Re: current state of old issue of Enum boxing when used as Keys in a Dictionary ? - C# Discussion Boards

Re: Issue around converting Expression<Func<T, bool>> to Expression<Func<U, bool>>

Richard Deeming31-Mar-16 4:59

31-Mar-16 4:59

This sort of expression rewriting can get very complicated. Something like this should work for fairly simple expressions:

public sealed class ExpressionParameterModificationVisitor<TFrom, TTo> : ExpressionVisitor
{
    private readonly Stack<Dictionary<ParameterExpression, ParameterExpression>> _parameterMaps = new Stack<Dictionary<ParameterExpression, ParameterExpression>>();
    
    protected override Expression VisitLambda<T>(Expression<T> node)
    {
        var parameters = VisitAndConvert<ParameterExpression>(node.Parameters, "VisitLambda");
        var parameterMap = node.Parameters.Zip(parameters, (source, dest) => new { source, dest }).ToDictionary(p => p.source, p => p.dest);
        _parameterMaps.Push(parameterMap);
        try
        {
            var body = Visit(node.Body);
            return Expression.Lambda(body, parameters);
        }
        finally
        {
            _parameterMaps.Pop();
        }
    }
    
    protected override Expression VisitParameter(ParameterExpression expression)
    {
        if (typeof(TFrom) != expression.Type) return expression;
        return Expression.Parameter(typeof(TTo), expression.Name);
    }
    
    private Expression MapParameter(Expression expression)
    {
        var param = expression as ParameterExpression;
        if (param != null)
        {
            ParameterExpression result;
            if (_parameterMaps.Count != 0 && _parameterMaps.Peek().TryGetValue(param, out result))
            {
                expression = result;
            }
        }
        
        return expression;
    }
    
    protected override Expression VisitMember(MemberExpression node)
    {
        if (typeof(TFrom) != node.Expression.Type) return node.Update(Visit(node.Expression));
        
        var expression = MapParameter(node.Expression);
        var member = typeof(TTo).GetProperty(node.Member.Name);
        return Expression.MakeMemberAccess(expression, member);
    }
    
    public static Expression<Func<TTo, TResult>> Modify<TResult>(Expression<Func<TFrom, TResult>> expression)
    {
        if (expression == null) throw new ArgumentNullException(nameof(expression));
        
        var visitor = new ExpressionParameterModificationVisitor<TFrom, TTo>();
        var result = visitor.Visit(expression);
        return (Expression<Func<TTo, TResult>>)result;
    }
}

NB: You need to maintain a stack of parameter maps to cope with nested lambdas - for example:

foo => foo.SomeCollection.Count(bar => bar.SomeFlag)

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

modified 31-Mar-16 11:48am.

Re: Issue around converting Expression<Func<T, bool>> to Expression<Func<U, bool>>

Sascha Lefèvre31-Mar-16 5:21

Sascha Lefèvre

31-Mar-16 5:21

Just a small kind of typo:

public static Expression<Func<TTo, TResult>> Modify<TResult>(Expression<Func<TFrom, TResult>> expression)
                                                                        ^^^^

Don't tell me you just typed that in Notepad!?

If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson

Re: Issue around converting Expression<Func<T, bool>> to Expression<Func<U, bool>>

Richard Deeming31-Mar-16 5:49

Richard Deeming

31-Mar-16 5:49

LINQPad, but I changed the Modify method as I posted it.

Fixed. Smile | :)

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: Issue around converting Expression<Func<T, bool>> to Expression<Func<U, bool>>

Sascha Lefèvre31-Mar-16 6:41

Sascha Lefèvre

31-Mar-16 6:41

As Richard's solution is working fine there's no practical need for this, but in case you're interested, for the purpose of learning about building Expressions: I answered a same, earlier question with a solution that does this without the use of ExpressionVisitor:
Mapping expressions Expression<Func<UserVM, object>> to Expression<Func<User, object>>[^]

If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson

Using Deployment Item with Directory.GetFiles

RamboSp31-Mar-16 2:17

RamboSp

31-Mar-16 2:17

I'm trying to write a unit test with DeploymentItem attribute and in the code that is being tested I'm using Directory.GetFiles(directoryPath).

