C#net listview控件获取表格数据，第二次不行，求救。

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private void LstShow_SelectedIndexChanged(object sender, EventArgs e)
{


data.Con.Open();
string strSql;
string ss;

ss = LstShow.SelectedItems[0].SubItems[1].Text.ToString();

strSql = " Select CustName,CustTel,CustCz,CustYb,CustLxr,CustAddress from Customer where custName='" + ss + "'";
OleDbCommand Com = new OleDbCommand(strSql, data.Con);
OleDbDataReader Reader;
Reader = Com.ExecuteReader();

if (Reader.Read())
{
txtName.Text = Reader["CustName"].ToString();
txtTel.Text = Reader["CustTel"].ToString();
txtCz.Text = Reader["CustCz"].ToString();
txtYb.Text = Reader["CustYb"].ToString();
txtLxr.Text = Reader["CustLxr"].ToString();
txtAddress.Text = Reader["CustAddress"].ToString();

data.Con.Close();

}


}

第一次点显示没问题，第二次点就出问题
ss = LstShow.SelectedItems[0].SubItems[1].Text.ToString();
InvalidArgument=“0”的值对于“index”无效。
参数名: index