and encryption" link in my signature

Kris

[minitech]

Use a System.IO.BinaryWriter and System.IO.BinaryReader, they're quite convenient. Just call Write() on the BinaryWriter for each field, for each recipe. With the ArrayLists (which should be List(Of t)s, I suggest you change that as soon as possible) you would just write out the length, then each item. When reading it back, you would do something like:

Dim r As FullRecipe
r.Name = reader.ReadString()
r.Units = New List(Of String)
For i As Integer = 1 To reader.ReadInt32()
    r.Units.Add(reader.ReadString())
Next
r.Ingredients = New List(Of String)
For i As Integer = 1 To reader.ReadInt32()
    r.Ingredients.Add(reader.ReadString())
Next
r.Quantity = New List(Of String)
For i As Integer = 1 To reader.ReadInt32()
    r.Quantity.Add(reader.ReadString())
Next
r.NumberOfPeople = reader.ReadInt32()

'Done reading!

You already have the right idea with LengthOfQuantityList, but it's not necessary - you can easily do Quantity.Length or Quantity.Count.

[usycool1]

Thanks a lot, guys I will give them both a go

[usycool1]

Use a System.IO.BinaryWriter and System.IO.BinaryReader, they're quite convenient. Just call Write() on the BinaryWriter for each field, for each recipe. With the ArrayLists (which should be List(Of t)s, I suggest you change that as soon as possible) you would just write out the length, then each item. When reading it back, you would do something like:

Dim r As FullRecipe
r.Name = reader.ReadString()
r.Units = New List(Of String)
For i As Integer = 1 To reader.ReadInt32()
    r.Units.Add(reader.ReadString())
Next
r.Ingredients = New List(Of String)
For i As Integer = 1 To reader.ReadInt32()
    r.Ingredients.Add(reader.ReadString())
Next
r.Quantity = New List(Of String)
For i As Integer = 1 To reader.ReadInt32()
    r.Quantity.Add(reader.ReadString())
Next
r.NumberOfPeople = reader.ReadInt32()

'Done reading!

You already have the right idea with LengthOfQuantityList, but it's not necessary - you can easily do Quantity.Length or Quantity.Count.

Hi, whenever I try to use your example, this happens (Please see attachment).

Do you know what I'm doing wrong?

[minitech]

Can you post your writing code? You might not have mirrored the reading scheme quite right. Sorry for not posting that part.

[usycool1]

Can you post your writing code? You might not have mirrored the reading scheme quite right. Sorry for not posting that part.

Yeah, sure here it is:

'Make a procedure which stores the values into a Binary File.
    Sub WriteToFile(ByVal WriteRecipe As Recipe, ByVal FileWriter As BinaryWriter)
        'Write everything to the Binary File.
        FileWriter.Write(WriteRecipe.Name)
        FileWriter.Write(WriteRecipe.NumberToServe)

        For Each x In WriteRecipe.Ingredients
            FileWriter.Write(x)
        Next

        For Each y In WriteRecipe.Units
            FileWriter.Write(y)
        Next

        For Each z In WriteRecipe.Quantities
            FileWriter.Write(z)
        Next
    End Sub

Thanks a lot for your help, by the way, I really appreciate it

[minitech]

No problem

The problem is you didn't write the number of items before writing the items. Easy fix, though:

    'Make a procedure which stores the values into a Binary File.
    Sub WriteToFile(ByVal WriteRecipe As Recipe, ByVal FileWriter As BinaryWriter)
        'Write everything to the Binary File.
        FileWriter.Write(WriteRecipe.Name)
        FileWriter.Write(WriteRecipe.NumberToServe)

        FileWriter.Write(WriteRecipe.Ingredients.Count)
        For Each x In WriteRecipe.Ingredients
            FileWriter.Write(x)
        Next

        FileWriter.Write(WriteRecipe.Units.Count)
        For Each y In WriteRecipe.Units
            FileWriter.Write(y)
        Next

        FileWriter.Write(WriteRecipe.Quantities.Count)
        For Each z In WriteRecipe.Quantities
            FileWriter.Write(z)
        Next
    End Sub

[usycool1]

No problem

The problem is you didn't write the number of items before writing the items. Easy fix, though:

    'Make a procedure which stores the values into a Binary File.
    Sub WriteToFile(ByVal WriteRecipe As Recipe, ByVal FileWriter As BinaryWriter)
        'Write everything to the Binary File.
        FileWriter.Write(WriteRecipe.Name)
        FileWriter.Write(WriteRecipe.NumberToServe)

        FileWriter.Write(WriteRecipe.Ingredients.Count)
        For Each x In WriteRecipe.Ingredients
            FileWriter.Write(x)
        Next

        FileWriter.Write(WriteRecipe.Units.Count)
        For Each y In WriteRecipe.Units
            FileWriter.Write(y)
        Next

        FileWriter.Write(WriteRecipe.Quantities.Count)
        For Each z In WriteRecipe.Quantities
            FileWriter.Write(z)
        Next
    End Sub

Thanks a lot! It's working now

[minitech]

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