I tried to use DeploymentItem attribute to deploy the parent directory and have put directory name in directory path. However, it does not seem to work. Can you please point me out to doing it the proper way?

Thanks in advance.

Re: Using Deployment Item with Directory.GetFiles

Eddy Vluggen1-Apr-16 1:33

Eddy Vluggen

1-Apr-16 1:33

RamboSp wrote:
However, it does not seem to work.

Did it throw an exception? Did it fail silently? Did it refuse to compile?

RamboSp wrote:
Can you please point me out to doing it the proper way?

There's a How to: Deploy Files for Tests[^]-topic on MSDN, and the description of the DeploymentItemAttribute Class (Microsoft.VisualStudio.TestTools.UnitTesting)[^].

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

current state of old issue of Enum boxing when used as Keys in a Dictionary ?

BillWoodruff31-Mar-16 2:15

BillWoodruff

31-Mar-16 2:15

Prior to .NET 4 there was a performance penalty (caused by boxing/unboxing) in using Enums as Keys in a Dictionary [^]; and there were some work-arounds, for example, this CP article: [^].

Comments on .NET 4 indicate the boxing is now not performed when Enum values are of the "simplest Type." I think that means when the values are 'Int rather than the other legal Types, but I am not sure about that.

I have been searching for a definitive statement on Enums and boxing in .NET 4.5 and above, but no luck so far. I wonder if an Enum using Flags would be handled in any different way (I doubt that).

thanks, Bill

«The truth is a snare: you cannot have it, without being caught. You cannot have the truth in such a way that you catch it, but only in such a way that it catches you.» Soren Kierkegaard

Re: current state of old issue of Enum boxing when used as Keys in a Dictionary ?

Richard Deeming31-Mar-16 2:52

Richard Deeming

31-Mar-16 2:52

Looking at the source of the EqualityComparer<T> class[^], there's special-case code to handle enums where the underlying type is Byte, SByte, Int16, UInt16, Int32, UInt32, Int64 or UInt64:

if (t.IsEnum) {
    TypeCode underlyingTypeCode = Type.GetTypeCode(Enum.GetUnderlyingType(t));

    // Depending on the enum type, we need to special case the comparers so that we avoid boxing
    // Note: We have different comparers for Short and SByte because for those types we need to make sure we call GetHashCode on the actual underlying type as the 
    // implementation of GetHashCode is more complex than for the other types.
    switch (underlyingTypeCode) {
        case TypeCode.Int16: // short
            return (EqualityComparer<T>)RuntimeTypeHandle.CreateInstanceForAnotherGenericParameter((RuntimeType)typeof(ShortEnumEqualityComparer<short>), t);
        case TypeCode.SByte:
            return (EqualityComparer<T>)RuntimeTypeHandle.CreateInstanceForAnotherGenericParameter((RuntimeType)typeof(SByteEnumEqualityComparer<sbyte>), t);
        case TypeCode.Int32:
        case TypeCode.UInt32:
        case TypeCode.Byte:
        case TypeCode.UInt16: //ushort
            return (EqualityComparer<T>)RuntimeTypeHandle.CreateInstanceForAnotherGenericParameter((RuntimeType)typeof(EnumEqualityComparer<int>), t);
        case TypeCode.Int64:
        case TypeCode.UInt64:
            return (EqualityComparer<T>)RuntimeTypeHandle.CreateInstanceForAnotherGenericParameter((RuntimeType)typeof(LongEnumEqualityComparer<long>), t);
    }
}

The presence of the [Flags] attribute won't make any difference.

Obviously, this is the latest version of the BCL. I'm not sure how far back this was added.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Message Removed

31-Mar-16 0:25

PomegranateTiger

31-Mar-16 0:25

Message Removed

modified 31-Mar-16 9:18am.

Sync SQLite with Oracle or Postgre

Potestas30-Mar-16 21:42

Potestas

30-Mar-16 21:42

Hello,

i'am using the sync Framework to sync a local sdf with different Server databases (Oracle, Postgre).

Now i have a look for a newer versions or alternative solution.

I am going to use a local sqlite instead of the SQL Compact but i do not find current solutions to sync an sqlite against Oracle or Postgre.

