Problem in looping.undesired rows of the datagridview are being exported to excel

Question

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Please edit the code because I am unable to export the selected rows of DataGridView to Excel based on Checkbox selection .The below code export all the rows even those rows are not selected(checked) by the user.

What I have tried:

C#

public void exportSelectedRowsToExcel()        {
            // creating Excel Application  
            Microsoft.Office.Interop.Excel._Application app = new Microsoft.Office.Interop.Excel.Application();
            // creating new WorkBook within Excel application  
            Microsoft.Office.Interop.Excel._Workbook workbook = app.Workbooks.Add(Type.Missing);
            // creating new Excelsheet in workbook  
            Microsoft.Office.Interop.Excel._Worksheet worksheet = null;
            // see the excel sheet behind the program  
            app.Visible = true;
            // get the reference of first sheet. By default its name is Sheet1.  
            // store its reference to worksheet  
            worksheet = workbook.Sheets["Sheet1"];
            worksheet = workbook.ActiveSheet;
            // changing the name of active sheet  
            worksheet.Name = DateTime.Now.ToString("yyyyMMddHHmmssfff");

                

            // storing header part in Excel  
            for (int i = 1; i < CategoryGV.Columns.Count + 1; i++)
            {
                worksheet.Cells[1, i] = CategoryGV.Columns[i - 1].HeaderText;
            }

            // storing Each row and column value to excel sheet  
            for (int i = 0; i < CategoryGV.Rows.Count - 1; i++)
            {
                for (int j = 0; j < CategoryGV.Columns.Count; j++)
                {
                    worksheet.Cells[i + 2, j + 1] = Convert.ToString(CategoryGV.Rows[i].Cells[j].Value);
                }
            }


            // save the application 
            workbook.SaveAs(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + 
                 "\\ExportedCategory.xls", Type.Missing, Type.Missing, Type.Missing, Type.Missing, 
                  Type.Missing,Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive, Type.Missing, 
                  Type.Missing, Type.Missing, Type.Missing);
            // Exit from the application  
            app.Quit();
        }

C#

private void btnExportToExcel_Click(object sender, EventArgs e)
        {
            DataGridViewRow row = new DataGridViewRow();

            for (int i = 0; i < CategoryGV.Rows.Count; i++)
            {
                row = CategoryGV.Rows[i];
                if (Convert.ToBoolean(row.Cells["chkBox"].Value))
                {
                    int id = Convert.ToInt16(row.Cells["id"].Value);
                    exportSelectedRowsToExcel();
                    i--;
                }

            }

Posted 3-Dec-19 2:44am

Member 14649908

Updated 3-Dec-19 5:17am

Herman<T>.Instance

v2

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Comments

Herman<T>.Instance 3-Dec-19 9:12am

Wellllll where do you check if the row is selected? row.SelectedIndex is never used

Richard Deeming 3-Dec-19 9:15am

There is nothing in your code to check whether or not the rows are selected. You're just exporting every row.

You just need to add a test inside your loop:
Hide Copy Code

for (int i = 0; i < CategoryGV.Rows.Count - 1; i++)

Edit: In fact, it's worse than that: you're exporting every row multiple times. If you have 10 rows in your grid, and 5 are selected, you export all 10 rows 5 times, overwriting the file each time.

Edit 2: Actually, it's even worse. Thanks to the i-- within the loop in your event handler, if any row is selected, your program will enter an infinite loop, exporting all rows over and over again until you terminate it.

2 solutions

Solution 1

Add the test inside your loop in your exportSelectedRowsToExcel method:

C#

for (int i = 0; i < CategoryGV.Rows.Count - 1; i++)
{
    var row = CategoryGV.Rows[i];
    if (Convert.ToBoolean(row.Cells["chkBox"].Value))
    {
        for (int j = 0; j < CategoryGV.Columns.Count; j++)
        {
            worksheet.Cells[i + 2, j + 1] = Convert.ToString(row.Cells[j].Value);
        }
    }
}

Then change your event handler so that it only exports the rows once:

C#

private void btnExportToExcel_Click(object sender, EventArgs e)
{
    bool haveSelectedRows = false;
    
    for (int i = 0; i < CategoryGV.Rows.Count; i++)
    {
        var row = CategoryGV.Rows[i];
        if (Convert.ToBoolean(row.Cells["chkBox"].Value))
        {
            haveSelectedRows = true;
            break;
        }
    }
    
    if (haveSelectedRows)
    {
        exportSelectedRowsToExcel();
    }
}

Posted 3-Dec-19 3:21am

Richard Deeming

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Ashutosh Gpt · Accepted Answer · 2019-12-03T05:17:00

first get all rows which are selected and pass those rows into your export method.
your export methods exports all cells all the time. ittirate only selected row.

var rows = new List<DataGridViewRow>();
for (int i = 0; i < CategoryGV.Rows.Count; i++)
    {
        var row = CategoryGV.Rows[i];
        if (Convert.ToBoolean(row.Cells["chkBox"].Value))
        {
            rows.add(row);
        }
    }

exportSelectedRowsToExcel(rows);

// storing Each row and column value to excel sheet  
foreach (var row in rows)
{
   for (int j = 0; j < CategoryGV.Columns.Count; j++)
    {
       worksheet.Cells[row.Index, j + 1] = Convert.ToString(row.Cells[j].Value);
     }
}