Programmatically Insert to Existing Excel File using C#

Programmatically Insert to Existing Excel File using C#

I got a requirement to do an insertion of data in to an excel file. I have used Microsoft.Office.Interop.Excel to do it using C#. When I search I can able to find lot of examples in the internet stating how to insert data. But they are all creating new Excel file or Sheet. But my requirement is, if the file already exists we need to make use of that.

And also, if the sheet name I am specifying already exists then it should use the same sheet.(i..e I need to insert data at the end).

Here is the code which will do the insertion in an already exists excel file. It may be useful for someone.

private static Microsoft.Office.Interop.Excel.Workbook mWorkBook;
private static Microsoft.Office.Interop.Excel.Sheets mWorkSheets;
private static Microsoft.Office.Interop.Excel.Worksheet mWSheet1;
private static Microsoft.Office.Interop.Excel.Application oXL;
public static void ReadExistingExcel()
{
string path = @"C:\Tool\Reports1.xls";
oXL = new Microsoft.Office.Interop.Excel.Application();
oXL.Visible = true;
oXL.DisplayAlerts = false;
mWorkBook = oXL.Workbooks.Open(path, 0, false, 5, "", "", false, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "", true, false, 0, true, false, false);
//Get all the sheets in the workbook
mWorkSheets = mWorkBook.Worksheets;
//Get the allready exists sheet
mWSheet1 = (Microsoft.Office.Interop.Excel.Worksheet)mWorkSheets.get_Item("Sheet1");
Microsoft.Office.Interop.Excel.Range range= mWSheet1.UsedRange;
int colCount = range.Columns.Count;
int rowCount= range.Rows.Count;
for (int index = 1; index < 15; index++)
{
mWSheet1.Cells[rowCount + index, 1] = rowCount +index;
mWSheet1.Cells[rowCount + index, 2] = "New Item"+index;
}
mWorkBook.SaveAs(path, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal,
Missing.Value, Missing.Value, Missing.Value, Missing.Value,Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive,
Missing.Value, Missing.Value, Missing.Value,
Missing.Value, Missing.Value);
mWorkBook.Close(Missing.Value, Missing.Value, Missing.Value);
mWSheet1 = null;
mWorkBook = null;
oXL.Quit();
GC.WaitForPendingFinalizers();
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();
}

If you need to create a new Sheet use the following code.

oSheet = (Excel.Worksheet)oWB.Sheets.Add(Missing.Value, Missing.Value, Missing.Value, Missing.Value);

oSheet.Name = SheetName;