CODEWITHSUNDEEP
c#datagridviewstreamwriter
PandaNL
PandaNL

Reputation: 848

Exporting datagridview to csv file

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());
    }

Upvotes: 19

Views: 83352

Answers (8)

Gray Programmerz
Gray Programmerz

Reputation: 609

This is what I been using in my projects:

void export_csv(string file, DataGridView grid)
{
    using (StreamWriter csv = new StreamWriter(file, false))
    {
        int totalcolms = grid.ColumnCount;
        foreach (DataGridViewColumn colm in grid.Columns) csv.Write(colm.HeaderText + ',');
        csv.Write('\n');
        string data = "";
        foreach (DataGridViewRow row in grid.Rows)
        {
            if (row.IsNewRow) continue;
            data = "";
            for (int i = 0; i < totalcolms; i++)
            {
                data += (row.Cells[i].Value ?? "").ToString() + ',';
            }
            if (data != string.Empty) csv.WriteLine(data);
        }
    }

}

Upvotes: 0

Manish sharma
Manish sharma

Reputation: 536

      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("");
        }

Upvotes: 4

threefx
threefx

Reputation: 81

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++)

Upvotes: 0

Adam White
Adam White

Reputation: 3390

A little known feature of the DataGridView is the ability to programmatically select some or all of the DataGridCells, and send them to a DataObject using the method DataGridView.GetClipboardContent(). Whats the advantage of this then?

A DataObject doesn't just store an object, but rather the representation of that object in various different formats. This is how the Clipboard is able to work its magic; it has various formats stored and different controls/classes can specify which format they wish to accept. In this case, the DataGridView will store the selected cells in the DataObject as a tab-delimited text format, a CSV format, or as HTML (*).

The contents of the DataObject can be retrieved by calling the DataObject.GetData() or DataObject.GetText() methods and specifying a predefined data format enum. In this case, we want the format to be TextDataFormat.CommaSeparatedValue for CSV, then we can just write that result to a file using System.IO.File class.

(*) Actually, what it returns is not, strictly speaking, HTML. This format will also contain a data header that you were not expecting. While the header does contain the starting position of the HTML, I just discard anything above the HTML tag like myString.Substring(IndexOf("<HTML>"));.

Observe the following code:

void SaveDataGridViewToCSV(string filename)
{        
    // Choose whether to write header. Use EnableWithoutHeaderText instead to omit header.
    dataGridView1.ClipboardCopyMode = DataGridViewClipboardCopyMode.EnableAlwaysIncludeHeaderText;
    // Select all the cells
    dataGridView1.SelectAll();
    // Copy selected cells to DataObject
    DataObject dataObject = dataGridView1.GetClipboardContent();
    // Get the text of the DataObject, and serialize it to a file
    File.WriteAllText(filename, dataObject.GetText(TextDataFormat.CommaSeparatedValue));
}

Now, isn't that better? Why re-invent the wheel?

Hope this helps...

Upvotes: 24

GSIT Coder
GSIT Coder

Reputation: 21

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);

Upvotes: 2

Jonathan
Jonathan

Reputation: 7541

LINQ FTW!

var sb = new StringBuilder();

var headers = dataGridView1.Columns.Cast<DataGridViewColumn>();
sb.AppendLine(string.Join(",", headers.Select(column => "\"" + column.HeaderText + "\"").ToArray()));

foreach (DataGridViewRow row in dataGridView1.Rows)
{
    var cells = row.Cells.Cast<DataGridViewCell>();
    sb.AppendLine(string.Join(",", cells.Select(cell => "\"" + cell.Value + "\"").ToArray()));
}

And indeed, c.Value.ToString() will throw on null value, while c.Value will correctly convert to an empty string.

Upvotes: 40

l0calh0st
l0calh0st

Reputation: 11

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);

Upvotes: 1

PandaNL
PandaNL

Reputation: 848

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

Upvotes: 2

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