一個winform程式，datagridview添加一列合計前兩列

DataTable dt
=
(DataTable)DataGridView1.DataSource;
dt.Columns.Add("newCol");
 
for
 (
int
 
i 
=
 0
; i 
<
dt.Rows.Count; i
++
)
{
 dt.Rows[i][
"
newCol
"
] 
=
int
.Parse(dt.Rows[i][
0
]) 
+
int
.Parse(dt.Rows[i][
1
]);}
DataGridView1.DataSource 
=
dt;