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I want print the file from the data grid view. But, once I click the Print Preview, the error appear and says: Object reference not set to an instance of an object. Here is the error coming from:

arrColumnLefts.Clear();

in:

void printDocument1_BeginPrint(object sender, PrintEventArgs e)
        {
            try
            {
                strFormat = new StringFormat();
                strFormat.Alignment = StringAlignment.Center;
                strFormat.LineAlignment = StringAlignment.Center;
                strFormat.Trimming = StringTrimming.EllipsisCharacter;

                arrColumnLefts.Clear();
                arrColumnWidths.Clear();
                iCellHeight = 0;
                iRow = 0;
                bFirstPage = true;
                bNewPage = true;

                iTotalWidth = 0;

                foreach (DataGridViewColumn dgvGridCol in dataGridView1.Columns)
                {
                    iTotalWidth += dgvGridCol.Width;
                }
            }

            catch (Exception ex)
            {
                SystemManager.ShowMessageBox("Message: " + ex.Message, "Error", 1);
            }
        }

and:

arrColumnLefts.Add(iLeftMargin);

foreach (DataGridViewColumn GridCol in dataGridView1.Columns)
                            {
                                e.Graphics.FillRectangle(new SolidBrush(Color.Aqua), new Rectangle((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iHeaderHeight));

                                e.Graphics.DrawRectangle(Pens.Black, new Rectangle((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iHeaderHeight));

                                e.Graphics.DrawString(GridCol.HeaderText, GridCol.InheritedStyle.Font, new SolidBrush(GridCol.InheritedStyle.ForeColor), new RectangleF((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iHeaderHeight), strFormat);

                                iCount++;
                            }

foreach (DataGridViewCell Cel in GridRow.Cells)
                        {
                            if (Cel.Value != null)
                            {
                                e.Graphics.DrawString(Cel.Value.ToString(), Cel.InheritedStyle.Font, new SolidBrush(Cel.InheritedStyle.ForeColor = System.Drawing.Color.Blue), new RectangleF((int)arrColumnLefts[iCount], (float)iTopMargin, (int)arrColumnWidths[iCount], (float)iCellHeight), strFormat);

                                //Drawing Cells Borders 
                                e.Graphics.DrawRectangle(Pens.Red, new Rectangle((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iCellHeight));

                                iCount++;
                            }
                        }

in:

void printDocument1_PrintPage(object sender, PrintPageEventArgs e)
        {
            try
            {
                //Set the left margin
                int iLeftMargin = e.MarginBounds.Left, iTopMargin = e.MarginBounds.Top, iTmpWidth = 0;

                //Whether more pages have to print or not
                bool bMorePagesToPrint = false;

                //For the first page to print set the cell width and header height
                if (bFirstPage)
                {
                    foreach (DataGridViewColumn GridCol in dataGridView1.Columns)
                    {
                        iTmpWidth = (int)(Math.Floor((double)((double)GridCol.Width / (double)iTotalWidth * (double)iTotalWidth * ((double)e.MarginBounds.Width / (double)iTotalWidth))));

                        iHeaderHeight = (int)(e.Graphics.MeasureString(GridCol.HeaderText, GridCol.InheritedStyle.Font, iTmpWidth).Height) + 11;

                        // Save width and height of headres
                        arrColumnLefts.Add(iLeftMargin);
                        arrColumnWidths.Add(iTmpWidth);
                        iLeftMargin += iTmpWidth;
                    }
                }

                //Loop till all the grid rows not get printed
                while (iRow < dataGridView1.Rows.Count)
                {
                    DataGridViewRow GridRow = dataGridView1.Rows[iRow];

                    //Set the cell height
                    iCellHeight = GridRow.Height + 5;

                    int iCount = 0;

                    //Check whether the current page settings allo more rows to print
                    if (iTopMargin + iCellHeight >= e.MarginBounds.Height + e.MarginBounds.Top)
                    {
                        bNewPage = true;
                        bFirstPage = false;
                        bMorePagesToPrint = true;
                        break;
                    }

                    else
                    {
                        if (bNewPage)
                        {
                            //Draw Header
                            e.Graphics.DrawString("Database Summary", new Font(dataGridView1.Font, FontStyle.Bold), Brushes.Black, e.MarginBounds.Left, e.MarginBounds.Top - e.Graphics.MeasureString("Database Summary", new Font(dataGridView1.Font, FontStyle.Bold), e.MarginBounds.Width).Height - 13);

