I am a newbe and working on a program that will open excel and enter a value in the first open cell in column "A". I can make this code work in VBA, but VB.net is giving me the same success. Can anyone help?

Imports Microsoft.Office.Interop
Imports System.IO

Public Class Form1

Dim oEx As Excel.Workbook
Dim iEx As Excel.Application

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

iEx = New Excel.Application
iEx.Visible = True
oEx = iEx.Workbooks.Open("C:\Program Files\Nexulator\Schedule.xls")

End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
iEx.Range("A1").End(Excel.XlDirection.xlDown).Sele ct()
iEx.ActiveCell.Offset(1, 0).Select()
iEx.ActiveCell.Value = TextBox1.Text

End Sub

End Class

What happens when you run this?
Will it compile?
Does it generate any warnings when you compile it?

0x800A03EC

is the error I get.

come on... What is the text of the message? Who memorizes error numbers...

Below is the complete text of the error from Studio.net 2008

System.Runtime.InteropServices.COMException was unhandled
  ErrorCode=-2146827284
  Message="Exception from HRESULT: 0x800A03EC"
  Source=""
  StackTrace:
       at System.RuntimeType.ForwardCallToInvokeMember(Strin g memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData) at Microsoft.Office.Interop.Excel.Range.get_Offset(Ob ject RowOffset, Object ColumnOffset) at WindowsApplication1.Form1.Button2_Click(Object sender, EventArgs e) in C:\Documents and Settings\skalman\My Documents\Visual Studio 2008\Projects\excel5-23\excel5-23\Form1.vb:line 24 at System.Windows.Forms.Control.OnClick(EventArgs e) at System.Windows.Forms.Button.OnClick(EventArgs e) at System.Windows.Forms.Button.OnMouseUp(MouseEventAr gs mevent) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ButtonBase.WndProc(Message& m) at System.Windows.Forms.Button.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.O nMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.W ndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallba ck(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.DispatchM essageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager. System.Windows.Forms.UnsafeNativeMethods.IMsoCompo nentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.Run MessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.Run MessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run(ApplicationCo ntext context) at Microsoft.VisualBasic.ApplicationServices.WindowsF ormsApplicationBase.OnRun() at Microsoft.VisualBasic.ApplicationServices.WindowsF ormsApplicationBase.DoApplicationModel() at Microsoft.VisualBasic.ApplicationServices.WindowsF ormsApplicationBase.Run(String[] commandLine) at WindowsApplication1.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.Run UsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context( Object state) at System.Threading.ExecutionContext.Run(ExecutionCon text executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart()
  InnerException:

OK. That shows me that it is button 2 that is raising the error.
I am curious what "HRESULT" is, and where it is... But that is beside the point.

But in looking at button 2’s routine, I’m curious: Which statement raises the error?

If you examine iEx in the watch window do you find that it has actually opened the file?

Button1 actually opens the file, and button2 accesses the file. The code gets stuck at the following line:

iEx.Range("A1").End(Microsoft.Office.Interop.Excel .XlDirection.xlDown).Offset(1, 0).Select()

Then in the "immediate window" the following error is shown.

A first chance exception of type 'System.Runtime.InteropServices.COMException' occurred in mscorlib.dll

Try highlighting iEx, right-clicking the highlit text, and selecting to add it to the Watch Window.
Then go there and see if the variable actually references anything.

If it does, do the same thing, but after highlighting iEx.Range("A1")

There is no option in the context menu after right clicking for a watch window. I am working in VB.net 2008.

This works while the program is running. So in the IDE, set a breakpoint early-on in the program flow of the button click. Then, highlight the element you want to watch, and add it to the watch window. (You're gonna like this feature!)