How to shuffle an array VS Windows Form Application? - C# Discussion Boards

Re: How to copy DataTable contents into SQLite table?

26-Jul-21 21:16

I changed the InserData() method:

public void InsertData()
{
    SQLiteConnection con = new SQLiteConnection(@"Data Source=" + databaseName);
    con.Open();
    SQLiteDataAdapter dAdapter = new SQLiteDataAdapter("INSERT INTO MyTable", con);
    SQLiteCommandBuilder cmdBuilder = new SQLiteCommandBuilder();
    cmdBuilder.DataAdapter = dAdapter;
    dAdapter.Update(dt);
    con.Close();
}

It still doesn't work. Note that DataTable headers and column names in SQLite table are the same.
What query should I use?

modified 27-Jul-21 3:24am.

Alex Dunlop26-Jul-21 22:58

Re: How to copy DataTable contents into SQLite table?

26-Jul-21 22:58

Is there any way to transfer them from DataTable to SQLite table at once and quickly?
I can use For loop but my data is huge (40 columns and around 30000 rows).

OriginalGriff26-Jul-21 23:09

Re: How to copy DataTable contents into SQLite table?

26-Jul-21 23:09

Yes. And if you follow the link I gave you it tells you how to!

Alex Dunlop27-Jul-21 0:39

Re: How to copy DataTable contents into SQLite table?

27-Jul-21 0:39

In the Link you provided, there is a string parameter for queryString. I need to INSERT data. What query should I use for transferring all cell information into SQLite?

Richard Andrew x6428-Jul-21 2:36

Richard Andrew x64

28-Jul-21 2:36

It looks to me like the query string should be the SELECT query that pulls the data you want to transfer.

The difficult we do right away...
...the impossible takes slightly longer.

RTD communication error (COM) / .ConnectData(Int32 topicId, Object[]& parameters, Boolean& newValue)

Juliano Zucatti26-Jul-21 10:14

Juliano Zucatti

26-Jul-21 10:14

I created a client to communicate with RTD server, my knowledge is small in C# I have greater in JAVA, but I didn't find anything likely to be used in JAVA, I'm using this example of a C# client

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Threading;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;
namespace DotNet2
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");

            chamaMetodo("RTDTrading.RTDServer");
        }

        private static void chamaMetodo(string v)
        {
                       
            RtdClient rtd = new RtdClient(v);
            Console.WriteLine("rtd:"+rtd);
            
            object[] param = new Object[2];
            param[0] = "DOLFUT_F_0";
            param[1] = "HOR";
            Object ret = rtd.GetValue(param);
            Console.WriteLine("ret:"+ret);
        }
    }

}

Class Interface que monta a comunicação:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Threading;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;

namespace DotNet2
{
    public interface IRtdClient
    {
        object GetValue(params object[] args);
    }

    public class RtdClient : IRtdClient
    {
        readonly string _rtdProgId;
        static IRtdServer _rtdServer;
        

        public RtdClient(string rtdProgId)
        {
            _rtdProgId = rtdProgId;
        }

        public object GetValue(params object[] args)
        {
            
            const int topicCount = 1;
            var rnd = new Random();
            var topicId = rnd.Next(int.MaxValue);
            var rtdServer = GetRtdServer();
            Console.WriteLine("TopicID "+topicId+" args:"+args[0]+" args2:"+args[1]);
            
            rtdServer.ConnectData(topicId, args, true);

            object val = null;
            while (val == null)
            {
                var alive = rtdServer.Heartbeat();
                
                if (alive != 1)
                    GetRtdServer();
                else
                {
                    //var refresh = new object[0,0];
                    var refresh = rtdServer.RefreshData(topicCount);
                    if (refresh.Length <= 0) continue;

                    if (refresh[0, 0].ToString() == topicId.ToString())
                    {
                        val = refresh[1, 0];
                    }
                }
            }

            rtdServer.DisconnectData(topicId);

            return val;
        }

        IRtdServer GetRtdServer()
        {
            if (_rtdServer == null)
            {
                Type rtd = Type.GetTypeFromProgID(_rtdProgId);
                _rtdServer = (IRtdServer)Activator.CreateInstance(rtd);
            }
            return _rtdServer;
        }
    }

    [ComImport,
        TypeLibType((short)0x1040),
        Guid("EC0E6191-DB51-11D3-8F3E-00C04F3651B8")]
    public interface IRtdServer
    {
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(10)]
        int ServerStart([In, MarshalAs(UnmanagedType.Interface)] IRTDUpdateEvent callback);

