using Microsoft.Office.Interop.Excel;
using Microsoft.Office.Core;
/// <summary>
/// Takes a CSV file and sucks it into the specified worksheet of this workbook at the specified range
/// </summary>
/// <param name="importFileName">Specifies the full path to the .CSV file to import</param>
/// <param name="destinationSheet">Excel.Worksheet object corresponding to the destination worksheet.</param>
/// <param name="destinationRange">Excel.Range object specifying the destination cell(s)</param>
/// <param name="columnDataTypes">Column data type specifier array. For the QueryTable.TextFileColumnDataTypes property.</param>
/// <param name="autoFitColumns">Specifies whether to do an AutoFit on all imported columns.</param>
public void ImportCSV(string importFileName, Excel.Worksheet destinationSheet,
  Excel.Range destinationRange, int[] columnDataTypes, bool autoFitColumns)
{
  destinationSheet.QueryTables.Add(
    "TEXT;" + Path.GetFullPath(importFileName),
  destinationRange, Type.Missing);
  destinationSheet.QueryTables[1].Name = Path.GetFileNameWithoutExtension(importFileName);
  destinationSheet.QueryTables[1].FieldNames = true;
  destinationSheet.QueryTables[1].RowNumbers = false;
  destinationSheet.QueryTables[1].FillAdjacentFormulas = false;
  destinationSheet.QueryTables[1].PreserveFormatting = true;
  destinationSheet.QueryTables[1].RefreshOnFileOpen = false;
  destinationSheet.QueryTables[1].RefreshStyle = XlCellInsertionMode.xlInsertDeleteCells;
  destinationSheet.QueryTables[1].SavePassword = false;
  destinationSheet.QueryTables[1].SaveData = true;
  destinationSheet.QueryTables[1].AdjustColumnWidth = true;
  destinationSheet.QueryTables[1].RefreshPeriod = 0;
  destinationSheet.QueryTables[1].TextFilePromptOnRefresh = false;
  destinationSheet.QueryTables[1].TextFilePlatform = 437;
  destinationSheet.QueryTables[1].TextFileStartRow = 1;
  destinationSheet.QueryTables[1].TextFileParseType = XlTextParsingType.xlDelimited;
  destinationSheet.QueryTables[1].TextFileTextQualifier = XlTextQualifier.xlTextQualifierDoubleQuote;
  destinationSheet.QueryTables[1].TextFileConsecutiveDelimiter = false;
  destinationSheet.QueryTables[1].TextFileTabDelimiter = false;
  destinationSheet.QueryTables[1].TextFileSemicolonDelimiter = false;
  destinationSheet.QueryTables[1].TextFileCommaDelimiter = true;
  destinationSheet.QueryTables[1].TextFileSpaceDelimiter = false;
  destinationSheet.QueryTables[1].TextFileColumnDataTypes = columnDataTypes;
  Logger.GetInstance().WriteLog("Importing data...");
  destinationSheet.QueryTables[1].Refresh(false);
  if (autoFitColumns==true)
    destinationSheet.QueryTables[1].Destination.EntireColumn.AutoFit();
  // cleanup
  this.ActiveSheet.QueryTables[1].Delete();
}

myOwnWorkbookClass.ImportCSV(
   @"C:\MyStuff\MyFile.CSV",
   (Excel.Worksheet)(MyWorkbook.Worksheets[1]),
   (Excel.Range)(((Excel.Worksheet)MyWorkbook.Worksheets[1]).get_Range("$A$7")),
   new int[] { 2, 2, 2, 2, 2 }, true);