Best way to put a contents of a dataset into a tab delimited file?

[The_Grudge]

I have a program that queries multiple data sources, firing the results of each query into a single dataset.

That part is working okay - I'm just now sure how best to proceed.

I need to export this dataset to a fixed length, tab delimited file. Should I loop through the data set and write lines to a text file (in which case I could use a sample), or is there a better way ?

Thanks.

[detlion1643]

Converting to VB shouldn't be hard... Reason being it's taken straight from one of my current applications I'm looking at atm:

using System.IO.StreamWriter streamWriter = new System.IO.StreamWriter(PathToFile + "\\" FileName + ".txt"))
{
    for(int i = 0; i = dataSet.Tables[0].Rows.Count; i ++)
    {
        streamWriter.WriteLine(dataSet.Tables[0].Rows[i, columnIndex]); //this writes each [row, column] value to a new line of the above txt file
        streamWriter.Flush(); //continually dump the stream to the file
    }
}

[techgnome]

Fixed-length and tab delimited are somewhat mutually exclusive...

fields are going to line up differently based on the contents of the field in a tab delimited file... fixed length on the other hand... means that all fields start at a given point (usually) on a row


-tg

[dday9]

I have a function in my signature that converts delimited textfiles to datatables and vice-versa. It includes things like: does it have a header? what do you want the delimiter to be? etc. Just check it out, it's here.

[MattP]

Fixed-length and tab delimited are somewhat mutually exclusive...

Definitely.

Tab delimited is easy so I thought I'd mess around with fixed-length and getting it to generate a format string from an array of field lengths. Negative numbers a left aligned and positive are right.

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
 
        Dim dt = GetDataTable()
 
        Dim fieldLengths = {-3, 10, 10, 5}
 
        WriteFixedLengthFile("C:\Temp\FixedTest.txt", dt, fieldLengths)
 
    End Sub
 
    Private Function GetDataTable() As DataTable
        Dim dt As New DataTable
 
        With dt.Columns
            .Add("ID", GetType(Integer)).AutoIncrement = True
            .Add("Description", GetType(String))
            .Add("Foo", GetType(String))
            .Add("Bar", GetType(String))
        End With
 
        With dt.Rows
            .Add(Nothing, "abcdefg", "abcdefg", "abc")
            .Add(Nothing, "hijklmn", "hijklmn", "hij")
            .Add(Nothing, "opqrstu", "opqrstu", "opq")
            .Add(Nothing, "vwxyz12", "vwxyz12", "vwx")
        End With
 
        Return dt
    End Function
 
    Private Sub WriteFixedLengthFile(fileName As String, dt As DataTable, fieldLengths As Integer())
 
        Dim formatString = GetFormatString(fieldLengths)
 
        Using sw As New IO.StreamWriter(fileName)
            For Each row In dt.Rows.Cast(Of DataRow).ToArray()
                sw.WriteLine(String.Format(formatString, row.ItemArray))
            Next
        End Using
 
    End Sub
 
    Private Function GetFormatString(fieldLengths As Integer()) As String
        Dim counter = 0
        Dim formatString = ""
 
        For Each length In fieldLengths
            formatString &= String.Format("{{{0},{1}}}", counter, length)
            counter += 1
        Next
 
        Return formatString
    End Function