        [return: MarshalAs(UnmanagedType.Struct)]
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(11)]
        object ConnectData([In] int topicId, [In, MarshalAs(UnmanagedType.SafeArray,
                                                SafeArraySubType = VarEnum.VT_VARIANT)] ref object[] parameters, [In, Out] ref bool newValue);

        [return: MarshalAs(UnmanagedType.SafeArray, SafeArraySubType = VarEnum.VT_VARIANT)]
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(12)]
        object[,] RefreshData([In, Out] ref int topicCount);

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(13)]
        void DisconnectData([In] int topicId);

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(14)]
        int Heartbeat();

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(15)]
        void ServerTerminate();
    }

    [ComImport,
        TypeLibType((short)0x1040),
        Guid("A43788C1-D91B-11D3-8F39-00C04F3651B8")]
    public interface IRTDUpdateEvent
    {
        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(10),
            PreserveSig]
        void UpdateNotify();

        [DispId(11)]
        int HeartbeatInterval
        {
            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(11)]
            get; [param: In]
            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(11)]
            set;
        }

        [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), DispId(12)]
        void Disconnect();
    }

}

But I'm getting this error, in the method call:rtdServer.ConnectData(topicId, args, true);

Unhandled exception. System.Runtime.InteropServices.COMException (0x8000FFFF): Falha catastrófica (0x8000FFFF (E_UNEXPECTED))
at DotNet2.IRtdServer.ConnectData(Int32 topicId, Object[]& parameters, Boolean& newValue)

Is anyone aware of the error?

modified 26-Jul-21 18:00pm.

How to shuffle an array VS Windows Form Application?

Sofi081326-Jul-21 0:26

Sofi0813

26-Jul-21 0:26

I need help C# VS 2019 Windows Form Application. I am new!!!I want to shuffle an integer array and use the values on my buttons when I click on my ButtonNext. I have got some tips but not working.
- e is not accepted?
- shuffledArray[] is not accepted?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;
using System.Windows.Forms;
namespace Dari1MainPage_v002
{
public partial class Exercise1 : Form
{
public Exercise1()
{
InitializeComponent();
}
private void btnNext_Click(object sender, EventArgs e)
{
int[] originalArray = { 0, 1, 2, 3 };
var rng = new Random();
var shuffledArray = originalArray.OrderBy(e => rng.NextDouble()).ToArray();

btnAns1.Text = shuffledArray[0];
btnAns2.Text = shuffledArray[1];
btnAns3.Text = shuffledArray[2];
btnAns4.Text = shuffledArray[3];
}
}
}

Re: How to shuffle an array VS Windows Form Application?

OriginalGriff26-Jul-21 0:40

Re: How to shuffle an array VS Windows Form Application?

26-Jul-21 0:40

That code doesn't compile for two reasons:
1) It won't let you use e inside the OrderBy as it's already declared as a parameter to the function.
2) You can't implicitly convert an integer to a string.
Try this:

int[] originalArray = { 0, 1, 2, 3 };
var rng = new Random();
var shuffledArray = originalArray.OrderBy(oa => rng.NextDouble()).ToArray();

btnAns1.Text = shuffledArray[0].ToString();
btnAns2.Text = shuffledArray[1].ToString();
btnAns3.Text = shuffledArray[2].ToString();
btnAns4.Text = shuffledArray[3].ToString();

Sofi081326-Jul-21 1:22

Sofi0813

26-Jul-21 1:22

Thanks it is working fine now

Re: How to shuffle an array VS Windows Form Application?

Richard MacCutchan26-Jul-21 0:42

Richard MacCutchan

26-Jul-21 0:42

The values in your array are integers, but a Button.Text property requires a string. So add a call to ToString on your numbers thus:

btnAns1.Text = shuffledArray[0].ToString();
btnAns2.Text = shuffledArray[1].ToString();
btnAns3.Text = shuffledArray[2].ToString();
btnAns4.Text = shuffledArray[3].ToString();

How to find average value for duplicate keys in Dictionary?

Alex Dunlop24-Jul-21 4:29

Re: How to find average value for duplicate keys in Dictionary?

24-Jul-21 4:29

Hi,
I want to explain my real-world problem with a simple example. I have these names and their corresponding marks:
Alex -----> 20
Alexis -----> 12.5
John -----> 16.3
Alex -----> 17.5
John -----> 19

I can sum each person's mark using Dictionary but I don't know how to find the average for them.
If there is any better way to find the average else than Dictionary, please guide me.
Thanks.

Alex Dunlop24-Jul-21 6:29

Re: How to find average value for duplicate keys in Dictionary?

