学步园

 

 

 

问题1、在更新完DataGridView之后如何让滚动条仍然在更新前的位置

答：用 FirstDisplayedScrollingRowIndex和FirstDisplayedScrollingColumnIndex两个属性，参见下面代码。

 

问题2、如果用户在一瞬间连续按快捷键进行更新，不应该响应每一个请求。在下面代码中我们用lastUpdateTime解决了问题。 

        private void dgv_KeyDown(object sender, KeyEventArgs e)
        {
            if(e.KeyCode == Keys.F5 && DateTime.Now.Subtract(_lastUpdateTime).TotalSeconds > 1)
            {
                int row = dgv.FirstDisplayedScrollingRowIndex;
                int col = dgv.FirstDisplayedScrollingColumnIndex;
                LoadLog();
                if (dgv.Rows.Count > 0)
                {
                    row = row < 0 ? 0 : row;
                    if (row >= dgv.Rows.Count)
                        row = dgv.Rows.Count - 1;                        
                    dgv.FirstDisplayedScrollingRowIndex = row;

                    col = col < 0 ? 0 : col;
                    if (col > dgv.Columns.Count)
                        col = dgv.Columns.Count - 1;
                    dgv.FirstDisplayedScrollingColumnIndex = col;
                }
            }
        }

 

 

 

问题3、显示行号：

可以在DataGirdView的RowPostPaint事件中进行绘制。

        private void dgv_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
        {
            DrawRowIndex(sender, e);
        }

        private void DrawRowIndex(object sender, DataGridViewRowPostPaintEventArgs e)
        {
            Rectangle rectangle = new Rectangle(e.RowBounds.Location.X,
               e.RowBounds.Location.Y,
               ((DataGridView)sender).RowHeadersWidth - 4,
               e.RowBounds.Height);

            TextRenderer.DrawText(e.Graphics, (e.RowIndex + 1).ToString(),
                ((DataGridView)sender).RowHeadersDefaultCellStyle.Font,
                rectangle,
                ((DataGridView)sender).RowHeadersDefaultCellStyle.ForeColor,
                TextFormatFlags.VerticalCenter | TextFormatFlags.Right);
        }

参考：

DataGridView 列宽和行高自动调整的设定

DataGridView技巧1