Many Thanks

Re: Sync SQLite with Oracle or Postgre

Nathan Minier31-Mar-16 1:26

Nathan Minier

31-Mar-16 1:26

You can treat them as ODBC data sources and should be able to sync against them that way.

I know this works for Oracle at any rate, providing you have the Oracle client installed on the machine that will provide the data source.

C# Tic Tac Toe "Simulator"

Member 1242680830-Mar-16 11:24

Member 12426808

30-Mar-16 11:24

I'm very sorry if I didn't post my code correctly. I am having trouble with this. The code is working to the directions specifications, but, I am not sure about one thing. How do avoid getting....lets say....6 "O's" and 3 "X's" when I run the program. That is not simulation. Thanks.

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.Windows.Forms;

namespace Tic_Tac_Toe
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            const int ROWS = 3;
            const int COLS = 3;
            int[,] game = new int[ROWS, COLS];

            Random rand = new Random();

            for (int row = 0; row < ROWS; row++)
            {
                for (int col = 0; col < COLS; col++)
                {
                    game[row, col] = rand.Next(2);
                }
                if (game[0, 0] == 0)
                {
                    label2.Text = "O";
                }
                else
                {
                    label2.Text = "X";
                }
                if (game[0, 1] == 0)
                {
                    label3.Text = "O";
                }
                else
                {
                    label3.Text = "X";
                }
                if (game[0, 2] == 0)
                {
                    label4.Text = "O";
                }
                else
                {
                    label4.Text = "X";
                }
                if (game[1, 0] == 0)
                {
                    label5.Text = "O";
                }
                else
                {
                    label5.Text = "X";
                }
                if (game[1, 1] == 0)
                {
                    label6.Text = "O";
                }
                else
                {
                    label6.Text = "X";
                }
                if (game[1, 2] == 0)
                {
                    label7.Text = "O";
                }
                else
                {
                    label7.Text = "X";
                }
                if (game[2, 0] == 0)
                {
                    label8.Text = "O";
                }
                else
                {
                    label8.Text = "X";
                }
                if (game[2, 1] == 0)
                {
                    label9.Text = "O";
                }
                else
                {
                    label9.Text = "X";
                }
                if (game[2, 2] == 0)
                {
                    label10.Text = "O";
                }
                else
                {
                    label10.Text = "X";
                }

                if (game[0, 0] == 0 && game[0, 1] == 0 && game[0, 2] == 0)
                {
                    label11.Text = "O Wins";
                }
                 else if (game[0, 0] == 1 && game[0, 1] == 1 && game[0, 2] == 1)
                    {
                        label11.Text = "X Wins";
                    }
                else if (game[1, 0] == 0 && game[1, 1] == 0 && game[1, 2] == 0)
                {
                    label11.Text = "O Wins";
                }
                else if (game[1, 0] == 1 && game[1, 1] == 1 && game[1, 2] == 1)
                {
                    label11.Text = "X Wins";
                }
                else if (game[2, 0] == 0 && game[2, 1] == 0 && game[2, 2] == 0)
                {
                    label11.Text = "O Wins";
                }
                else if (game[2, 0] == 1 && game[2, 1] == 1 && game[2, 2] == 1)
                {
                    label11.Text = "X Wins";
                }
                else if (game[0, 0] == 0 && game[1, 0] == 0 && game[2, 0] == 0)
                {
                    label11.Text = "O Wins";
                }
                else if (game[0, 0] == 1 && game[1, 0] == 1 && game[2, 0] == 1)
                {
                    label11.Text = "X Wins";
                }
                else if (game[0, 1] == 0 && game[1, 1] == 0 && game[2, 1] == 0)
                {
                    label11.Text = "O Wins";
                }
                else if (game[0, 1] == 1 && game[1, 1] == 1 && game[2, 1] == 1)
                {
                    label11.Text = "X Wins";
                }
                else if (game[0, 2] == 0 && game[1, 2] == 0 && game[2, 2] == 0)
                {
                    label11.Text = "O Wins";
                }
                else if (game[0, 2] == 1 && game[1, 2] == 1 && game[2, 2] == 1)
                {
                    label11.Text = "X Wins";
                }
                else if (game[0, 0] == 0 && game[1, 1] == 0 && game[2, 2] == 0)
                {
                    label11.Text = "O Wins";
                }
                else if (game[0, 0] == 1 && game[1, 1] == 1 && game[2, 2] == 1)
                {
                    label11.Text = "X Wins";
                }
                else if (game[0, 2] == 0 && game[1, 1] == 0 && game[2, 0] == 0)
                {
                    label11.Text = "O Wins";
                }
                else if (game[0, 2] == 1 && game[1, 1] == 1 && game[2, 0] == 1)
                {
                    label11.Text = "X Wins";
                }
                else
                {
                    label11.Text = "DRAW";
                }


