c＃-将DataGridView转换为txt…同一行问题上的标题和第一行

Question

I am attempting to export data from a datagridview into a .txt table of sorts.

When I export to the .txt, the header prints on the first line like it is supposed too, but the first row of the table prints on that line too...Now I have tried a number of things but, obviously my logic is very wrong here.

I basically want a way to set dataGridView_Excel.Rows.Count - 1; to just the normal count without the -1. But every time I do it throws a Object reference not set to an instance of an object. Or if I try to increase the column count to counteract that I get a Index was out of range. Must be non-negative and less than the size of the collection. Any suggestions on how to do this better? I understand why its happening, my logic to fix it just isn't sound and I am beyond confused.

if (save.ShowDialog() == DialogResult.OK)
        {
            TextWriter writer = new StreamWriter(save.OpenFile());

            int i2 = 0;
            while (i2 < 19)
            {
                writer.Write(dataGridView_Excel.Columns[i2].HeaderText + "\t        " + "|");
                i2++;
            }

            for (int i = 0; i < dataGridView_Excel.Rows.Count - 1; i++)
            {                                      
                for (int j = 0; j < dataGridView_Excel.Columns.Count; j++)
                {
                    writer.Write("\t" + dataGridView_Excel.Rows[i].Cells[j].Value.ToString() + "\t        " + "|");

                }

                writer.WriteLine("");
                writer.WriteLine("--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------");
            }
            writer.Close();
            MessageBox.Show("Data Exported");

Answer 1

Your DataGridView is 0-indexed and has 'count' total rows. This line: for (int i = 0; i < dataGridView_Excel.Rows.Count - 1; i++)

Will start at zero and go to the ((numbers of rows -1)-1), because it is < : Less than.

Try:

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

ie add in the = sign, or:

for (int i = 0; i < dataGridView_Excel.Rows.Count; i++)

Unless I've misunderstood your issue. Is the issue the looping, or is it getting things to write on a new line?

To get it to write a new line, try adding Environment.NewLine to the end:

writer.Write("\t" + dataGridView_Excel.Rows[i].Cells[j].Value.ToString() + "\t        " + "|" + Environment.NewLine);

Answer 2

Just a case of looking at something too long and getting distracted...oops

Here is the easiest way around this:

if (save.ShowDialog() == DialogResult.OK)
        {
            TextWriter writer = new StreamWriter(save.OpenFile());

            int i2 = 0;
            while (i2 < 20)
            {
                writer.Write(dataGridView_Excel.Columns[i2].HeaderText + "\t        " + "|");
                i2++;
            }

            writer.Write(Environment.NewLine);
            writer.WriteLine("-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------");

            for (int i = 0; i < dataGridView_Excel.Rows.Count - 1; i++)
            {                                      
                for (int j = 0; j < dataGridView_Excel.Columns.Count; j++)
                {
                    writer.Write("\t" + dataGridView_Excel.Rows[i].Cells[j].Value.ToString() + "\t        " + "|");

                }

                writer.WriteLine("");
                writer.WriteLine("--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------");
            }
            writer.Close();
            MessageBox.Show("Data Exported");
        }

I just added a Environment.NewLine and my ---- divider before the loop. The whole reason I added the Header to the file in a while loop outside the main for loop was for easy changes down the road to the .txt format. Thank you for the idea @ainwood it set me back on track!

Before

After!