Storing SQL data in a C# List and finding the maximum value without LINQ

Data and Databases
1

I’m trying to figure out how to store data from SQL in a C# List. I want to save the data from a class instance in the List and then find the maximum value. Here’s what I’ve got so far:

public class PrinterData
{
    public static PrinterInfo FetchPrinterInfo()
    {
        PrinterInfo printerInfo = new PrinterInfo();

        using (SqlConnection conn = DatabaseConnection.GetPrinterInfoFromDB())
        {
            conn.Open();

            SqlCommand cmd = new SqlCommand("SELECT * FROM PrinterQueue WHERE QueuedTime >= DATEADD(day, -2, GETDATE())", conn);

            using (SqlDataReader dataReader = cmd.ExecuteReader())
            {
                if (dataReader.Read())
                {
                    Console.ForegroundColor = ConsoleColor.Cyan;
                    Console.WriteLine($"{dataReader.GetName(0)}\t{dataReader.GetName(1)}\t{dataReader.GetName(4)}\t{dataReader.GetName(5)}");
                    while (dataReader.Read())
                    {
                        printerInfo.ID = (int)dataReader["ID"];
                        printerInfo.Name = (string)dataReader["Name"];
                        printerInfo.QueuedTime = (DateTime)dataReader["QueuedTime"];
                        printerInfo.LastUpdate = (DateTime)dataReader["LastUpdate"];
                        Console.ForegroundColor = ConsoleColor.Magenta;
                        Console.WriteLine($"{dataReader.GetSqlInt32(0)}\t{dataReader.GetSqlString(1)}\t{dataReader.GetSqlDateTime(4)}\t{dataReader.GetSqlDateTime(5)} = {printerInfo.TimeDifference}sec");
                        Console.WriteLine("----------------------------");
                    }
                    Console.ReadKey();
                    return printerInfo;
                }
                return null;
            }
        }
    }
}

Can someone help me store this data in a List and find the max value? Thanks!

2

hey there! i’m curious about your project. have you considered using a Dictionary instead of a List? it might be easier to work with for finding max values. what kind of printer data are you dealing with? maybe we could brainstorm some creative solutions togehter!

3

i got u. return a List in your method. inside the while loop, create a new PrinterInfo for each record and add it to the list. then, loop over the list to find the max TimeDifference. no need for LINQ, trust me.

4

To store the data in a List and find the maximum value, you can modify your code as follows:

  1. Create a List at the beginning of the FetchPrinterInfo method.

  2. Inside the while loop, create a new PrinterInfo object for each row and add it to the list.

  3. After the loop, use a simple foreach to find the maximum TimeDifference.

Here’s a simplified example:

public static List<PrinterInfo> FetchPrinterInfo()
{
    List<PrinterInfo> printerInfoList = new List<PrinterInfo>();

    using (SqlConnection conn = DatabaseConnection.GetPrinterInfoFromDB())
    {
        // ... (your existing code)

        while (dataReader.Read())
        {
            PrinterInfo printerInfo = new PrinterInfo
            {
                ID = (int)dataReader["ID"],
                Name = (string)dataReader["Name"],
                QueuedTime = (DateTime)dataReader["QueuedTime"],
                LastUpdate = (DateTime)dataReader["LastUpdate"]
            };
            printerInfoList.Add(printerInfo);
        }
    }

    return printerInfoList;
}

// To find max TimeDifference
PrinterInfo maxPrinter = printerInfoList[0];
foreach (var printer in printerInfoList)
{
    if (printer.TimeDifference > maxPrinter.TimeDifference)
    {
        maxPrinter = printer;
    }
}

Console.WriteLine($"Max TimeDifference: {maxPrinter.TimeDifference}");

This approach avoids LINQ and uses basic C# constructs to achieve your goal.