Help me to Update data in Editable DataGrid

string sql = "SELECT * FROM tbUser";
myConnection = new SqlConnection(MyData.ConnectionString);
myDa = new SqlDataAdapter(sql,myConnection);
myDs = new DataSet();
myDa.Fill(myDs,"MyUser");
dataGrid1.DataSource=myDs;
dataGrid1.DataMember="MyUser";

that Ok!

But I want to save my data in datagrid when I change or add new record! (I maybe change some records!)

Help me!
Thanks before!