Tag: Visual Basic

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Populating Excel from Dataset

Exporting a set of data to an Excel spreadsheet is a very common task. Here is an easy method for outputting any dataset with any number of tables to Excel.

Private Sub ExportGenericExcel(ByVal Title As String, ByVal Source As DataSet)
‘Should add reference in Visual Studio to Microsoft Excel
Dim oExcel As Object
Dim oBook As Object
Dim oSheet As Object
Dim r, s, t As Integer
‘Start a new workbook in Excel.
oExcel = CreateObject(“Excel.Application”)
oBook = oExcel.Workbooks.Add
Dim sar As DataSet
sar = Source
For s = 0 To sar.Tables.Count – 1
If s > 2 Then oBook.Worksheets.Add()
oSheet = oBook.Worksheets(s + 1)
oSheet.Name = Title & s.ToString
oSheet.Select()
‘Add Column Names as first row in bold
For t = 0 To sar.Tables(s).Columns.Count – 1
oSheet.Cells(1, t + 1) = sar.Tables(s).Columns.Item(t).ColumnName
oSheet.cells(1, t + 1).font.bold = True
Next
For r = 0 To sar.Tables(s).Rows.Count – 1
For t = 0 To sar.Tables(s).Columns.Count – 1
oSheet.Cells(r + 2, t + 1) = sar.Tables(s).Rows(r).Item(t)
If r = 0 And t = 1 Then
oSheet.cells(r + 2, t + 1).Select()
oExcel.ActiveWindow.FreezePanes = True
End If
Next
Next
Next
‘ Make sure Excel is visible and give the user control of Excel’s lifetime.
oExcel.Visible = True
oExcel.UserControl = True
‘ Make sure that you release object references.
oSheet = Nothing
oBook = Nothing
‘oExcel.Quit() Without this the Excel process will remain open as long as the calling program is running
oExcel = Nothing
End Sub

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Private Sub ExportGenericExcel(ByVal Title As String, ByVal Source As DataSet)
‘Should add reference in Visual Studio to Microsoft Excel
Dim oExcel As Object
Dim oBook As Object
Dim oSheet As Object
Dim r, s, t As Integer
‘Start a new workbook in Excel.
oExcel = CreateObject(“Excel.Application”)
oBook = oExcel.Workbooks.Add
Dim sar As DataSet
sar = Source
For s = 0 To sar.Tables.Count – 1
‘oBook.Worksheets.Add()
oSheet = oBook.Worksheets(s + 1)
oSheet.Name = Title & s.ToString
oSheet.Select()
‘MsgBox(oSheet.name)
‘Transfer the array to the worksheet starting at cell A2.
‘oSheet.Range(“A2”).Resize(100, 3).Value = DataArray
For t = 0 To sar.Tables(s).Columns.Count – 1
oSheet.Cells(1, t + 1) = sar.Tables(s).Columns.Item(t).ColumnName
oSheet.cells(1, t + 1).font.bold = True
Next
For r = 0 To sar.Tables(s).Rows.Count – 1
For t = 0 To sar.Tables(s).Columns.Count – 1
oSheet.Cells(r + 2, t + 1) = sar.Tables(s).Rows(r).Item(t)
If r = 0 And t = 1 Then
oSheet.cells(r + 2, t + 1).Select()
oExcel.ActiveWindow.FreezePanes = True
End If
Next
Next
‘oSheet.Cells(2, 2).Select()
‘oExcel.ActiveWindow.FreezePanes = True
Next
‘ Make sure Excel is visible and give the user control
‘ of Excel’s lifetime.
oExcel.Visible = True
oExcel.UserControl = True
‘ Make sure that you release object references.
oSheet = Nothing
oBook = Nothing
oExcel.Quit()
oExcel = Nothing
End Sub

Sub ExportGenericExcel(ByVal Title As String, ByVal Source As DataSet)

