Coding style II - O(n) checks instead O(1) or doubling code? [modified] - C# Discussion Boards

Re: win32 dll is not working for c# application.

Thomas Krojer5-Jul-11 23:31

5-Jul-11 23:31

if you are running a .net application, build for target "any cpu", the program will start as a 64 bit application - if the machine is running a 64 bit windows.

and if your win32.dll (doesn´t sound like an .net dll) is build for 32 bit (why do i think it is? maybe the 32 in win32.dll?, then it is not possible.

you have to build the .net app explicitly for x86 target. dot.

I cannot remember: What did I before google?

DataGridView Cell Color

Miwin Solutions5-Jul-11 6:31

Miwin Solutions

5-Jul-11 6:31

Hi
I am trying to set the BackColor of a specific cell (C2010 Enterprise), but have failed so far - can you help!

I have tried this:
DataGridView1[2, 3].Style.BackColor = Color.Red;
but that didnt work (doesnt appear to do anything) Cry | :((

Have you any other suggestions?

Cheers

Re: DataGridView Cell Color

Abhinav S5-Jul-11 7:05

Abhinav S

5-Jul-11 7:05

Try setting the DefaultGridViewCellStyle - some code here[^].

The funniest thing about this particular signature is that by the time you realise it doesn't say anything it's too late to stop reading it.

Re: DataGridView Cell Color

GenJerDan5-Jul-11 8:22

GenJerDan

5-Jul-11 8:22

How/Where are you determining which cell and trying to set it?

I usually do things like this to highlight a cell containing a value that is out-of-tolerance or such, i.e. like below 75 or whatever.

private void dataGridView1_RowsAdded(object sender, DataGridViewRowsAddedEventArgs e)
{
  DataGridViewRow R = dataGridView1.Rows[e.RowIndex];
  R.Cells[6].Style.BackColor = Color.Red;
}

Or do it like in the MSDN link in the CellFormatting event, which may be better. Smile | :)

Build a man a fire, and he'll be warm for a day.
Set a man on fire, and he'll be warm for the rest of his life.

My Mu[sic]
My Films
My Windows Programs, etc.

Re: DataGridView Cell Color

Miwin Solutions5-Jul-11 11:59

Miwin Solutions

5-Jul-11 11:59

Thanks for replying!

I have just tried your example, and that was fine. I have now gone back to my original and that seems to be working as well?! I dont know what I was doing before, but all is OK now Smile | :)

Cheers
Mike

Datagridview data entry

bugindia5-Jul-11 2:33

bugindia

5-Jul-11 2:33

Hi,

I am currently doing a project in C#.net. I am using a datagridview for data entry purpose.
The first column is a drop down combox column. After selecting the value from the list, I press Enter key. The cursor is not moving to next cell. It is moving to the next row of the same column. How to make it to move to the next column of the same row. Please help me.

private void frmInward_Load(object sender, EventArgs e)
       {
           txtInwardNo.Text=ReturnInwardNo();
           LoadGridcolumns();
           LoadSuppliers();

       }

       private void LoadGridcolumns()
       {
           string SQL;
           OleDbConnection obcon = new OleDbConnection();

           SQL = "";
           SQL = "select '' as ItemGroup,'' as Item,Qty,Amount from InwardDetails";
           obcon.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "/MsBakery.mdb";
           obcon.Open();
           OleDbDataAdapter obda = new OleDbDataAdapter(SQL, obcon);
           DataSet ds = new DataSet();
           obda.Fill(ds,"InwardDetails");
           dgvInwardDet.DataSource = ds;
           dgvInwardDet.DataMember = "InwardDetails";

           dgvInwardDet.AutoResizeColumns();

       }

       private string ReturnInwardNo()
       {
           string InwardNo;
           InwardNo = "";

           OleDbConnection obcon = new OleDbConnection();
           OleDbCommand obcmd = new OleDbCommand();
           string SQL;
           bool status;

           status = false;

           try
           {
               obcon.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "/MsBakery.mdb";
               obcon.Open();
               SQL = "SELECT TOP 1 InwardNo FROM Inward ORDER BY InwardNo DESC";
               obcmd.CommandText = SQL;
               obcmd.Connection = obcon;

               OleDbDataReader obdr = obcmd.ExecuteReader();
               if (obdr.Read())
               {
                   InwardNo = Convert.ToString(Convert.ToInt32(obdr["InwardNo"].ToString()) + 1);
               }
               else
               {
                  return "1";
               }

