在 子窗口里 定义事件 
public class childform 
{ 
public event EventHandler refreshData = null; 

protect void OnRefreshData() 
{ 
if( refreshData != null ) 
{ 
refreshData( this , eventArgs.Emptys); 
} 
} 

private void Save() 
{ 
//保存代码 
//刷新父窗口 
OnRefreshData(); 
} 
} 

//在父窗口里 
public class ParentForm 
{ 
private void Add() 
{ 
ChildForm form = new ChildForm(); 
form.refreshData += new refreshData ( refreshData ); 
form.ShowDialog(); 
} 
private void refreshData() 
{ 
//刷新Datagridview代码 
........ 
} 
}