‘Should add reference in Visual Studio to Microsoft Excel
Dim oExcel As Object
Dim oBook As Object
Dim oSheet As Object
Dim r, s, t As Integer
‘Start a new workbook in Excel.
oExcel = CreateObject(“Excel.Application”)
oBook = oExcel.Workbooks.Add
Dim sar As DataSet
sar = Source
For s = 0 To sar.Tables.Count – 1
‘oBook.Worksheets.Add()
oSheet = oBook.Worksheets(s + 1)
oSheet.Name = Title & s.ToString
oSheet.Select()
‘MsgBox(oSheet.name)
‘Transfer the array to the worksheet starting at cell A2.
‘oSheet.Range(“A2”).Resize(100, 3).Value = DataArray
For t = 0 To sar.Tables(s).Columns.Count – 1
oSheet.Cells(1, t + 1) = sar.Tables(s).Columns.Item(t).ColumnName
oSheet.cells(1, t + 1).font.bold = True
Next
For r = 0 To sar.Tables(s).Rows.Count – 1
For t = 0 To sar.Tables(s).Columns.Count – 1
oSheet.Cells(r + 2, t + 1) = sar.Tables(s).Rows(r).Item(t)
If r = 0 And t = 1 Then
oSheet.cells(r + 2, t + 1).Select()
oExcel.ActiveWindow.FreezePanes = True
End If
Next
Next
‘oSheet.Cells(2, 2).Select()
‘oExcel.ActiveWindow.FreezePanes = True
Next
‘ Make sure Excel is visible and give the user control
‘ of Excel’s lifetime.
oExcel.Visible = True
oExcel.UserControl = True
‘ Make sure that you release object references.
oSheet = Nothing
oBook = Nothing
oExcel.Quit()
oExcel = Nothing
End Private Sub ExportGenericExcel(ByVal Title As String, ByVal Source As DataSet)
‘Should add reference in Visual Studio to Microsoft Excel
Dim oExcel As Object
Dim oBook As Object
Dim oSheet As Object
Dim r, s, t As Integer
‘Start a new workbook in Excel.
oExcel = CreateObject(“Excel.Application”)
oBook = oExcel.Workbooks.Add
Dim sar As DataSet
sar = Source
For s = 0 To sar.Tables.Count – 1
‘oBook.Worksheets.Add()
oSheet = oBook.Worksheets(s + 1)
oSheet.Name = Title & s.ToString
oSheet.Select()
‘MsgBox(oSheet.name)
‘Transfer the array to the worksheet starting at cell A2.
‘oSheet.Range(“A2”).Resize(100, 3).Value = DataArray
For t = 0 To sar.Tables(s).Columns.Count – 1
oSheet.Cells(1, t + 1) = sar.Tables(s).Columns.Item(t).ColumnName
oSheet.cells(1, t + 1).font.bold = True
Next
For r = 0 To sar.Tables(s).Rows.Count – 1
For t = 0 To sar.Tables(s).Columns.Count – 1
oSheet.Cells(r + 2, t + 1) = sar.Tables(s).Rows(r).Item(t)
If r = 0 And t = 1 Then
oSheet.cells(r + 2, t + 1).Select()
oExcel.ActiveWindow.FreezePanes = True
End If
Next
Next
‘oSheet.Cells(2, 2).Select()
‘oExcel.ActiveWindow.FreezePanes = True
Next
‘ Make sure Excel is visible and give the user control
‘ of Excel’s lifetime.
oExcel.Visible = True
oExcel.UserControl = True
‘ Make sure that you release object references.
oSheet = Nothing
oBook = Nothing
oExcel.Quit()
oExcel = Nothing
End Sub
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Manually Populating Datarows

I like using datarows and datatables as multi-dimensioal array structures. Their most common use seems to be iterating through datatables, but you can also populate them as you would an array but with strongly typed values. This is a demonstration of populating a datarow with a combination of datareader, datarow and direct assignment. I have encapsulated it in a function to avoid using public variables.