                            String strDate = this.textBox4.Text;

                            //Draw Date
                            e.Graphics.DrawString(strDate, new Font(dataGridView1.Font, FontStyle.Regular), Brushes.Black, e.MarginBounds.Left + (e.MarginBounds.Width - e.Graphics.MeasureString(strDate, new Font(dataGridView1.Font, FontStyle.Regular), e.MarginBounds.Width).Width), e.MarginBounds.Top - e.Graphics.MeasureString("Database Summary", new Font(new Font(dataGridView1.Font, FontStyle.Regular), FontStyle.Regular), e.MarginBounds.Width).Height - 13);

                            //Draw Image
                            e.Graphics.DrawImage(pictureBox1.Image, new Rectangle((_screen.Width / 3) - 50, 0, this.pictureBox1.Size.Width, this.pictureBox1.Size.Height));

                            //Draw Columns    
                            iTopMargin = e.MarginBounds.Top;

                            foreach (DataGridViewColumn GridCol in dataGridView1.Columns)
                            {
                                e.Graphics.FillRectangle(new SolidBrush(Color.Aqua), new Rectangle((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iHeaderHeight));

                                e.Graphics.DrawRectangle(Pens.Black, new Rectangle((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iHeaderHeight));

                                e.Graphics.DrawString(GridCol.HeaderText, GridCol.InheritedStyle.Font, new SolidBrush(GridCol.InheritedStyle.ForeColor), new RectangleF((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iHeaderHeight), strFormat);

                                iCount++;
                            }

                            bNewPage = false;
                            iTopMargin += iHeaderHeight;
                        }

                        iCount = 0;

                        //Draw Columns Contents                
                        foreach (DataGridViewCell Cel in GridRow.Cells)
                        {
                            if (Cel.Value != null)
                            {
                                e.Graphics.DrawString(Cel.Value.ToString(), Cel.InheritedStyle.Font, new SolidBrush(Cel.InheritedStyle.ForeColor = System.Drawing.Color.Blue), new RectangleF((int)arrColumnLefts[iCount], (float)iTopMargin, (int)arrColumnWidths[iCount], (float)iCellHeight), strFormat);

                                //Drawing Cells Borders 
                                e.Graphics.DrawRectangle(Pens.Red, new Rectangle((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iCellHeight));

                                iCount++;
                            }
                        }
                    }

                    iRow++;
                    iTopMargin += iCellHeight;
                }

                //If more lines exist, print another page.
                if (bMorePagesToPrint)
                {
                    e.HasMorePages = true;
                }

                else
                {
                    e.HasMorePages = false;
                }
            }

            catch (Exception exc)
            {
                SystemManager.ShowMessageBox("Message: " + exc.Message, "Error", 1);
            }
        }

Here is the full code for print the file:

int iCellHeight, iTotalWidth, iRow, iHeaderHeight = 0;

bool bFirstPage, bNewPage = false;

ArrayList arrColumnLefts, arrColumnWidths = new ArrayList();

void PrintPreview(object sender, EventArgs e)
        {
            PrintPreviewDialog printPreviewDialog = new PrintPreviewDialog();

            printDocument1.DefaultPageSettings.Landscape = true;
            printPreviewDialog.Document = printDocument1;
            ((Form)printPreviewDialog).WindowState = FormWindowState.Maximized;
            printPreviewDialog.ShowDialog();
        }

        void PrintFile(object sender, EventArgs e)
        {
            PrintDialog printDialog = new PrintDialog();

            printDocument1.DefaultPageSettings.Landscape = true;
            printDialog.Document = printDocument1;
            printDialog.UseEXDialog = true;

            if (DialogResult.OK == printDialog.ShowDialog())
            {
                printDocument1.DocumentName = "Document Page Print";
                printDocument1.Print();
            }
        }

        void printDocument1_BeginPrint(object sender, PrintEventArgs e)
        {
            try
            {
                strFormat = new StringFormat();
                strFormat.Alignment = StringAlignment.Center;
                strFormat.LineAlignment = StringAlignment.Center;
                strFormat.Trimming = StringTrimming.EllipsisCharacter;

