C # How to export an Excel file .?

Using system;
Using system. Collections. Generic;
Using system. text;
Using system. IO;
Using system. Data;
Using system. Windows. forms;
Using Microsoft. Office. InterOP. Excel;

Namespace property_management
{
Class Export
{
Private Static system. Windows. Forms. datagridview gridview;
Private Static system. Windows. Forms. progressbar toolstripprogressbar1;
Private Static timer time;
Private Static dataset objset = new dataset ();
Private Static savefiledialog = new savefiledialog ();
Private Static savefiledialog savefiledialog2 = new savefiledialog ();

Public static system. Windows. Forms. datagridview _ gridview
{
Get {return gridview ;}
Set {gridview = value ;}
}
Public static system. Windows. Forms. progressbar _ toolstripprogressbar1
{
Get {return toolstripprogressbar1 ;}
Set {toolstripprogressbar1 = value ;}
}
Public static timer _ time
{
Get {return time ;}
Set {time = value ;}
}
Public static dataset _ objset
{
Get {return objset ;}
Set {objset. Clear (); objset = value ;}
}

Public static void exporttoexcel2 ()
{
If (gridview. Rows. Count = 0)
{
MessageBox. Show ("no data is available for export! "," Prompt ", messageboxbuttons. OK, messageboxicon. information );
Return;
}
Else
{
Savefiledialog. Filter = "execl files (*. xls) | *. xls ";
Savefiledialog. filterindex = 0;
Savefiledialog. restoredirectory = true;
Savefiledialog. createprompt = true;
Savefiledialog. Title = "export file storage path ";
Savefiledialog. showdialog ();
String strname = savefiledialog. filename;
If (strname. length! = 0)
{
Toolstripprogressbar1.visible = true;
System. reflection. Missing Miss = system. reflection. Missing. value;
Microsoft. Office. InterOP. Excel. applicationclass Excel = new Microsoft. Office. InterOP. Excel. applicationclass ();
Excel. application. workbooks. Add (true );;
Excel. Visible = false; // if it is true, the Excel page is displayed during export.
If (Excel = NULL)
{
MessageBox. Show ("Excel cannot be started! "," Error ", messageboxbuttons. OK, messageboxicon. Error );
Return;
}
Microsoft. Office. InterOP. Excel. workbooks books = (Microsoft. Office. InterOP. Excel. workbooks) excel. workbooks;
Microsoft. Office. InterOP. Excel. Workbook book = (Microsoft. Office. InterOP. Excel. workbook) (books. Add (MISs ));
Microsoft. Office. InterOP. Excel. worksheet sheet = (Microsoft. Office. InterOP. Excel. worksheet) book. activesheet;
Sheet. Name = "test ";

// Generate the field name
For (INT I = 0; I <gridview. columncount; I ++)
{
Excel. cells [1, I + 1] = gridview. Columns [I]. headertext. tostring ();
}
// Fill in data
For (INT I = 0; I <gridview. rowcount; I ++)
{
For (Int J = 0; j <gridview. columncount; j ++)
{
If (gridview [J, I]. value. GetType () = typeof (string ))
{
Excel. cells [I + 2, J + 1] = "'" + gridview [J, I]. value. tostring ();
}
Else
{
Excel. cells [I + 2, J + 1] = gridview [J, I]. value. tostring ();

}
}
Toolstripprogressbar1.value + = 100/gridview. rowcount;
}
Sheet. saveas (strname, miss, Microsoft. Office. InterOP. Excel. xlsaveasaccessmode. xlnochange, miss );
Book. Close (false, miss, miss );
Books. Close ();
Excel. Quit ();
System. runtime. interopservices. Marshal. releasecomobject (sheet );
System. runtime. interopservices. Marshal. releasecomobject (book );
System. runtime. interopservices. Marshal. releasecomobject (books );
System. runtime. interopservices. Marshal. releasecomobject (Excel );
GC. Collect ();
MessageBox. Show ("data has been exported !! ");
Toolstripprogressbar1.value = 0;
Toolstripprogressbar1.visible = false;

System. Diagnostics. process. Start (strname );
}
}
}

}
}