public static System.object[,] ImportData(System.string fileName, System.string sourceName)

//create a new workbook
var workbook = new GrapeCity.Documents.Excel.Workbook();

// Open an excel file
var fileStream = GetResourceStream("xlsx\\AgingReport.xlsx");

// Get the possible import names in the file.
// The names[0] and names[1] are sheet names: "Aging Report", "Invoices".
// The names[2] and names[3] are table names: "'Aging Report'!tblAging", "Invoices!tblInvoices".
var names = GrapeCity.Documents.Excel.Workbook.GetNames(fileStream);

// Import the data of a table "'Aging Report'!tblAging" from the fileStream.
var data = GrapeCity.Documents.Excel.Workbook.ImportData(fileStream, names[2]);

// Assign the data to current workbook.
workbook.Worksheets[0].Range[0, 0, data.GetLength(0), data.GetLength(1)].Value = data;

// Save to an excel file
workbook.Save("importdatafortable.xlsx");

public static System.object[,] ImportData(
  System.string fileName,
  System.string worksheetName,
  System.int row,
  System.int column,
  System.int rowCount,
  System.int columnCount
)

static void TestPerformance()
{
  //create a new workbook
  var workbook = new GrapeCity.Documents.Excel.Workbook();

  workbook.ActiveSheet.Range["A:B"].ColumnWidth = 35;
  workbook.ActiveSheet.Range["A2:B2"].HorizontalAlignment = HorizontalAlignment.Right;

  //Number of times to read data.
  int count = 10;

  #region ImportData
  //Create a new workbook.        
  var importDataWorkbook = new GrapeCity.Documents.Excel.Workbook();
  importDataWorkbook.Worksheets.Add();

  //Total time consumed to import data "count-2" times.
  long importDataTotalTimeConsumed = 0;

  for (int i = 0; i < count; i++)
  {
     var importDataFileStream = GetResourceStream("xlsx\\AgingReport1.xlsx");

     //Start time to read Excel data.
     var importDatasw = new System.Diagnostics.Stopwatch();
     importDatasw.Start();

     //Import data of the range from the fileStream.              
     var data1 = GrapeCity.Documents.Excel.Workbook.ImportData(importDataFileStream, "Aging Report");
     var data2 = GrapeCity.Documents.Excel.Workbook.ImportData(importDataFileStream, "Invoices");            

     //End time to read Excel data.
     importDatasw.Stop();

     // Assign the data to current workbook
     importDataWorkbook.Worksheets[0].Range[0, 0, data1.GetLength(0), data1.GetLength(1)].Value = data1;
     importDataWorkbook.Worksheets[1].Range[0, 0, data2.GetLength(0), data2.GetLength(1)].Value = data2;    
     
     //The operating system has a cache to open the file, and it takes time to open the file for the first time.
     //For the accuracy of statistics, the time of the first and last time is removed.
     if (i > 0 && i < count - 1)
    {
         importDataTotalTimeConsumed += importDatasw.ElapsedMilliseconds;
    }
  }

  //Average time consumed to read data using "importData" method.
  double importDataTimeConsumed = (double)importDataTotalTimeConsumed / (count - 2);

  //Save to an excel file.
  importDataWorkbook.Save("Data1.xlsx");
  #endregion

  #region Open
  //Create a new workbook.
  var openWorkbook = new GrapeCity.Documents.Excel.Workbook();

  //Total time consumed to open Excel file "count-2" times.
  long openTotalTimeConsumed = 0;

  for (int i = 0; i < count; i++)
  {
      var openFileStream = GetResourceStream("xlsx\\AgingReport1.xlsx");

      //Start time to read Excel data.
      var opensw = new System.Diagnostics.Stopwatch();
      opensw.Start();

      //Import Excel data using "Open" Method.
      openWorkbook.Open(openFileStream);

      //End time to read Excel data.
      opensw.Stop();

      //The operating system has a cache to open the file, and it takes time to open the file for the first time.
      //For the accuracy of statistics, the time of the first and last time is removed.
      if (i > 0 && i < count - 1)
      {
          openTotalTimeConsumed += opensw.ElapsedMilliseconds;
      }
  }

   //Average time consumed to import Excel data using "Open" method.
   double openTimeConsumed = (double)openTotalTimeConsumed / (count - 2);

   //Save to an excel file
   openWorkbook.Save("Data2.xlsx");

   #endregion

   workbook.ActiveSheet.Range["A1"].Value = "Time consumed by ImportData method";
   workbook.ActiveSheet.Range["B1"].Value = "Time consumed by Open method";

   //Store the time information of ImportData mehod in cell A2.
   workbook.ActiveSheet.Range["A2"].Value = importDataTimeConsumed.ToString() + "ms";

   //Store the time information of Open mehod in cell B2.
   workbook.ActiveSheet.Range["B2"].Value = openTimeConsumed.ToString() + "ms";

   // Save to an excel file
   workbook.Save("importdataforrange.xlsx");
}