                


                }

            }
        }
    }

Re: C# Tic Tac Toe "Simulator"

Sascha Lefèvre30-Mar-16 17:15

Sascha Lefèvre

30-Mar-16 17:15

The problem is that there's no context for the random values generation. You generate each 0 or 1 irrespective of how many there already are. So you need a method that ensures that there are either four 0's and five 1's or the other way around. There are several ways to do that. Here are two:

a) Create a one-dimensional array with a length of nine and fill it either with four or five 1's (the other indices are 0 by default and to decide whether it will be four or five 1's you can use Random.Next(4, 6) ). Then randomly swap the values of two indices multiple times. Then fill the values from that one-dimensional array into your two-dimensional game[3,3]-array.

b) Create an array of nine random numbers with no explicit upper bound (so the maximum value will be Int32.MaxValue). For the first four or five of those numbers, set the least significant bit (LSB) to 0 and for the remaining values, set it to 1. Then sort the array by values. Then fill the two-dimensional game-array based on the values from the sorted array but take only the value of the LSB.

There's something more to say about your code but, as I have to finish, I'll do that later if nobody else did until then.

If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson

Re: C# Tic Tac Toe "Simulator"

Rob Philpott30-Mar-16 23:41

Rob Philpott

30-Mar-16 23:41

Quite interesting code, I can see a fair bit wrong with it.

But, to your question of getting an equal balance of Xs and Os, why don't you just do it the way it's done, but taking it in turns?

That means choosing a random place to put you X or O (flip-flopped), rather than choosing a random X or O to put in an ordered place.

Regards,
Rob Philpott.

Re: C# Tic Tac Toe "Simulator"

Patrice T31-Mar-16 0:55

Patrice T

31-Mar-16 0:55

You can greatly simplify your code by storing "X" and "O" directly in game after changing it to a table of chars.

Patrice

“Everything should be made as simple as possible, but no simpler.” Albert Einstein

REPOST

Richard Deeming31-Mar-16 1:42

Richard Deeming

31-Mar-16 1:42

You have already posted this question in QA:
When creating a tic tac toe "simulator", what do I need to do to make sure that I am getting a realistic number of X's and O's?[^]

Posting the same question multiple times duplicates work and annoys people.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Dynamically close DB2 CLP window using C#

Tej_dev30-Mar-16 6:44

Tej_dev

30-Mar-16 6:44

Hi All,
I have created console application to execute DB2 commands using C#. my commands executed fine and DB2 CLP command window opened i can see output as well. but once my command executed I am not able to close DB2 CLP window using C# code.
I tried to kill Process.GetProcessByName but not succeeded.
I also used Application.Exit() method.
Note: i am connecting to server DB2 using local machine.
Below is my code.

try
           {
 ProcessStartInfo objProcStartInfo;
            Process objProcess;
               //Connect To IBM DB2 database using CLP Process Object
               objProcStartInfo = new ProcessStartInfo("db2cmd.exe", "db2 connect to " + strMasterdatabaseName + " user " + strserviceAccountUserName + " using " + strserviceAccountPassword + "&db2 -f " + strexportFilePath + " > " + strexportLogFilePath + "");
               objProcStartInfo.RedirectStandardOutput = false;
               objProcStartInfo.UseShellExecute = false;
               objProcStartInfo.CreateNoWindow = false;
               objProcess = new Process();
               objProcess.StartInfo = objProcStartInfo;
               objProcess.Start();

           }
           catch (Exception ex)
           {
               Console.WriteLine(ex.ToString());
           }

can someone please provide any direction on this?
Thanks

modified 30-Mar-16 12:49pm.