           }

           catch (OleDbException ex)
           {
               MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
               status = true;
           }

           finally
           {
               obcon.Close();
               if (!status)
               {
                   obcon = null;
                   obcmd = null;
               }

           }
           return InwardNo;
       }

       private void LoadSuppliers()
       {
           DataGridViewComboBoxColumn dgvcomcol = new DataGridViewComboBoxColumn ();
           //ComboBox cb = new ComboBox();

           dgvcomcol.MaxDropDownItems = 5;
           dgvcomcol.AutoComplete= true;
           //dgvcomcol.AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill;
          // dgvcomcol.FlatStyle = FlatStyle.Flat;
           //dgvcomcol.DisplayMember = "Supplier";
           dgvcomcol.DisplayStyle = DataGridViewComboBoxDisplayStyle.Nothing;
           dgvcomcol.DisplayIndex = 0;
          // dgvcomcol.AutoSizeMode = DataGridViewAutoSizeColumnsMode.Fill ;
           dgvcomcol.HeaderText = "Supplier";
           PrepareSupplierCombo(dgvcomcol);
           //dgvcomcol.AutoSizeMode = DataGridViewAutoSizeColumnsMode.Fill;
           //dgvInwardDet.Columns[0].AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill;
           //dgvcomcol.AutoSizeMode = DataGridViewAutoSizeColumnsMode.Fill;
           dgvInwardDet.Columns.Add(dgvcomcol);
           //dgvcomcol.DropDownWidth
           dgvcomcol.Width = 100;


           //dgvcomcol.AutoSizeMode=;


       }

       private void PrepareSupplierCombo(DataGridViewComboBoxColumn col)
       {

           OleDbConnection obcon = new OleDbConnection();
           string SQL;

           obcon.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "/MsBakery.mdb";
           obcon.Open();
           SQL = "SELECT SupplierName as Supplier,SupplierID  FROM Suppliers";
           OleDbDataAdapter obda = new OleDbDataAdapter(SQL, obcon);
           DataSet ds = new DataSet();
           obda.Fill(ds, "Suppliers");
           col.Items.Clear();
           col.DataSource = ds.Tables[0];
           col.DisplayMember = "Supplier";
           col.ValueMember = "SupplierID";
           //col.AutoSizeMode = DataGridViewAutoSizeColumnsMode.Fill;
           //col.AutoSizeMode = AutoSizeMode.GrowOnly;
           //col.Sorted = true;

       }

       private void dgvInwardDet_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
       {
           //dgvInwardDet_KeyDown += new DataGridViewEditingControlShowingEventHandler (dgvInwardDet_KeyDown);
           ComboBox com = e.Control as ComboBox;
           //ListBox lb = new ListBox();

           com.AutoCompleteMode = AutoCompleteMode.Suggest;
           com.AutoCompleteSource = AutoCompleteSource.ListItems;
           com.FlatStyle = FlatStyle.Flat;


          // com = Convert.ChangeType(e.Control, ComboBox);


           //dgvInwardDet.KeyDown += new KeyEventHandler(dgvInwardDet_KeyDown);
         //  dgvInwardDet.CellLeave -= new DataGridViewCellEventHandler(dgvInwardDet_CellLeave);
          // com.KeyDown += new KeyEventHandler(ComboBox_KeyDown);

       }

With Regards,
Arun V

Re: Datagridview data entry

Carmelo La Monica5-Jul-11 11:04

Carmelo La Monica

5-Jul-11 11:04

Hello bugindia,

if I understand you hitting enter to move to the next cell in the same row, handle the KeyDown event of your datagrid class SystemKeys and force by moving the cursor to the right and subsequently has an example here.

private void dataGridView1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Enter)
    {
        SendKeys.Send("{Right}");
        e.Handled = true;
    }
}

Bye

Coding style II - O(n) checks instead O(1) or doubling code? [modified]

Lutosław5-Jul-11 1:06

Lutosław

5-Jul-11 1:06

What is better:

void AddSharpsAndFlats(StaffVisual staff, Clef clef)
{
    int symbolCount = _context.GetSharpCount();
    if (symbolCount > 0)            
        for (int i = 0; i < symbolCount; i++)
        {
            staff.AddVisual(new SharpVisual
            {
                Position = clef.SharpPostions[(int)MusicContext.SharpOrder[i]]
            });
            staff.AddVisual(PlaceHolderVisual.ThinPlaceholder);
        }            
    else if (symbolCount < 0)            
        for (int i = 0; i < -symbolCount; i++)
        {
            staff.AddVisual(new FlatVisual
            {
                Position = clef.FlatPostions[(int)MusicContext.FlatOrder[i]]
            });
            staff.AddVisual(PlaceHolderVisual.ThinPlaceholder);
        }            
}

OR: move symbolCount < 0 inside a loop (and use abs(symbolCount))? Then I would have a single loop but I would also have n checks. Note: symbolCount is a value in range {-7,...,-1,0,1,...,7}.

