How to import Excel with Password proteced file to Datagrid

Plz give me the suggestion.given below my code 

{ 

Microsoft.Office.Interop.Excel.Application excelApp = new Microsoft.Office.Interop.Excel.Application();

Microsoft.Office.Interop.Excel.Workbook excelBook = excelApp.Workbooks.Open(OpenDialogBox.FileName.ToString(), 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);

Microsoft.Office.Interop.Excel.Worksheet excelSheet = (Microsoft.Office.Interop.Excel.Worksheet)excelBook.Worksheets.get_Item(1); ;

Microsoft.Office.Interop.Excel.Range excelRange = excelSheet.UsedRange;

string strCellData = "";

double douCellData;

int rowCnt = 0;

int colCnt = 0;

DataTable dt = new DataTable();

for (colCnt = 1; colCnt <= excelRange.Columns.Count; colCnt++)

{

string strColumn = "";

strColumn = (string)(excelRange.Cells[1, colCnt] as Microsoft.Office.Interop.Excel.Range).Value2;

dt.Columns.Add(strColumn, typeof(string));

}

for (rowCnt = 2; rowCnt <= excelRange.Rows.Count; rowCnt++)

{

string strData = "";

for (colCnt = 1; colCnt <= excelRange.Columns.Count; colCnt++)

{

try

{

strCellData = (string)(excelRange.Cells[rowCnt, colCnt] as Microsoft.Office.Interop.Excel.Range).Value2;

strData += strCellData + "|";

}

catch (Exception ex)

{

douCellData = (excelRange.Cells[rowCnt, colCnt] as Microsoft.Office.Interop.Excel.Range).Value2;

strData += douCellData.ToString() + "|";

}

}

strData = strData.Remove(strData.Length - 1, 1);

dt.Rows.Add(strData.Split('|'));

}

dgcFeesEntry.ItemsSource = dt.DefaultView;

excelBook.Close(true, null, null);

excelApp.Quit();