[RESOLVED] Problem writing to a file using Fixed Array

[gil4x4]

Hi Everybody,

I am trying to write a program that will use a Structure with <VBFixedString(4), VBFixedArray(10)> Public Test1() As String.
Back in vb6 it was in the Type statement as Test1(10) as string *4
When I hit the line ".Test1(X) = TB1" i get the following error:
Object reference not set to an instance of an object.

Below is the code, any help is greatly appriciated.

Option Strict Off
Option Explicit On
Public Class Form1
    Inherits System.Windows.Forms.Form

    Structure FileFormat
        <VBFixedString(8)> Public Username As String
        <VBFixedString(4), VBFixedArray(10)> Public Test1() As String
        <VBFixedString(4), VBFixedArray(10)> Public Test2() As String
        <VBFixedString(4), VBFixedArray(10)> Public Test3() As String
        <VBFixedString(4), VBFixedArray(10)> Public Test4() As String
        <VBFixedString(4), VBFixedArray(10)> Public Test5() As String
    End Structure

	Dim AllFileFormat As FileFormat
	Dim Username As String
	Dim TB1 As String
	Dim TB2 As String
	Dim TB3 As String
	Dim TB4 As String
	Dim TB5 As String
             Dim FN As String
	Dim FBuf As Short
	Dim FLen As Integer
	Dim Rec As Integer
             Dim Num As Short
             Dim X As Integer
	
	Private Sub Command1_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles Command1.Click
        Rec = 1
		Num = 1
        Username = "TEST"
		TB1 = UCase(Trim(T1.Text))
		TB2 = UCase(Trim(T2.Text))
		TB3 = UCase(Trim(T3.Text))
		TB4 = UCase(Trim(T4.Text))
		TB5 = UCase(Trim(T5.Text))
		
        FN = "D:\TestFixedArray.txt"
		FBuf = FreeFile
		FLen = Len(AllFileFormat)
		
        FileOpen(FBuf, FN, OpenMode.Random, OpenAccess.Write, OpenShare.Shared, FLen)
        .Username = Username
        For X = 1 To 10
            With AllFileFormat
                .Test1(X) = TB1
                .Test2(X) = TB2
                .Test3(X) = TB3
                .Test4(X) = TB4
                .Test5(X) = TB5
            End With
        Next X
        FilePut(FBuf, AllFileFormat, 1)
        FileClose(FBuf)
    End Sub
End Class

[kleinma]

When you loop X = 1 to 10, you are trying to assign the same text value to each element of the array in your structure. So if TB1 equals "TEST" then every element of the Test1 array is going to be the same value of "TEST" so I am not sure if that is what you are looking to do, it doesn't make much sense to me.

The specific reason for your error is that your elements of your structure (test1, test2, etc.) you declared as arrays, so you need to redim them with an actual bounds before you can use them.

Like

ReDim AllFileFormat.Test1(9)

Keep in mind in .NET all arrays start at index 0, You can't make an array that has a range of 1 to 10 like you could in VB6.

[gil4x4]

That was just an example as I wanted to keep the exact code private. I will give the 0 to 10 and reDim a shot an see if that works.

[kleinma]

Just note if you redim your array with an upperbound of 10, it will contain 11 elements (since it starts at 0)

If you only want 10 elements in your array redim it with a bounds of 9 so it will be 0 - 9 (10 elements)

[gil4x4]

Alright, I did the ReDim AllFileFormat.Test1(10) and wnt For X = 0 to 10 and it worked.

Thanks for all the help kleinma.

[kleinma]

No problem. Please mark the thread resolved using the thread tools menu above, and welcome to VBForums.