DatagridView 常用功能代码

1.DatagridView自动编号

 private void dataGridView1_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
        {
               //自动编号与数据库无关
            Rectangle rectangle = new Rectangle(e.RowBounds.Location.X, e.RowBounds.Location.Y, dataGridView1.RowHeadersWidth - 4,e.RowBounds.Height);
            TextRenderer.DrawText(e.Graphics, (e.RowIndex + 1).ToString(), dataGridView1.RowHeadersDefaultCellStyle.Font, rectangle,
            dataGridView1.RowHeadersDefaultCellStyle.ForeColor, TextFormatFlags.VerticalCenter | TextFormatFlags.Right);

        }

2.DatagridView 导出数据到Excel

private void btnExport_Click(object sender, EventArgs e)
        {
            if (this.openFileDialog1.FileNames.Length == 0)
            {
                MessageBox.Show("请先选择数据源!");
                return;
            }
            
            saveFileDialog.Filter = "Execl files (*.xls)|*.xls";
            saveFileDialog.FileName = "mydata";

            saveFileDialog.FilterIndex = 0;

            saveFileDialog.RestoreDirectory = true;

            saveFileDialog.CreatePrompt = true;

            saveFileDialog.Title = "Export Excel File To";
            saveFileDialog.ShowDialog();
            Stream myStream;

            try
            {
                myStream = saveFileDialog.OpenFile();
            }
            catch
            {
                return;
            }
            //StreamWriter sw = new StreamWriter(myStream, System.Text.Encoding.GetEncoding("gb2312"));
            StreamWriter sw = new StreamWriter(myStream, System.Text.Encoding.GetEncoding(-0));
            string str = "";
            try
            {
                //写标题
                for (int i = 0; i < dataGridView1.ColumnCount; i++)
                {
                    if (i > 0)
                    {
                        str += "\t";
                    }
                    str += dataGridView1.Columns[i].HeaderText;

                }
                sw.WriteLine(str);
                //写内容

                for (int j = 0; j < dataGridView1.Rows.Count; j++)
                {
                    string tempStr = "";

                    for (int k = 0; k < dataGridView1.Columns.Count; k++)
                    {
                        if (k > 0)
                        {
                            tempStr += "\t";
                        }

                        tempStr += dataGridView1.Rows[j].Cells[k].Value.ToString();

                    }
                    sw.WriteLine(tempStr);

                }
                sw.Close();
                myStream.Close();

            }

            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }

            finally
            {
                sw.Close();
                myStream.Close();
            }
        }

 3.DataGridView格式化日期

   private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
        {

            if (e.ColumnIndex == dataGridView1.Columns["PriceDateTime"].Index)
            {
                if (e.Value != null)
                {
                    e.Value = Convert.ToDateTime(e.Value).ToString("yyyy年MM月dd日 hh时mm分");
                }
            }
        }

 4.OpenFileDialog 打开多文件（记得将MultiSelect 这个属性改为True)

  this.openFileDialog1.Filter = "mydata.dat|*.dat";
  this.openFileDialog1.FileName = "";
  this.openFileDialog1.ShowDialog();
  string[] filenames = this.openFileDialog1.FileNames;