dataGridView读写文本

constant con = new constant();

private void loadlistbox2()
{
dataGridView1.ColumnCount = 1;
string z;
if (File.Exists(".//allitems.txt"))
{
FileStream fs = new FileStream(".//allitems.txt", System.IO.FileMode.Open, System.IO.FileAccess.Read);

StreamReader sr = new StreamReader(fs, System.Text.Encoding.GetEncoding("utf-8"));
try
{
while (true)
{
z = sr.ReadLine();
if (z == null) break;
dataGridView1.Rows.Add(z);
}
}
finally
{
sr.Close();
fs.Dispose();
fs.Close();
}
}
}
string st = "";

private void savetestitem()
{
// dataGridView1.ColumnCount = 1;
if (File.Exists(".//allitems.txt"))
{
FileStream fs = new FileStream(".//allitems.txt", System.IO.FileMode.Open, System.IO.FileAccess.Write);

StreamWriter sr = new StreamWriter(fs, System.Text.Encoding.GetEncoding("utf-8"));
try
{
for (int i = 0; i < 22; i++)
{
for (int j = 0; j < 1; j++)
{
st = st + dataGridView1.Rows[i].Cells[j].Value;
}
sr.WriteLine(st);
st = "";

//for (int i = 0; i < dataGridView1.Rows.Count; i++)
//{
// sr.WriteLine(dataGridView1.Rows[i].Cells);
// }
}

}
finally
{
sr.Close();
fs.Dispose();
fs.Close();
}
}
}