EDIT: corrected typo

Thanks and

Greetings - Jacek

modified on Tuesday, July 5, 2011 7:50 AM

Re: Coding style II - O(n) checks instead O(1) or doubling code?

Pete O'Hanlon5-Jul-11 1:21

Pete O'Hanlon

5-Jul-11 1:21

Your logic doesn't work here. You can't have i starting at zero and then being compared to symbolCount when symbolCount is less than zero. The loop won't run.

Forgive your enemies - it messes with their heads

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

Re: Coding style II - O(n) checks instead O(1) or doubling code?

Lutosław5-Jul-11 1:38

Lutosław

5-Jul-11 1:38

t'was a typo which came out while debugging a moment after I have posted this / forgot to correct. It's done now.

Greetings - Jacek

Re: Coding style II - O(n) checks instead O(1) or doubling code?

Pete O'Hanlon5-Jul-11 2:48

Pete O'Hanlon

5-Jul-11 2:48

As these are mutually exclusive conditions, I think that having them as separate loops is a perfectly valid construct. As soon as you add the abs(symbolCount) condition in there, you are introducing something that requires thinking about by somebody reviewing your code. While this isn't, necessarily, a bad thing, consider that if this is a commercial project, then at some point, Nervous Nigel the spotty apprentice coder is going to try to do something with the code and end up breaking it because he doesn't understand it.

The KISS principal applies.

Forgive your enemies - it messes with their heads

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

Re: Coding style II - O(n) checks instead O(1) or doubling code?

kevinnicol5-Jul-11 10:10

kevinnicol

5-Jul-11 10:10

Nervous Nigel has just made its way into my weekly vocabulary. Describes people I often refer to perfectly. Thank you good sir.

Re: Coding style II - O(n) checks instead O(1) or doubling code?

Pete O'Hanlon5-Jul-11 10:15

Pete O'Hanlon

5-Jul-11 10:15

You're welcome - I know several of them.

Forgive your enemies - it messes with their heads

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

Re: Coding style II - O(n) checks instead O(1) or doubling code?

PIEBALDconsult5-Jul-11 3:13

PIEBALDconsult

5-Jul-11 3:13

I dunno. Maybe squeeze the loops into a common method?

if (symbolCount > 0)            
{
    AddSymbols ( SharpFactory , clef.SharpPostions , staff , symbolCount ) ;
}
else if (symbolCount < 0)           
{
    AddSymbols ( FlatFactory , clef.FlatPostions , staff , symbolCount ) ;
}

Just a thought.

Otherwise, leave it the way it is.

Re: Coding style II - O(n) checks instead O(1) or doubling code?

BobJanova5-Jul-11 3:30

BobJanova

5-Jul-11 3:30

The two loops set off my code style alarms. But having reviewed it, and worked out the domain here, it really is two separate operations, and there's not much there that is common enough to pull out. When it comes down to it you're duplicating four lines:

for(int i = 0; i < symbolCount; i++) {
 staff.AddVisual(something);
 staff.AddVisual(PlaceHolderVisual.ThinPlaceholder);
}

So I think I would leave it, but with a note (mental or explicit) to watch this space because if you add more key signature related stuff it could get messy and need refactoring.

Now you could take the duplication out like this:

void AddSharpsAndFlats(StaffVisual staff, Clef clef)
{
  int symbolCount = _context.GetSharpCount();

  if(symbolCount != 0){
    // I guess this is List<Position> or Position[]
    var Positions = symbolCount > 0 ? clef.SharpPositions : clef.FlatPositions;
    var Order = symbol.Count > 0 ? MusicContext.SharpOrder : MusicContext.FlatOrder;
    VisualCreator creator = symbolCount > 0 ? (p => new SharpVisual(p)) : (p => new FlatVisual(p));
    
    symbolCount = symbolCount > 0 ? symbolCount : -symbolCount; // abs for ints
    
    for (int i = 0; i < symbolCount; i++)
    {
      staff.AddVisual(creator( {
        Position = Positions[(int)Order[i]]
      });
      staff.AddVisual(PlaceHolderVisual.ThinPlaceholder);
    }
  }
}

... where

delegate VisualCreator(Position position);

(You could also have a VisualFactory that hides that selection away from you.)