                arrColumnLefts.Clear();
                arrColumnWidths.Clear();
                iCellHeight = 0;
                iRow = 0;
                bFirstPage = true;
                bNewPage = true;

                iTotalWidth = 0;

                foreach (DataGridViewColumn dgvGridCol in dataGridView1.Columns)
                {
                    iTotalWidth += dgvGridCol.Width;
                }
            }

            catch (Exception ex)
            {
                SystemManager.ShowMessageBox("Message: " + ex.Message, "Error", 1);
            }
        }

        void printDocument1_PrintPage(object sender, PrintPageEventArgs e)
        {
            try
            {
                //Set the left margin
                int iLeftMargin = e.MarginBounds.Left, iTopMargin = e.MarginBounds.Top, iTmpWidth = 0;

                //Whether more pages have to print or not
                bool bMorePagesToPrint = false;

                //For the first page to print set the cell width and header height
                if (bFirstPage)
                {
                    foreach (DataGridViewColumn GridCol in dataGridView1.Columns)
                    {
                        iTmpWidth = (int)(Math.Floor((double)((double)GridCol.Width / (double)iTotalWidth * (double)iTotalWidth * ((double)e.MarginBounds.Width / (double)iTotalWidth))));

                        iHeaderHeight = (int)(e.Graphics.MeasureString(GridCol.HeaderText, GridCol.InheritedStyle.Font, iTmpWidth).Height) + 11;

                        // Save width and height of headres
                        arrColumnLefts.Add(iLeftMargin);
                        arrColumnWidths.Add(iTmpWidth);
                        iLeftMargin += iTmpWidth;
                    }
                }

                //Loop till all the grid rows not get printed
                while (iRow < dataGridView1.Rows.Count)
                {
                    DataGridViewRow GridRow = dataGridView1.Rows[iRow];

                    //Set the cell height
                    iCellHeight = GridRow.Height + 5;

                    int iCount = 0;

                    //Check whether the current page settings allo more rows to print
                    if (iTopMargin + iCellHeight >= e.MarginBounds.Height + e.MarginBounds.Top)
                    {
                        bNewPage = true;
                        bFirstPage = false;
                        bMorePagesToPrint = true;
                        break;
                    }

                    else
                    {
                        if (bNewPage)
                        {
                            //Draw Header
                            e.Graphics.DrawString("Database Summary", new Font(dataGridView1.Font, FontStyle.Bold), Brushes.Black, e.MarginBounds.Left, e.MarginBounds.Top - e.Graphics.MeasureString("Database Summary", new Font(dataGridView1.Font, FontStyle.Bold), e.MarginBounds.Width).Height - 13);

                            String strDate = this.textBox4.Text;

                            //Draw Date
                            e.Graphics.DrawString(strDate, new Font(dataGridView1.Font, FontStyle.Regular), Brushes.Black, e.MarginBounds.Left + (e.MarginBounds.Width - e.Graphics.MeasureString(strDate, new Font(dataGridView1.Font, FontStyle.Regular), e.MarginBounds.Width).Width), e.MarginBounds.Top - e.Graphics.MeasureString("Database Summary", new Font(new Font(dataGridView1.Font, FontStyle.Regular), FontStyle.Regular), e.MarginBounds.Width).Height - 13);

                            //Draw Image
                            e.Graphics.DrawImage(pictureBox1.Image, new Rectangle((_screen.Width / 3) - 50, 0, this.pictureBox1.Size.Width, this.pictureBox1.Size.Height));

                            //Draw Columns    
                            iTopMargin = e.MarginBounds.Top;

                            foreach (DataGridViewColumn GridCol in dataGridView1.Columns)
                            {
                                e.Graphics.FillRectangle(new SolidBrush(Color.Aqua), new Rectangle((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iHeaderHeight));

                                e.Graphics.DrawRectangle(Pens.Black, new Rectangle((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iHeaderHeight));

                                e.Graphics.DrawString(GridCol.HeaderText, GridCol.InheritedStyle.Font, new SolidBrush(GridCol.InheritedStyle.ForeColor), new RectangleF((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iHeaderHeight), strFormat);

