First Declare a form level Dataset

Public Class frmCSV
    Dim ds As New DataSet

Next connect to your data source and build your dataset. In this case I am going to build one on the fly with this

Private Sub BuildDS()
     Dim dt As New DataTable
     Dim dr As DataRow
     Dim idColumn As DataColumn = _
         New DataColumn("ID", Type.GetType("System.Int32"))
     Dim FNColumn As DataColumn = _
         New DataColumn("FirstName", Type.GetType("System.String"))
     Dim LNColumn As DataColumn = _
         New DataColumn("LastName", Type.GetType("System.String"))

     dt.Columns.Add(idColumn)
     dt.Columns.Add(FNColumn)
     dt.Columns.Add(LNColumn)

     dr = dt.NewRow()
     dr("ID") = 1
     dr("FirstName") = "Randy"
     dr("LastName") = "Flag"
     dt.Rows.Add(dr)

     dr = dt.NewRow()
     dr("ID") = 2
     dr("FirstName") = "Tom"
     dr("LastName") = "Servo"
     dt.Rows.Add(dr)

     ds.Tables.Add(dt)

 End Sub

Now the code to loop trough your dataset and write the results to a file.

Private Sub WriteDS2CSV(ByVal ds As DataSet, ByVal FilePath As String)
    Dim str As New System.Text.StringBuilder
    For Each dr As DataRow In ds.Tables(0).Rows
        For Each field As Object In dr.ItemArray
            str.Append(field.ToString & ",")
        Next
        str.Replace(",", vbNewLine, str.Length - 1, 1)
    Next
    Try
        My.Computer.FileSystem.WriteAllText(FilePath, str.ToString, False)
        MessageBox.Show("File Created", "Success", MessageBoxButtons.OK)
    Catch ex As Exception
        MessageBox.Show(ex.Message, "Write Error", MessageBoxButtons.OK)
    End Try
End Sub

All that is left is to actually build the dataset and then pass it as well as the file name and path to the WriteDS2CSV sub.

Private Sub btnWriteCSV_Click( _
    ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles btnWriteCSV.Click

    BuildDS()
    WriteDS2CSV(ds, "C:\dsExport.csv")

End Sub

A handy little function to remove the name part of an email address.

Public Class Form1
    Public Function getNameFromEmail(ByVal strEmail As String) As String
        ' This purpose of this function is to return the
        ' name part of an email address. For instance
        ' joe@somewhere.com would return just joe.

        ' Use the IndexOf to find out how many characters
        ' in the @ sign is so I can use that number later
        ' to determine the amount of characters to select
        ' in the substring. 

        Dim i As Integer = strEmail.IndexOf("@")
        Dim newstring As String = strEmail.Substring(0, i)
        Return newstring
    End Function

    Private Sub Button1_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click

        Dim emailArray() As String = { _
            "me@somewhere.com", _
            "you@anywhere.com", _
            "them@nowhere.com"}

        For Each emailName As String In emailArray
            Dim strMess As String = CStr(getNameFromEmail(emailName))
            MessageBox.Show(strMess, "Email Name Test", _
            MessageBoxButtons.OK)
        Next
    End Sub
End Class

Imports System.Text.RegularExpressions
Public Class Form3
        Private Sub btnValidate_Click( _
            ByVal sender As System.Object, _
            ByVal e As System.EventArgs)
            Handles btnValidate.Click

        If EmailCheck(txtEmail.Text) = True Then
            MessageBox.Show("The email is valid.")
        Else
            MessageBox.Show("Email address is invalid")
        End If
    End Sub

       Function EmailCheck(ByVal Email As String) As Boolean
        Dim ValidEmail As String = _
        "^([0-9a-zA-Z]+[-._+&])*[0-9a-zA-Z]+@" & _
        "([-0-9a-zA-Z]+[.])+[a-zA-Z]{2,6}$"
        ' If the passed in email matched the
        ' RegEx pattern a true will get returned.
        Return Regex.IsMatch(Email, ValidEmail)
    End Function
End Class

I had a need for a function that would return the next birth date of a person without showing the actual birthday of that person to the end user. In the beginning I thought this was going to be a cinch to do. It wasn’t until I sat down to write the function that I realized it was not going to be quite as easy as I thought.

The trick is that when you are trying to figure out someone’s next birthday you have to figure out weather they have already had a birthday in the current year or not. So to start off I had to take a birthday like 1969, 9, 12 and bring it to the current year making it 2007, 9, 12 so that I could do a comparison.

Private Function NextBirthDay(ByVal Bday As Date) As Date
    Dim myDay As New Date(Date.Today.Year, Bday.Month, Bday.Day)
End Function

Next I had to figure out whether my new date had already passed the current date.

 If myDay <= Date.Today Then
     myDay = myDay.AddYears(1)
End If

If it had already passed I needed to add a year onto the new date so that it would return next years birthday date and not the current years birthday date. Obviously if it hadn’t already passed it is ok to return this years birthday date. The entire function looks like this

Private Function NextBirthDay(ByVal Bday As Date) As Date
    Dim myDay As New Date(Date.Today.Year, Bday.Month, Bday.Day)
    If myDay <= Date.Today Then
        myDay = myDay.AddYears(1)
    End If
    Return myDay
End Function

And can be called using NextBirthDay(BirthDate).ToShortDateString

Recently I created an Inventory Adjustment program, which loaded the entire inventory into a datagridview control from a table, allowed the user to edit the numbers and then save it back to the table. The specs required that new records not be added through this adjustment program but up until today I couldn’t find anyway to prevent what I thought was something we just had to live with when using the DGV. Not being able to prevent this "New" record was causing the application to throw an error every time someone moved beyond the last record and inserted a value into one of the fields in the New Record. So I added it to my list of things to figure out later list and moved on. Then today, coincidently, I was reading the Winforms post from Tim Mackley’s Mostly Net blog and ran across this post, which is where I learned about .DefaultView.AllowNew = False.

So I could take this	And make it this

Code behind

da = New SqlDataAdapter("Select * From tblInventory", Con)
da.TableMappings.Add("Table", "Inventory")
ds = New DataSet
Try
    da.Fill(ds)
    ds.Tables("Inventory").DefaultView.AllowNew = False
    dgvInventory.DataSource = ds.Tables("Inventory")
Catch ex As Exception
    MessageBox.Show(ex.Message, "Data Error", MessageBoxButtons.OK)
Finally
    da.Dispose()
    ds.Dispose()
End Try

A quick application to delete files older then a set number of days (or any interval).

Module Module1
    Sub Main()
        Fdelete()
    End Sub
    Private Sub Fdelete()
        ' Set directory to delete files
        Dim myDir As String = "C:\MyFiles\"
        Dim mydate As Date = Now
        For Each S As String In IO.Directory.GetFiles(myDir)
            If DateDiff( _
                    DateInterval.Day, _
                    IO.File.GetCreationTime(S), _
                    mydate) >= 7 Then
                ' Change the 7 to change the number of days to keep.
                ' Anything older then 7 days will be deleted. Also
                ' the date interval can be changed to whatever is
                ' appropriate for your needs.
                Try
                    IO.File.Delete(S)
                Catch ex As Exception
                    Console.WriteLine(ex.Message)
                End Try
            End If
        Next
    End Sub
End Module