How to print 2 sequential values from array (from datagridview) per page in C#

Question

1.50/5 (2 votes)

See more:

I have a datagridview and foreach CHECKED row it prints the value of a checked row in a page ,if I check 10 rows , the software generates 1 document with 10 pages one to each row. now the software prints one row per page But I need to print TWO ROWS per PAGE how can handle this? part of the code below...

C#

var allCheckedRows = this.dgv1.Rows.Cast<DataGridViewRow>()
                              .Where(row => (bool?)row.Cells[0].Value == true)
                              .ToList();

            if (allCheckedRows.Count > currentPrintingRowIndex)
            {
                var builder = new StringBuilder();

                var currentCheckedRow = allCheckedRows[currentPrintingRowIndex];

                var cellValues = currentCheckedRow.Cells.Cast<DataGridViewCell>()
                        .Where(cell => cell.ColumnIndex > 0)
                        .Select(cell => string.Format("{0}", cell.Value))
                        .ToArray();

                builder.Append(string.Join(",", cellValues));


                string ldp = builder.ToString();
                string[] everyhow = ldp.Split(',');

============================================================
//Current code is

C#

private int currentPrintingIndex = 0;

List<string>CheckedValues = new List<string>();

private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
        {

 var CheckedValues = this.dgv1.Rows.Cast<DataGridViewRow>()
              .Where(row => (bool?)row.Cells[0].Value == true)
              .ToList();

 if (CheckedValues.Count > currentPrintingIndex)
              {
                 var currentValue = CheckedValues[currentPrintingIndex];


                 e.Graphics.DrawString(currentValue.ToString(), fdiag, Brushes.Black, 10, 10);



                 currentPrintingIndex += 1;
             }

 if (CheckedValues.Count > currentPrintingIndex)
             {
                var currentValue = CheckedValues[currentPrintingIndex];



                e.Graphics.DrawString(currentValue.ToString(), fdiag, Brushes.Black, 160, 10);


               currentPrintingIndex += 1;
             }

              e.HasMorePages = CheckedValues.Count > currentPrintingIndex;

}

Thanks in Advance!

Posted 28-Sep-15 9:37am

JoaniSilva

Updated 2-Oct-15 7:06am

v4

Add a Solution

Comments

Sergey Alexandrovich Kryukov 28-Sep-15 16:18pm

What's the difference, one or two rows? Write any number of rows you want? What's the problem?
—SA

JoaniSilva 28-Sep-15 16:48pm

the difference is that now the printing is just a single row per document for exemple: into an array I have 3 rows like row1 value = 000001, row2 value =000002 and row3 value = 000003 and I need to print Row1 and Row2 in the same Document and Row3 in the NEXT Document. I really need Two Rows per Document, if I have 40 Rows I will need to print in 20 Documents!...the sequence is 000001 and 000002 in a document1 and 00003 plus 000004 in the Document2! thanks in advance!!!!

2 solutions

Solution 1

a quick sketch for one possible strategy: (not tested/working code !)

C#

public void ProcessCheckedRows(DataGridView dgv1)
{
    // code by OP
    var allCheckedRows = dgv1.Rows
         .Cast<datagridviewrow>()
         .Where(row => (bool?)row.Cells[0].Value == true)
         .ToList();
    
    StringBuilder builder = new StringBuilder();
    
    for(int i = 0, i < allCheckedRows.Count - 1; i += 2)
    {
       builder.Clear();
      
       builder.Append(ProcessRow(allCheckedRows[i]));
       builder.Append(ProcessRow(allCheckedRows[i + 1]));
    
       PrintDocument(builder);   
    }
    
    // handle a last single row
    if(allCheckedRows % 2 == 1)
    {
       builder.Clear();
       builder.Append(ProcessRow(allCheckedRows.Last()));
       PrintDocument(builder); 
    }
}

public string ProcessRow(DataGridViewRow row)
{
   // row => string
}

public void PrintDocument(StringBuilder sb)
{
   // print
}

Posted 28-Sep-15 11:03am

BillWoodruff

Updated 28-Sep-15 13:08pm

v6

Comments

BillWoodruff 28-Sep-15 19:09pm

Thanks for the assist, Matt ! I simply forgot to increment the for-loop counter by #2 instead of #1 :)

Maciej Los 29-Sep-15 12:40pm

5ed!

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Matt T Heffron · Accepted Answer · 2015-09-28T13:48:00

Solution 2

A variation on BillWoodruff's solution that allows generalization to an arbitrary number of "rows" per "Document" and works with the lazy behavior of IEnumerable<T>:

C#

public void ProcessCheckedRows(DataGridView dgv1)
{
    // code by OP
    var allCheckedRows = dgv1.Rows
         .Cast<DataGridViewRow>()
         .Where(row => (bool?)row.Cells[0].Value == true);
    
    StringBuilder builder = new StringBuilder();
    
    const int RowsPerDocument = 2;
    int rowCount = 0;
    foreach (var row in allCheckedRows)
    {
       builder.Append(ProcessRow(row));
       if (++rowCount == RowsPerDocument)
       {
          PrintDocument(builder);
          builder.Clear();
          rowCount = 0;
       }
    }
    
    // handle possible last document with less than RowsPerDocument rows
    if (rowCount > 0)
    {
       PrintDocument(builder); 
    }
}

Side note: The .Where() looks like it could throw an exception if the Value is null. There's no check for .HasValue!
Perhaps, what is wanted is:

C#

var allCheckedRows = dgv1.Rows .Cast<DataGridViewRow>() .Where(row => ((bool?)row.Cells[0]).GetValueOrDefault(false)); // or .GetValueOrDefault(true) depending on how null should behave... // comparison with true is unnecessary, the value at this point is already bool
Nevermind the Side note!
=================================================
Edit: MTH based on your updated code above, try something like:

C#

private int currentPrintingIndex = 0;
 
List<string>CheckedValues = new List<string>();
 
private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
 
 IEnumerable<DataGridViewRow> CheckedValues = this.dgv1.Rows.Cast<DataGridViewRow>()
              .Where(row => (bool?)row.Cells[0].Value == true)
              .Skip(currentPrintingIndex);
 IEnumerator<DataGridViewRow> cve = CheckedValues.GetEnumerator();
 int count = 0;
 int pos = 10;
 while ((e.HasMorePages = cve.MoveNext()) && count++ < 2)
 {
   var cellValues = cve.Current.Cells.Cast<DataGridViewCell>()
                    .Skip(1)    //instead of .Where(cell => cell.ColumnIndex > 0)
                    .Select(cell => cell.Value.ToString())
                    .ToArray();
   // at .NET 4, string.Join can take IEnumerable<string> so the .ToArray() would be unnecessary
   e.Graphics.DrawString(string.Join(",", cellValues), fdiag, Brushes.Black, pos, 10);
 
   currentPrintingIndex += 1;
   pos += 150;
 }
}

Posted 28-Sep-15 13:48pm

Matt T Heffron

Updated 2-Oct-15 8:25am

v4

Comments

BillWoodruff 28-Sep-15 20:49pm

Your solution gets my 5 !

Hi Matt, this is code I typically use for "chunking" a List into an IEnumerable of IEnumerables inclusive of any "remainder" items left less than the chunk-size:

public IEnumerable<IEnumerable<T>> EatWhile<T>(IEnumerable<T> list, int bitesize)
{
     while (list.Any())
      {
         yield return list.Take(bitesize);
         list = list.Skip(bitesize);
      }

      if (list.Any()) yield return list;
}

There are probably better ways to do this :)

Matt T Heffron 28-Sep-15 20:56pm

This is incredibly inefficient!!!
See my article: Considerations on Efficient use of LINQ Extension Methods

BillWoodruff 28-Sep-15 20:57pm

Okay, I will study your article ! fyi: my preference is to just use straight ahead for-loop processing, but I posted that example because I thought that's what you were trying to do in you solution.

Matt T Heffron 28-Sep-15 21:28pm

I was just "generalizing" your solution.
It could get kind of ugly if OP wanted 20 rows per document (or a parameter to set the number of rows/document)!
Of course, then an inner loop could be used, but it isn't really necessary! But those still need to know how many are actually being processed. My solution doesn't.

BillWoodruff 28-Sep-15 21:37pm

I think the more fun we have the better off the OP :)

cheers, Bill

Maciej Los 29-Sep-15 12:40pm

5ed!

JoaniSilva 2-Oct-15 10:23am

Guys I tried this Two codes lot of times to adapt them to mine but I didn't successed!
the main scenery is to print the first and second CHECKED row in a page and the NEXT 2 rows in other page till the end, if there's 20 checked rows it will be printed in 10 pages the nearest upshot I got was to print the Row index!

Matt T Heffron 2-Oct-15 12:39pm

So, in the debugger, what does allCheckedRows contain?
Does it have the correct contents?
It should be the DataGridViewRow objects for each of the checked rows.
Once you have these objects, it is up to you to convert them to the strings you want to be assembled into the documents.

If you want to show us your current code, use the "Improve question" above, and put the new code below what you originally showed. (A delimiting line ==================================== wouldn't hurt...)

JoaniSilva 2-Oct-15 12:50pm

allCheckedRows contains all the rows that were checked in the datagridview
this rows is divided by 3 columns being "number","description","Price".
being 000001,description,U$ 100,00, 000002,description,U$ 100,00,, 000003,description,U$ 100,00,
whats really changes is the numbers of the first column index 0 in a page 1 must be printed the 000001 and 0000002 but all I got is the Row.index

Matt T Heffron 2-Oct-15 13:24pm

So, what are you doing that corresponds to the: ProcessRow(row)
If you have the row objects but aren't getting the string you want, this is where you need to look.

Matt T Heffron 2-Oct-15 13:40pm

OK, I looked above and saw your new code:
var currentValue = CheckedValues[currentPrintingIndex];
should get the DataGridViewRow object at currentPrintingIndex.
Is there any reason to believe that:
currentValue.ToString()
will return a string with the data from the row, formatted in the way you want?
You should generate this string yourself (like you were doing in the original code!)
You can then verify that it contains what you want it to contain.
The structure of this code is QUITE different from what you started with.

JoaniSilva 2-Oct-15 13:44pm

then this ProcessRow I didn't work out how it will work.

Matt T Heffron 2-Oct-15 14:25pm

I updated the solution.

JoaniSilva 4-Oct-15 13:24pm

I'm Thoroughly Thankful for your help, your help saved me and my Work! I used only an aditional array in order to get the numbers from the cellvalues and split them by a comma! and encrypt each one of them using a Code128 Barcode Library! Bests Regards and Success!!!

Matt T Heffron 5-Oct-15 11:46am

You're welcome.