                                iCount++;
                            }

                            bNewPage = false;
                            iTopMargin += iHeaderHeight;
                        }

                        iCount = 0;

                        //Draw Columns Contents                
                        foreach (DataGridViewCell Cel in GridRow.Cells)
                        {
                            if (Cel.Value != null)
                            {
                                e.Graphics.DrawString(Cel.Value.ToString(), Cel.InheritedStyle.Font, new SolidBrush(Cel.InheritedStyle.ForeColor = System.Drawing.Color.Blue), new RectangleF((int)arrColumnLefts[iCount], (float)iTopMargin, (int)arrColumnWidths[iCount], (float)iCellHeight), strFormat);

                                //Drawing Cells Borders 
                                e.Graphics.DrawRectangle(Pens.Red, new Rectangle((int)arrColumnLefts[iCount], iTopMargin, (int)arrColumnWidths[iCount], iCellHeight));

                                iCount++;
                            }
                        }
                    }

                    iRow++;
                    iTopMargin += iCellHeight;
                }

                //If more lines exist, print another page.
                if (bMorePagesToPrint)
                {
                    e.HasMorePages = true;
                }

                else
                {
                    e.HasMorePages = false;
                }
            }

            catch (Exception exc)
            {
                SystemManager.ShowMessageBox("Message: " + exc.Message, "Error", 1);
            }
        }

Thank you guys!

Your answer much appreciated!

Unknown User
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2 Answers2

3

chanage 

ArrayList arrColumnLefts, arrColumnWidths = new ArrayList();

to 

ArrayList arrColumnLefts = new ArrayList();
ArrayList arrColumnWidths  = new ArrayList();

OR

ArrayList arrColumnLefts = new ArrayList(), arrColumnWidths  = new ArrayList();

UPDATE:

ArrayList arrColumnLefts, arrColumnWidths = new ArrayList();

is equal to 

ArrayList arrColumnLefts;
ArrayList arrColumnWidths  = new ArrayList();

when you call arrColumnLefts.Clear(); you will get null reference exception becouse arrColumnLefts not initialized.

Damith
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  • Thank you. It is worked sir. But, I have a question. Why I cannot wrote `ArrayList arrColumnLefts, arrColumnWidths = new ArrayList` and it is giving an error while the visual studio allowed us to do that? meanwhile, for the `int a, b, c, d = 0` it is works well? – Unknown User Oct 29 '14 at 02:35
  • 1
    from that only arrColumnWidths initialized as `new ArrayList`, arrColumnLefts still having null value; – Damith Oct 29 '14 at 02:37
  • @UnknownUser in that you are declaring 2 types. But you are only initializing / creating one object. That is why it is allowed. Take a look at the 3rd option in Damith's answer above. – deathismyfriend Oct 29 '14 at 02:37
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    @UnknownUser You are incorrect in your above statement. You can declare and initialize your variables on the same line. To initialize a variable you simple do varName = init; So your array list can be initialized like this. ArrayList arrColumnLefts = new ArrayList(), arrColumnWidths = new ArrayList(); All types follow this same method. If you declare variables like this. int int1, int2 = 1; or like this. int int2 = 1, int1; Then int2 is declared and initialized while in1 is only declared and never initialized. – deathismyfriend Oct 29 '14 at 02:56
  • Okay, I understand now. So the shortcut way like `int a, b, c, d, e` is only works when there is no word `new` define. Thank you so much for your explanation sir @Damith and @deathismyfriend – Unknown User Oct 29 '14 at 02:58
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    @UnknownUser No that is not correct. int a, b, c, d, e; are all declared and never initialized. Initialized is referring to setting a variable to something. Ints do not use the new keyword to do this but using = sets the variable to the value. The new keyword is used for classes and others. Both ways initialize a variable. – deathismyfriend Oct 29 '14 at 03:01
  • +1 for your clear explanation sir @deathismyfriend to someone that is not quite understand like me, but now I am understand. Thank you very much. – Unknown User Oct 29 '14 at 03:03
1

Change 

ArrayList arrColumnLefts, arrColumnWidths = new ArrayList();

into 

ArrayList arrColumnLefts = new ArrayList();
ArrayList arrColumnWidths = new ArrayList();

The first line only initializes the second arraylist

Grant Winney
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Maksim Satsikau
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