24-Jul-21 6:29

I finally could solve it by using two dictionaries. One for unique keys and another for any duplicates. After that, I could calculate the final result based on those two dictionaries. Smile | :)

Gerry Schmitz24-Jul-21 6:44

Gerry Schmitz

24-Jul-21 6:44

You could have added a counter to the "values" side of the dictionary: e.g.

Dictionary<string, Tuple<int, int>>.

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Re: How to find average value for duplicate keys in Dictionary?

OriginalGriff24-Jul-21 6:47

Re: How to find average value for duplicate keys in Dictionary?

24-Jul-21 6:47

The simplest way is to create a dictionary that holds a tupple:

Dictionary<string, (int, double)> dict = new Dictionary<string, (int, double)>();

Then when you add your items, you check if the key name is already there.
If it isn't add it with a int of 1 as the count, and a double which is the value:

dict.Add("Alex", (1, 20.0));

If it is, increment the integer, and sum the new value :

dict["Alex"] = (dict["Alex"].Item1 + 1, dict["Alex"].Item2 + 17.5);

You can then work out the averages very simply in a loop when all items are added.

BillWoodruff28-Jul-21 3:11

BillWoodruff

28-Jul-21 3:11

In C# generic Dictionaries do not allow duplicate Keys.

You could use another data structure; for example:

List<KeyValuePair<string, double>> ScoreList = new List<KeyValuePair<string, double>>();

Once you've got all your data entered, to average use Linq:

double averageOfAll = ScoreList.Average(kvp => kvp.Value);

«The mind is not a vessel to be filled but a fire to be kindled» Plutarch

Efficient method to build a CSV string

Vikas Mishra Jul202123-Jul-21 10:46

Vikas Mishra Jul2021

23-Jul-21 10:46

Hello Guys,

I need to build a comma separated string from 100+ different field(few are string and others are either int or decimal), here each field should be in specific order:
Solution i can imagine are:
1)Define a string builder and Call methods for each field to fill the string builder
2)build each item in list and then call for string.join
3) Call for string.Format...

I am not able to decide which method is more efficient and maintainable.

Any thought on this? may be better approach ?

Re: Efficient method to build a CSV string

Dave Kreskowiak23-Jul-21 11:59

Dave Kreskowiak

23-Jul-21 11:59

There are plenty of CSV libraries in Nuget. Why roll another one when it's been a repeatedly solved problem?

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Re: Efficient method to build a CSV string

Richard Andrew x6423-Jul-21 12:18

Richard Andrew x64

23-Jul-21 12:18

In addition to the excellent advice that Dave gave you, there is an easy way to join any number of fields with a common delimiter.

If you have the fields in an array or a List<> object, you can call string.Join(",", Fields.ToArray())

That method gives you a single string with all the elements separated by commas.

The difficult we do right away...
...the impossible takes slightly longer.

Re: Efficient method to build a CSV string

Gerry Schmitz24-Jul-21 6:20

Gerry Schmitz

24-Jul-21 6:20

Depends on where the "100+" fields are coming from. Trying to spec a solution to an ill-defined problem.

(I'm currently using Excel to create "data tables" which are then exported as CSV files for use as embedded resources in another app).

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

How to get double value in string format?

Alex Dunlop23-Jul-21 7:48

23-Jul-21 7:48

Hi,
I'm using DevExpress Spreadsheet. I divide a number by another number and convert the result to string and then I put it in a cell in spreadsheet. The problem is that the output is an integer, not a double value. How can I fix it?

OriginalGriff23-Jul-21 8:12

23-Jul-21 8:12

Try:

int x = 95;
int y = 3;
string str = ((double) (x / y)).ToString("F2");

int x = 95;
int y = 3;
string str = ((double) x / (double) y).ToString("F2");

Depending on the result you wanted.

Alex Dunlop29-Jul-21 6:20

29-Jul-21 6:20

I did test it:

MessageBox.Show(((double)(31 / 2)).ToString("F2"));

But the result shows 15.00
How can I solve it?

OriginalGriff29-Jul-21 6:32

29-Jul-21 6:32

Use the other one?

When you write a numeric constant with no fractional component: 31 say, or 2 you are defining an integer constant. Which means that any operations you do with them use integer math: integer divided by integer gives the same type: integer - and any fractional part is discarded.
So 31 / 2 is 15 and casting the result to a double gives the double equivalent or the integer: 15.0

If you want floating point operations, you need at least one floating point operand!
Hence my giving you two versions: one uses integer math, the other floating point.

Alex Dunlop29-Jul-21 6:48