Inserting rows into existing Excel worksheet with OleDbConnection - oledb

Question

I'm building insert statements based on a list of data and a tab name. I have 4 tabs, the last 2 get data inserted successfully, the first 2 do not.
I commented out inserting into all tabs but one. The size of the excel file increases, but the rows are still blank. Any ideas?
Edit: For some reason, the Excel file I was using as a "blank template" had "empty" values in rows of the first 2 sheets. First one had "empty values" in the first 100K rows, seconds had empty values in the first 700-some rows. The data was being inserted after these rows, which explains why the file size was increasing. Now I'm getting "Operation must use an updateable query" when trying to insert.
Public Sub BuildReport(Of T)(tabName As String, dataList As IEnumerable(Of T))
'// Setup the connectionstring for Excel 2007+ XML format
'// http://www.connectionstrings.com/ace-oledb-12-0/
If ((tabName.EndsWith("$") = True AndAlso m_TabList.Contains(tabName) = False) OrElse m_TabList.Contains(tabName & "$") = False) Then
Throw New Exception(String.Format("The specified tab does not exist in the Excel spreadsheet: {0}", tabName))
End If
Using excelConn As New OleDbConnection(m_ConnectionString)
excelConn.Open()
Dim insertStatementList As IEnumerable(Of String) = BuildInsertStatement(Of T)(tabName, dataList)
Using excelCommand As New OleDbCommand()
excelCommand.CommandType = CommandType.Text
excelCommand.Connection = excelConn
For Each insertStatement In insertStatementList
excelCommand.CommandText = insertStatement
excelCommand.ExecuteNonQuery()
Next
End Using
End Using
End Sub
Private Function BuildInsertStatement(Of T)(tabName As String, dataList As IEnumerable(Of T)) As IEnumerable(Of String)
Dim insertStatementList As New List(Of String)
Dim insertStatement As New StringBuilder()
For Each dataItem As T In dataList
Dim props As PropertyInfo() = GetType(T).GetProperties()
insertStatement.Clear()
insertStatement.AppendFormat("INSERT INTO [{0}$] ", tabName)
Dim nameValueDictionary As New Dictionary(Of String, String)
For Each prop As PropertyInfo In props
Dim excelColumn As ExcelColumnAttribute = CType(prop.GetCustomAttributes(GetType(ExcelColumnAttribute), False).FirstOrDefault(), ExcelColumnAttribute)
If (excelColumn IsNot Nothing) Then
Dim value As Object = prop.GetValue(dataItem, Nothing)
If (value IsNot Nothing AndAlso value.GetType() <> GetType(Integer) _
AndAlso value.GetType() <> GetType(Double) _
AndAlso value.GetType() <> GetType(Decimal) _
AndAlso value.GetType() <> GetType(Boolean)) Then
value = String.Format("""{0}""", value)
ElseIf (value Is Nothing) Then
value = "NULL"
End If
nameValueDictionary.Add(excelColumn.ColumnName, value)
End If
Next
Dim columList As String = String.Join(",", nameValueDictionary.Keys)
Dim valueList As String = String.Join(",", nameValueDictionary.Select(Function(x) x.Value))
insertStatement.AppendFormat("({0}) ", columList)
insertStatement.AppendFormat("VALUES ({0})", valueList)
insertStatementList.Add(insertStatement.ToString())
Next
Return insertStatementList
End Function

Answer 1

For some reason, the Excel file I was using as a "blank template" had "empty" values in rows of the first 2 sheets. First one had "empty values" in the first 100K rows, second one had empty values in the first 700-some rows. The data was being inserted after these rows, which explains why the file size was increasing. Now I'm getting "Operation must use an updateable query" when trying to insert.
I found the answer to the second problem here: Operation must use an updateable query when updating excel sheet
Just needed to remove the "IMEX=1" from the extended properties of the connection string which I added in trying to troubleshoot the issue.