Question : writing a fixed length text file

I currently have a routine which creates a delimited text file but I have to have a fixed length text file.

How can I change the following code to accomplish this?

(vb.net with a sqlce database)



        Dim sw As StreamWriter = New StreamWriter("Transactions.txt")
        Try
            cn.Open()
            cnCmd.CommandText = "Select description, document, part_num, cur_qty, cond_code, generic1, generic2  from tblinventory"
            cnCmd.Connection = cn
            drDB = cnCmd.ExecuteReader

            While drDB.Read
                sw.WriteLine(drDB.Item("description") & drDB.Item("document") & "LINE" & "," & drDB.Item("part_num") & "," & "RIC" & "," & "UI" & "," & drDB.Item("cur_qty") & "," & drDB.Item("cond_code") & "," & drDB.Item("document") & "," & drDB.Item("generic1") & "," & drDB.Item("generic2"))
            End While
            drDB.Close()

            cn.Close()


Thanks for any assistance

Answer : writing a fixed length text file

I think both posts above are a little simplistic in their approach.  Most fixed width text files do not simply have a fixed width for the entire line...instead, each column of data usually has a specific width so you need to pad each individual piece of data coming out of your database.

In your example you have these pieces of data:

    description, document, part_num, cur_qty, cond_code, generic1, generic2

I'm guessing that description, document cond_code, generic1 and generic2 are just normal alphanumeric strings that need to be left aligned and padded on the right with spaces.  But part_num and cur_qty look like they might contain actual numbers.  Often in fixed width files we right align numbers and pad the left with zeroes.

So in the code below, I first extract all the values from the database into individual variables.  Then I build the "line" variable by adding all the pieces with the appropriate padding.  You will need to adjust these numbers to fit your requirements.  I made description have a width of 30, while the document field had a width of 25, etc...

Notice that in the part_num and cur_qty fields, the format is different.  I used PadLeft() instead of PadRight() and specified a "0" as the fill character.  So if the cur_qty was 123, it would appear as "00123" because I specifed a length of 5 with "0" as the padding character.

Hope it helps...

        Dim sw As StreamWriter = New StreamWriter("Transactions.txt")
        Dim line As String

        Try
            cn.Open()
            cnCmd.CommandText = "Select description, document, part_num, cur_qty, cond_code, generic1, generic2  from tblinventory"
            cnCmd.Connection = cn
            drDB = cnCmd.ExecuteReader

            Dim description As String, document As String
            Dim part_num As String, cur_qty As String
            Dim cond_code As String, generic1 As String
            Dim generic2 As String

            While drDB.Read
                description = drDB.Item("description")
                document = drDB.Item("document")
                part_num = drDB.Item("part_num")
                cur_qty = drDB.Item("cur_qty")
                cond_code = drDB.Item("cond_code")
                generic1 = drDB.Item("generic1")
                generic2 = drDB.Item("generic2")

                line = description.PadRight(30) & document.PadRight(25) & "LINE," _
                    & part_num.PadLeft(10, "0") & ",RIC,UI," & cur_qty.padleft(5, "0") _
                    & "," & cond_code.PadRight(3) & "," & document.PadRight(25) _
                    & "," & generic1.PadRight(20) & "," & generic2.PadRight(20)

                sw.WriteLine(line) ' change padding parameter accordingly!
            End While
            drDB.Close()

            cn.Close()