Why dictionary puts data inside [] mark?

[Alex Dunlop]

Hi,

{
if (DataGridView2.Rows.Count != 0 && !string.IsNullOrEmpty(column_num.Text) && !string.IsNullOrEmpty(row_num.Text) && !string.IsNullOrEmpty(Equip_column.Text) && !string.IsNullOrEmpty(prog_num.Text))
{
for (int i = Convert.ToInt32(row_num.Text); i < DataGridView2.Rows.Count; i++)
{
if (!code_dic.ContainsKey(DataGridView2.Rows[i].Cells[Convert.ToInt32(column_num.Text)].Value.ToString()))
{
code_dic.Add(DataGridView2.Rows[i].Cells[Convert.ToInt32(column_num.Text)].Value.ToString(), string.Join(",", DataGridView2.Rows[i].Cells[Convert.ToInt32(Equip_column.Text)].Value.ToString(), prog_num.Text.ToString()));
}
}
}

        foreach (KeyValuePair pair in code\_dic)
        {
            string\[\] my\_arr = pair.ToString().Split(',');
            my\_table\_code.Rows.Add(my\_arr\[0\], my\_arr\[1\], my\_arr\[2\]);
            DataGridView3.DataSource = my\_table\_code;
        }
    }

mark. The output show information like this: [abc,def,ghi] I want to omit[ ] marks. What to do?