How to refresh datagridview in window application

Hello, Manju Jd I think you are performing some insert or update operation on the data table after that you want to see the updated DataGridView.
 
now you need to create a method Named LoadData() or RefreshGrid() whatever you want it's your choice  
and  this method contains code 
 
private void RefreshGrid()
{
 
con = db.connection();//Here you can simply add your connection
con.Open(); 
SqlDataAdapter sd = new SqlDataAdapter("select *from TblDept",con);//write your Query to get data
dataGridView1.DataSource = null;//this is the main Part Here you need to clean all data that was presented in the Grid
DataSet ds = new DataSet();
sd.Fill(ds, "TblDept");
dataGridView1.DataSource = ds.Tables[0];//Now here we are Reloading the Gtrid 
} 
Here in this method we are removing all Old data from GridView and Adding Updated data on the Grid You can use your 
own code to load data on GridView  Important part is to remove All data from the grid by  
dataGridView1.DataSource = null; 
and Reload GridView With your Data 
you just need to call this method whenever you need to  Refresh the GridView it will work.
Thanks.. for Your Query