这是我的代码并出现未知错误：
private void dataGridView1_CellValueChanged(object sender,DataGridViewCellEventArgs e)
{
for (int i = 0; i < dataGridView1.Rows.Count; ++i)
{
object a = dataGridView1.Rows[i].Cells["price"].Value;
object b = dataGridView1.Rows[i].Cells["tedad"].Value;
double aNumber = 0;
double bNumber = 0;
if (a != null)
aNumber = Double.Parse(a.ToString());
if (b != null)
bNumber = Double.Parse(b.ToString());
dataGridView1.Rows[i].Cells["total"].Value = aNumber * bNumber;
dataGridView1.RefreshEdit();
}
decimal sum = dataGridView1.Rows.OfType<DataGridViewRow>()
.Sum(row => Convert.ToDecimal(row.Cells["total"].Value));
txtDate.Text = sum.ToString();
像OfType()这样的错误：
‘System.Windows.Forms.DataGridViewRowCollection’ does not contain a definition for ‘OfType’ and no extension method ‘OfType’ accepting a first argument of type ‘System.Windows.Forms.DataGridViewRowCollection’ WindowsFormsApplication1test
解决方法
确保你有：
using System.Linq;
>命名空间：System.Linq>程序集：System.Core(在System.Core.dll中)
