Ouvrire excel

Bonjour,
j'ai un petit probleme je voudrais ouvrire une feuille excel et ecrire dedans mais impossible d'y arriver

Private Sub btnAppel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAppel.Click

Dim F_1 As Excel.Application

Dim F_2 As Excel.Workbook

Dim F_3 As Excel.Worksheet

F_1 = CType(CreateObject("Excel.Application"), Excel.Application)

F_2 = CType(F_1.Workbooks.Add, Excel.Workbook)

F_3 = CType(F_2.Worksheets(1), Excel.Worksheet)

F_3.Cells(1, 2) = 5000

F_3.Cells(2, 2) = 75

F_3.Cells(3, 1) = "Total"

F_3.Range("B3").Formula = "=Sum(R1C2:R2C2)"

F_3.Range("B3").Font.Bold = True

F_3.Application.Visible = True

F_3.SaveAs("C:\VBNET\feuille_1.xls")
End Sub

Essaye ceci dim F_1 as new excel.application dim F_2 as excel.workbook=F_1.workbooks.open dim F_3 as excel.worksheet=F_2.sheets(1) F_3.cells(1,2).value=5000 F_3.Cells(2, 2).value = 75 F_3.Cells(3, 1).value = "Total" F_3.Range("B3").Formula = "=Sum(R1C2:R2C2)" F_3.Range("B3").Font.Bold = True F_1.Visible = True F_2.SaveAs("C:\VBNET\feuille_1.xls")

dim F_2 as excel.workbook=F_1.workbooks.add

j'ai essayer mais il bloque sur

Dim F_2 As Excel.Workbook = F_1.Workbooks.Open

Dim F_2 As Excel.Workbook = F_1.Workbooks.add

poum :-)