读取Daset结果，将某列用方法变量

现在是用这个方法读取出来了

 string day = dateTimePicker3.Value.ToString("yyyyMMdd");
            string str = dateTimePicker3.Value.ToString("yyyy-MM-dd HH:mm:ss");
            string end = dateTimePicker4.Value.ToString("yyyy-MM-dd HH:mm:ss");
            string path = @"SQL";
            string sql = ReadXmlStringFromFile("K.txt", "", path);
            sql = string.Format(sql, str, end, day, textEdit1.Text.Trim());
            ds = SqlHelper.ExecuteDataset(connstr, CommandType.Text, sql);
            gridControl1.DataSource = ds.Tables[0].DefaultView;
            this.gridView1.BestFitColumns();
想读取DataSet中add数据
用 sm方法将add数据变量后出，foreach 条件怎么写呢？
  foreach ()
            {
                try
                {
                    byte[] value = sm(row["add"].ToString());
                    n = BitConverter.ToDouble(value, 0);
                    row["add"] = n;
                }
                catch { }
            }

代码如下：

var scriptFile = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "query1.txt");
var sql = File.ReadAllText(scriptFile);
const string connectionString = @"Server=(localdb)\mssqllocaldb;Integrated Security=true;Database=Test";
var parameters = new List<SqlParameter>
{
    new SqlParameter("@A",txtKeyword.Text)
};
var ds = SqlHelper.ExecuteDataSet(connectionString, CommandType.Text, sql, parameters.ToArray());
var table = ds.Tables[0];
var rows = table.Rows;
for (var i = 0; i < rows.Count; i++)
{
   byte[] value = smethod(rows[i]["add"].ToString());
   num3 = BitConverter.ToDouble(value, 0);
    rows[i]["add"] = num3;
}

如有问题及时沟通

要修改DataTable中的单元格数据，不能使用foreach而应该用for循环语句，示例如下：

var scriptFile = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "query1.txt");
var sql = File.ReadAllText(scriptFile);
const string connectionString = @"Server=(localdb)\mssqllocaldb;Integrated Security=true;Database=Test";
var parameters = new List<SqlParameter>
{
    new SqlParameter("@A",txtKeyword.Text)
};
var ds = SqlHelper.ExecuteDataSet(connectionString, CommandType.Text, sql, parameters.ToArray());
var rows = ds.Tables[0].Rows;
for (var i = 0; i < rows.Count; i++)
{
    rows[i]["add"] = "你的内容";
}