Message Closed

30-Mar-16 7:19

Gerry Schmitz

30-Mar-16 7:19

Message Closed

modified 30-Mar-16 15:05pm.

Re: Dynamically close DB2 CLP window using C#

Tej_dev30-Mar-16 8:14

Tej_dev

30-Mar-16 8:14

tried below code still DB2 CLP window remains open

using (objProcess = new Process())
{
try
{
//Connect To IBM DB2 database using CLP Process Object
//<tbd> Need to work on autoclose DB2 CLP
objProcStartInfo = new ProcessStartInfo("db2cmd.exe", "db2 connect to " + strMasterdatabaseName + " user " + strserviceAccountUserName + " using " + strserviceAccountPassword + "&db2 -f " + strexportFilePath + " > " + strexportLogFilePath + "");
objProcStartInfo.RedirectStandardOutput = false;
objProcStartInfo.UseShellExecute = false;
objProcStartInfo.CreateNoWindow = false;

objProcess.StartInfo = objProcStartInfo;
objProcess.Start();
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
finally
{
objProcStartInfo = null;
objProcess.Dispose();
}
}
}

Re: Dynamically close DB2 CLP window using C#

Richard Deeming30-Mar-16 8:44

Richard Deeming

30-Mar-16 8:44

Calling Dispose on a Process only cleans up the unmanaged resources; it doesn't terminate the process.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Message Closed

30-Mar-16 8:52

Gerry Schmitz

30-Mar-16 8:52

Message Closed

modified 30-Mar-16 15:05pm.

Re: Dynamically close DB2 CLP window using C#

Richard Deeming30-Mar-16 8:54

Richard Deeming

30-Mar-16 8:54

The window the the OP is seeing belongs to the external db2cmd.exe process. Your answer implied that disposing of the Process instance would close that window.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: Dynamically close DB2 CLP window using C#

Richard Deeming30-Mar-16 8:52

Richard Deeming

30-Mar-16 8:52

Try adding -c at the start of the arguments:

objProcStartInfo = new ProcessStartInfo("db2cmd.exe", string.Format("-c db2 connect to {0} user {1} using {2}&db2 -f {3} > {4}", strMasterdatabaseName, strserviceAccountUserName, strserviceAccountPassword, strexportFilePath, strexportLogFilePath));

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: Dynamically close DB2 CLP window using C#

Tej_dev30-Mar-16 9:03

Tej_dev

30-Mar-16 9:03

excellent , I added -c and its working fine. thanks Richard Smile | :)

objProcStartInfo = new ProcessStartInfo("db2cmd.exe", "-c db2 connect to " + strMasterdatabaseName + " user " + strserviceAccountUserName + " using " + strserviceAccountPassword + "&db2 -f " + strexportFilePath + " > " + strexportLogFilePath + "");

Bitmap to BitmapImage Conversion Not Working - WPF

AmbiguousName30-Mar-16 4:36

AmbiguousName

30-Mar-16 4:36

Hello. I am using following code to convert bitmap to BitmapImage, in order to show on System.Windows.Control.Image control.

  public BitmapImage ConvertBitmapToBitmapImage(System.Drawing.Bitmap bitmap)
  {
      BitmapImage bitmapImage = null;
      using (var memory = new System.IO.MemoryStream())
      {
          bitmap.Save(memory, System.Drawing.Imaging.ImageFormat.Bmp);
          memory.Position = 0;

          bitmapImage = new BitmapImage();
          bitmapImage.BeginInit();
          bitmapImage.StreamSource = memory;
          bitmapImage.EndInit();

          return bitmapImage;
      }
  }

public void ShowPicture(Bitmap bmp)
{
     pictureBox.Source = ConvertBitmapToBitmapImage(bmp);
     return;
}

It does not throw any exception but it does not show picture as well. When I try to view the picture, it opens up WPF visualizer and shows me some values (properties of BitmapImage), while the bitmap is fine.

What is wrong with my code. Thanks for any input.

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