C#

string query = $"SELECT * FROM Data WHERE RawDataOrder = {Convert.ToInt32(label86.Text.Trim())}";

string query = "SELECT * FROM Data WHERE RawDataOrder = @orderId";

// Parse the UI value. Why you're using a label to "store" data
// used in your busniess rules is beyond my comprehension.
int orderId;

if (int.TryParse(label86.Text.Trim(), out orderId))
{
    // The parse worked! If execution gets to the next statement, orderId
    // has a valid value. Since the value is sitting in a variable, you
    // can now debug the code to see its value and what is being passed
    // to the SQL query.

    // Build the SQL Command
    using (SqlConnection conn = new SqlConnection("... connection string ..."))
    {

        using (SqlCommand comm = new SqlCommand(query, conn))
        {
            SqlParameter orderIdParam = new SqlParameter("@orderId", SqlDbType.Int);
            orderIdParam.Value = orderId;
            comm.Parameters.Add(orderIdParam);

            // You forgot to open the connection
            conn.Open();
            using (SqlDataReader reader = comm.ExecuteReader())
            {
                while (reader.Read())
                {
                    ...
                }
            }
        }
    }
}
else
{
    // The parse failed! You might want to tell the user about that.
    // If execution gets to here, the parse failed and you do not have a valid
    // orderId value.
}

Quote:

int.TryParse(label86.Text.Trim()

Iskander12345 wrote:

but when I use this filter, it often leads to blank chart

Try {
  MyStuff();
} catch (etc) { // etc. }

private decimal Highest(int bar, ValueDataSeries src, int length)
{
    if (bar < length)
        return 0.0m;

    decimal res = decimal.MinValue;

    for (int index = bar; index >= bar - (length - 1); index--)
    {
        if (src[index] > res)
            res = src[index];
    }

    return res;
}