Exporting datagridview to csv file

Question

I'm working on a application which will export my DataGridView called scannerDataGridView to a csv file.

Found some example code to do this, but can't get it working. Btw my datagrid isn't databound to a source.

When i try to use the Streamwriter to only write the column headers everything goes well, but when i try to export the whole datagrid including data i get an exeption trhown.

System.NullReferenceException: Object reference not set to an instance of an object. at Scanmonitor.Form1.button1_Click(Object sender, EventArgs e)

Here is my Code, error is given on the following line:

dataFromGrid = dataFromGrid + ',' + dataRowObject.Cells[i].Value.ToString();

//csvFileWriter = StreamWriter
//scannerDataGridView = DataGridView   

private void button1_Click(object sender, EventArgs e)
{
    string CsvFpath = @"C:\scanner\CSV-EXPORT.csv";
    try
    {
        System.IO.StreamWriter csvFileWriter = new StreamWriter(CsvFpath, false);

        string columnHeaderText = "";

        int countColumn = scannerDataGridView.ColumnCount - 1;

        if (countColumn >= 0)
        {
            columnHeaderText = scannerDataGridView.Columns[0].HeaderText;
        }

        for (int i = 1; i <= countColumn; i++)
        {
            columnHeaderText = columnHeaderText + ',' + scannerDataGridView.Columns[i].HeaderText;
        }


        csvFileWriter.WriteLine(columnHeaderText);

        foreach (DataGridViewRow dataRowObject in scannerDataGridView.Rows)
        {
            if (!dataRowObject.IsNewRow)
            {
                string dataFromGrid = "";

                dataFromGrid = dataRowObject.Cells[0].Value.ToString();

                for (int i = 1; i <= countColumn; i++)
                {
                    dataFromGrid = dataFromGrid + ',' + dataRowObject.Cells[i].Value.ToString();

                    csvFileWriter.WriteLine(dataFromGrid);
                }
            }
        }


        csvFileWriter.Flush();
        csvFileWriter.Close();
    }
    catch (Exception exceptionObject)
    {
        MessageBox.Show(exceptionObject.ToString());
    }

Answer 1

Found the problem, the coding was fine but i had an empty cell that gave the problem.

Answer 2

I think this is the correct for your SaveToCSV function : ( otherwise Null ...)

 for (int i = 0; i < columnCount; i++)

Not :

 for (int i = 1; (i - 1) < DGV.RowCount; i++)

Answer 3

      Please check this code.its working fine  

          try
               {
            //Build the CSV file data as a Comma separated string.
            string csv = string.Empty;

            //Add the Header row for CSV file.
            foreach (DataGridViewColumn column in dataGridView1.Columns)
            {
                csv += column.HeaderText + ',';
            }
            //Add new line.
            csv += "\r\n";

            //Adding the Rows

            foreach (DataGridViewRow row in dataGridView1.Rows)
            {
                foreach (DataGridViewCell cell in row.Cells)
                {
                    if (cell.Value != null)
                    {
                        //Add the Data rows.
                        csv += cell.Value.ToString().TrimEnd(',').Replace(",", ";") + ',';
                    }
                    // break;
                }
                //Add new line.
                csv += "\r\n";
            }

            //Exporting to CSV.
            string folderPath = "C:\\CSV\\";
            if (!Directory.Exists(folderPath))
            {
                Directory.CreateDirectory(folderPath);
            }
            File.WriteAllText(folderPath + "Invoice.csv", csv);
            MessageBox.Show("");
        }
        catch
        {
            MessageBox.Show("");
        }

Answer 4

Your code was almost there... But I made the following corrections and it works great. Thanks for the post.

Error:

string[] output = new string[dgvLista_Apl_Geral.RowCount + 1];

Correction:

string[] output = new string[DGV.RowCount + 1];

Error:

System.IO.File.WriteAllLines(filename, output, System.Text.Encoding.UTF8);

Correction:

System.IO.File.WriteAllLines(sfd.FileName, output, System.Text.Encoding.UTF8);

Answer 5

The line "csvFileWriter.WriteLine(dataFromGrid);" should be moved down one line below the closing bracket, else you'll get a lot of repeating results:

for (int i = 1; i <= countColumn; i++)
{
dataFromGrid = dataFromGrid + ',' + dataRowObject.Cells[i].Value.ToString();
}
csvFileWriter.WriteLine(dataFromGrid);

Answer 6

I know this is probably already dead but I made a simple code that creates a CSV based on a DataGridView object and asks where you want to save it.

Its pretty straight forward, just paste de function and use it. It already has some basic exception handling so is pretty safe to use. enjoy.

    private void SaveToCSV(DataGridView DGV)
    {
        string filename = "";
        SaveFileDialog sfd = new SaveFileDialog();
        sfd.Filter = "CSV (*.csv)|*.csv";
        sfd.FileName = "Output.csv";
        if (sfd.ShowDialog() == DialogResult.OK)
        {
            MessageBox.Show("Data will be exported and you will be notified when it is ready.");
            if (File.Exists(filename))
            {
                try
                {
                    File.Delete(filename);
                }
                catch (IOException ex)
                {
                    MessageBox.Show("It wasn't possible to write the data to the disk." + ex.Message);
                }
            }
            int columnCount = DGV.ColumnCount;
            string columnNames = "";
            string[] output = new string[DGV.RowCount + 1];
            for (int i = 0; i < columnCount; i++)
            {
                columnNames += DGV.Columns[i].Name.ToString() + ",";
            }
            output[0] += columnNames;
            for (int i = 1; (i - 1) < DGV.RowCount; i++)
            {
                for (int j = 0; j < columnCount; j++)
                {
                    output[i] += DGV.Rows[i - 1].Cells[j].Value.ToString() + ",";
                }
            }
            System.IO.File.WriteAllLines(sfd.FileName, output, System.Text.Encoding.UTF8);
            MessageBox.Show("Your file was generated and its ready for use.");
        }
    }

EDIT: changed ';' to ',' since we are talking about CSV files