object reference not set to an instance of an object

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I am exporting the contents of datagridview to excel but while exporting i get the above error. the code is:

C#

private void btn_GenerateXL_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.IsBusy)
            {
                msgBox.CustomMessage = m_resourceManger.GetString("Background Busy");
                msgBox.MessageType = Constant.Warning;
                msgBox.ShowDialog();
            }
            else
            {
                ShowUIMessage(Constant.Info, m_resourceManger.GetString("ButtonClicked"));
                try
                {
                    if (dgvPopulateData.Rows.Count > 0)
                    {
                        btn_PopulateGrid.Enabled = false;
                        Excel.ApplicationClass excel = null;
                        Excel.Workbook xlWorkBook = null;
                        Excel.Worksheet xlWorkSheetData = null;
                        Excel.Worksheet xlWorkSheetHelp = null;
                        Excel.Range range = null;
                        Excel.Sheets xlWorkSheets = null;
                        Excel.FormatCondition condition = null;
                        Excel.Application xlApp;
                        object misValue = System.Reflection.Missing.Value;
                        excel = new Excel.ApplicationClass();
                        excel.Application.Workbooks.Add(Type.Missing);
                        Int16 i, j;
                        xlWorkBook = excel.Application.Workbooks[1];
                        xlWorkSheets = xlWorkBook.Worksheets;
                        xlWorkSheetData = (Excel.Worksheet)xlWorkSheets.get_Item(1);
                        xlWorkSheetData.Name = "Language_Data";

                        for (i = 1; i < dgvPopulateData.Columns.Count + 1; i++)
                        {
                            xlWorkSheetData.Cells[1, i] = dgvPopulateData.Columns[i - 1].HeaderText;
                        }
                        // storing Each row and column value to excel sheet 
                        for (i = 0; i < dgvPopulateData.Rows.Count - 1; i++)
                        {
                            for (j = 0; j < dgvPopulateData.Columns.Count; j++)
                            {
                                if (!string.IsNullOrEmpty(dgvPopulateData.Rows[i].Cells[j].Value.ToString()) || dgvPopulateData.Rows[i].Cells[j].Value.ToString().Trim().Length == 0)
                                {
                                    continue;
                                }
                                
                                xlWorkSheetData.Cells[i + 2, j + 1] = dgvPopulateData.Rows[i].Cells[j].Value.ToString();// When i's value becomes 2 and comes to above line it shows this error.
                            }
                        }

                        xlWorkBook.SaveAs(@"c:\csharp.net-informations.xls", Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue, Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
                        xlWorkBook.Close(true, misValue, misValue);
                        excel.Quit();

                        releaseObject(xlWorkSheetData);
                        releaseObject(xlWorkBook);
                        releaseObject(excel);
                        msgBox.CustomMessage = m_resourceManger.GetString("ExcelGen");
                        msgBox.MessageType = Constant.Info;
                        msgBox.ShowDialog();
                        backgroundWorker1.RunWorkerAsync();
                        btn_PopulateGrid.Enabled = true;
                        ShowUIMessage(Constant.Info, m_resourceManger.GetString("ExcelGen"));
                    }
                    else
                    {
                        ShowUIMessage(Constant.Error, m_resourceManger.GetString("GridEmpty"));
                    }
                }
                catch (Exception Ex)
                {
                    ShowUIMessage(Constant.Error, Constant.ErrorMsg + Ex.Message.ToString());
                }
            }
        }

        private void releaseObject(object obj)
        {
            try
            {
                System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
                obj = null;
            }
            catch (Exception ex)
            {
                obj = null;
                MessageBox.Show("Exception Occured while releasing object " + ex.ToString());
            }
            finally
            {
                GC.Collect();
            }
        }

-------------------------------------------------------------------------------------
xlWorkSheetData.Cells[i + 2, j + 1] = dgvPopulateData.Rows[i].Cells[j].Value.ToString(); here i am getting the error.

my gridview is like this:-

id   name  department
1     dh     uhu33
2     jej    dvv12
             egfeg12
3     udhf   nsd12
             ndfi23

i want to export it as it is. Help me plz. Thanks in Advance

Posted 9-Aug-12 2:42am

Amit Roy

Updated 9-Aug-12 3:04am

v3

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Comments

[no name] 9-Aug-12 9:01am

Either rows[i] is null or cells[j] is null. You are off by one probably.

4 solutions

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Santhosh Kumar Jayaraman · Answer 1 · 2012-08-09T02:46:00

Solution 1

am not sure. But its worth try. You should loop till count-1 here

C#

for (j = 0; j < dgvPopulateData.Columns.Count-1; j++)
{

Posted 9-Aug-12 2:46am

Santhosh Kumar Jayaraman

v2

Comments

Christian Amado 9-Aug-12 8:49am

50% of the answer, i think. He has a reference error not index exception. May be xlWorkSheetData or the value of the cell is null.

Amit Roy 9-Aug-12 8:55am

for (j = 0; j < dgvPopulateData.Columns.Count-1; j++)
{
Again getting same error

Amit Roy 9-Aug-12 8:57am

2 jej dvv12
egfeg12// getting error due to this row
3 udhf nsd12
ndfi23

**AmitGajjar** · Answer 2 · 2012-08-09T03:11:00

Hi,

In the given line of code from where you are getting error,

i.e.

C#

xlWorkSheetData.Cells[i + 2, j + 1] = dgvPopulateData.Rows[i].Cells[j].Value.ToString();

the possibility i can see for the error message is either .Value or .ToString(). You need checking for Null value of

dgvPopulateData.Rows[i].Cells[j]

check if HashValue method available if so , use it to check if data is available. or you can simply check for Null.

So you code would be like,

C#

if(dgvPopulateData.Rows[i].Cells[j] != null)
{
xlWorkSheetData.Cells[i + 2, j + 1] = dgvPopulateData.Rows[i].Cells[j].Value.ToString();
}

Hope this will resolve your issue,

Thanks
-Amit Gajjar.

Aditya Mangipudi · Answer 3 · 2012-08-09T03:16:00

Solution 3

You are taking i from 0 to count-1 and then checking for value .cells[i+2]

Posted 9-Aug-12 3:16am

Aditya Mangipudi

Comments

Amit Roy 10-Aug-12 1:07am

I think i can't fix this bug...

Amit Roy · Answer 4 · 2012-08-12T19:07:00

Solution 4

Since this approach was not working for me. i had to do it using another approach or a simple aproach. Populating the excel column wise one by one. Thank you all who helped me or tried to help me.

Posted 12-Aug-12 19:07pm

Amit Roy

object reference not set to an instance of an object

4 solutions

Solution 1

Solution 2

Solution 3

Solution 4

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