Function GetOrderData(ByVal rAccount As DataRow, ByVal rOrder As DataRow) As DataRow

Dim strErrorMessage As String
Dim intExitCode As Integer
Dim StartDate As Date
Dim EndDate As Date

Try

Dim strConnectionString As String = “Server=DBSERVER;Database=DB;User ID=Program;Password=Password;Trusted_Connection=False”
Dim myConnection As SqlConnection = New SqlConnection(strConnectionString)
myConnection.Open()

Dim myCommand As SqlCommand = New SqlCommand(“usp_sel_Query”, myConnection)
Dim mySqlReader As SqlDataReader

‘Get original account info
myCommand.CommandType = CommandType.StoredProcedure
myCommand.Parameters.Add(“@ID”, rAccount.Item(“ID”))

mySqlReader = myCommand.ExecuteReader
Do

While mySqlReader.Read()

If IsDBNull(mySqlReader(“Collected”)) Then rOrder.Item(“Collected”) = 0 Else rOrder.Item(“Collected”) = mySqlReader(“Collected”)
If IsDBNull(mySqlReader(“EndDate”)) Then EndDate = Nothing Else EndDate = mySqlReader(“EndDate”)
rOrder.Item(“CustomerID”) = rAccount.Item(“CustomerID”)
rOrder.Item(“OrderDate”) = rAccount.Item(“OrderDate”)
rOrder.Item(“AccountDate”) = rAccount.Item(“AcctAssign”)
rOrder.Item(“Orders”) = 1 + 5
rOrder.Item(“Package”) = rAccount.Item(“Package”)

End While

Loop While mySqlReader.NextResult()

mySqlReader.Close()
myConnection.Close()

GetOrderData = rOrder

Catch ex As Exception
strErrorMessage = ex.Message
intExitCode = Err.Number()

Finally

If intExitCode <> 0 Then

MsgBox(“Error ” & intExitCode & ” occurred for CustomerID ” & rAccount.Item(“CustomerID”) & “. ” & strErrorMessage, MsgBoxStyle.OKOnly + MsgBoxStyle.Critical)

End If

End Try

End Function

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Create Custom DataTable

Datatables are very useful containers for data and have a very familiar format for database programmers. The most common method for creating them is using a DataAdapter. When using a DataAdapter, you are obliged to use the data schema of the query used to fill the datatable. Here is a method in VB.NET for creating a datatable with exactly the columns and attributes called for in your program.

Private Function CreateOrdersTable() As DataTable
Dim strErrorMessage As String
Dim intExitCode As Integer
Try
Dim OrdersTable As DataTable
OrdersTable = New DataTable(“Orders”)

Dim Cost As DataColumn = New DataColumn
Cost.ColumnName = “Cost”
Cost.DataType = System.Type.GetType(“System.Decimal”)
OrdersTable.Columns.Add(Cost)

Dim Package As DataColumn = New DataColumn
Package.ColumnName = “Package”
Package.DataType = System.Type.GetType(“System.String”)
OrdersTable.Columns.Add(Package)

Dim CustomerID As DataColumn = New DataColumn
CustomerID.ColumnName = “CustomerID”
CustomerID.DataType = System.Type.GetType(“System.Int32”)
OrdersTable.Columns.Add(CustomerID)

Dim AccountDate As DataColumn = New DataColumn
AccountDate.ColumnName = “AccountDate”
AccountDate.DataType = System.Type.GetType(“System.DateTime”)
OrdersTable.Columns.Add(AccountDate)

CreateOrdersTable = OrdersTable

Catch ex As Exception
strErrorMessage = ex.Message
intExitCode = Err.Number()
Finally
If intExitCode <> 0 Then
MsgBox(“Error ” & intExitCode & ” occurred. ” & strErrorMessage, MsgBoxStyle.OKOnly + MsgBoxStyle.Critical)
End If
End Try

End Function