C # create (export from database) an Excel file (including InterOP. Excel. dll)

// Create an Excel application
Excel. Application xls_exp = NULL;
Int rowindex = 1;
Int colindex = 0;
// Create a workbook and a worksheet
Excel. _ workbook xls_book = NULL;
Excel. _ worksheet xls_sheet = NULL;
Try
{
Xls_exp = new excel. applicationclass ();
Xls_book = xls_exp.workbooks.add (true );
Xls_sheet = (Excel. _ worksheet) xls_book.activesheet;
// Obtain data
Datatable AA = getdata ();
// Assign the column name of the obtained table to the cell
Foreach (datacolumn Col in AA. columns)
{
Colindex ++;
Xls_exp.cells [1, colindex] = col. columnname;
// Horizontal Alignment
Xls_sheet.get_range (xls_exp.cells [1, colindex], xls_exp.cells [1, colindex]). horizontalalignment = excel. xlvalign. xlvaligncenter;
// Vertical Alignment
Xls_sheet.get_range (xls_exp.cells [1, colindex], xls_exp.cells [1, colindex]). verticalignment = excel. xlvalign. xlvaligncenter;
// Adaptive Row Height and column width
// Xls_sheet.cells.rows.autofill ();
// Xls_sheet.cells.columns.autofill ();
}
// Process data in the same way
Foreach (datarow row in AA. Rows)
{
Rowindex ++;
Colindex = 0;
Foreach (datacolumn Col in AA. columns)
{
Colindex ++;
Switch (row [col. columnname]. GetType (). tostring ())
{
// Character
Case ("system. String "):
// Set the number format to text
Xls_sheet.get_range (xls_exp.cells [rowindex, colindex], xls_exp.cells [rowindex, colindex]). numberformatlocal = "@";
// Horizontal Alignment
Xls_sheet.get_range (xls_exp.cells [rowindex, colindex], xls_exp.cells [rowindex, colindex]). horizontalalignment = excel. xlvalign. xlvaligncenter;
// Vertical Alignment
Xls_sheet.get_range (xls_exp.cells [rowindex, colindex], xls_exp.cells [rowindex, colindex]). verticalignment = excel. xlvalign. xlvaligncenter;
Break;
// Date
Case ("system. datetime "):
// Set the number format to yyyy-mm-dd hh: mm: SS date
Xls_sheet.get_range (xls_exp.cells [rowindex, colindex], xls_exp.cells [rowindex, colindex]). numberformatlocal = "YYYY-MM-DD hh: mm: SS ";
Break;
}
// Assign values to cells
Xls_exp.cells [rowindex, colindex] = row [col. columnname];

}
}
// Invisible, that is, background processing
Xls_exp.visible = true;
Catch (exception ERR)
{
MessageBox. Show (ERR. Message );
}
// Finally
//{
// Xls_exp.quit ();
//}