I'm not convinced that for such a small duplication this is worthwhile.

Work with Web cam

Abbath13495-Jul-11 0:31

Abbath1349

5-Jul-11 0:31

Prompt to write a program to work with web camera to as I understand it to use OpenCV? Tell a escho library (preferably C #) to work with web camera and computer vision? and in what language it is better to write C # or C + + Open CV is a library of C + + swoop I know

Re: Work with Web cam

Richard MacCutchan5-Jul-11 6:28

Richard MacCutchan

5-Jul-11 6:28

Some good C# hits here[^].

The best things in life are not things.

Re: Work with Web cam

GuyThiebaut5-Jul-11 10:21

GuyThiebaut

5-Jul-11 10:21

Check out this article Motion Detection Algorithms[^]

It shows you how to integrate a webcam with motion detection.

It was the basis for this TeboCam[^]

One small tip - your question is very brief however computer vision is a hugely complex area - even Microsoft have a long way to go with the Kinect...

Continuous effort - not strength or intelligence - is the key to unlocking our potential.(Winston Churchill)

String value in C#

Pierre besquent5-Jul-11 0:13

Pierre besquent

5-Jul-11 0:13

Hi everyBody;
I want to browse my string like this:

// Extraire la suite de Zero au début du nombre.
			int		   k = 0;
			char	   car = ' ';
			string     successZero = string.Empty;
			char[] arr;
			arr = chaine.ToCharArray(0, chaine.Length);
			if (arr [0] != '0')
			{
				while (k < chaine.Length)
				{   
					car = arr [k];
					if (car == '0')
					{
						successZero += car;
						car	= ' ';
						k ++;
					 }
					 else
						break;
				}
			}
			else
				successZero = "";
			return successZero;

but if I enter "001" the arr [0]= 48 '0' and NOT '0' only
I don't know it appears to me that 48 (I know it is the ASCII of 0)
but I want to discutate sur arr[0] == '0' or not
How to remidiate to that?
ty

Re: String value in C#

Richard MacCutchan5-Jul-11 0:22

Richard MacCutchan

5-Jul-11 0:22

I'm not sure what you are trying to do but your code does not seem to correspond to your description. You are looking for a zero in the arry (maybe), or trying to count them, but the line:

if (arr [0] != '0')

means that you never enter the search loop if the first character of your string is '0', as is the case you describe.

The best things in life are not things.

Re: String value in C#

Pierre besquent5-Jul-11 0:26

Pierre besquent

5-Jul-11 0:26

Hi,
yes that what I search arr [0] appears to me always != '0' even I enter chaine = "001" it appears to me arr [0] = 48 '0'
what can I do?
ty

Re: String value in C#

Rhuros5-Jul-11 0:46

Rhuros

5-Jul-11 0:46

What are you expecting arr[0] to be?

With you input of "001" you can expect your array of characters to be:#

arr[0] = '0'
arr[1] = '0'
arr[2] = '1'

So in this case your code is going to me the condition of (arr[k] != '0') on the 3rd iteration of your loop, not on the first.

Is this what you’re looking for?

Re: String value in C#

Richard MacCutchan5-Jul-11 0:59

Richard MacCutchan

5-Jul-11 0:59

Pierre besquent wrote:
yes that what I search arr [0] appears to me always != '0' even I enter chaine = "001"

No it doesn't; your coding logic is wrong as I stated in my previous answer.

I have a feeling something is still getting lost in translation here, but I cannot figure it out.

The best things in life are not things.

Re: String value in C#

BobJanova5-Jul-11 0:39

BobJanova

5-Jul-11 0:39

This is simply a viewing thing in your IDE. arr[0] will be '0' in this case. The problem is that if arr[0] is '0', the outer if fails, and if it is not '0', the if inside the while will fail on the first iteration and break out of the loop. You have a simple logic problem.

I think the outer if is entirely unnecessary (even if it is corrected).

Re: String value in C#

Pierre besquent5-Jul-11 0:47

Pierre besquent

5-Jul-11 0:47

Hi,
viewing thing in your IDE?what u mean. I debug and I found that arr[0] = 48 '0' even if chaine = "001". I know what i write so this it is my probleme: WHY it considerate arr [0] = 48 '0'??????
ty

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