How to handle events like paging,editing,update,cancel in gridview,datagrid?

In the case of Edit event
DatagridName.EditItemIndex = e.Item.ItemIndex;
datagrid.DataSource="Tablename";
datagrid.DataBind();

In case of Cancel event

Datagridname.EditItemIndex = -1;
datagrid.DataSource="Tablename";
datagrid.DataBind();

In case of paging

Datagridname.CurrentPageIndex = e.NewPageIndex;
datagrid.DataSource="Tablename";
datagrid.DataBind();


In case of updating
Datagridname.EditItemIndex = -1;
datagrid.DataSource="Tablename";
datagrid.DataBind();