DataGridView OnRowPostPaint 绘制

Question

实际上，我的代码是“选择悬停”所有行，当我将鼠标悬停在单元格上时，但是，我想更改它，我想选择所有 列，而不是行。

Data Grid

我该如何管理它？

我的代码是：

    protected override void OnRowPostPaint(DataGridViewRowPostPaintEventArgs e)
    {
        base.OnRowPostPaint(e);
        if (this.RectangleToScreen(e.RowBounds).Contains(MousePosition))
        {
            using (var b = new SolidBrush(Color.FromArgb(50, Color.Black)))
            using (var p = new Pen(Color.MediumVioletRed))
            {
                var r = e.RowBounds;
                r.Width -= 1;
                r.Height -= 1;

                e.Graphics.FillRectangle(b, e.RowBounds.X, e.RowBounds.Y,e.RowBounds.Width,  e.RowBounds.Height);
                e.Graphics.DrawRectangle(p, r);

            }


        }
    }

我可以找到相同的方法，但要垂直绘制...

谢谢

Answer 1

如果您只想在鼠标悬停在任何单元格上时选择整列，则不必使用 OnRowPostPaint 事件，您可以使整个网格的选择模式选择整列而不是仅选择一个单元格或整行但要做到这一点，您需要将列的 SortMode 设置为自动以外的任何值。这是怎么做的：

private void Form1_Load(object sender, EventArgs e)
{
  for (int i = 0; i < dataGridView1.ColumnCount; i++)
  {
    dataGridView1.Columns[i].SortMode = DataGridViewColumnSortMode.NotSortable;
  }
  dataGridView1.SelectionMode = DataGridViewSelectionMode.FullColumnSelect;
}

然后使用 OnCellMouseEnter 或 OnCellMouseMove 事件来选择整个列，如下所示：

private void OnCellMouseMove(object sender, DataGridViewCellMouseEventArgs e)
{
  if (e.RowIndex == -1 || e.ColumnIndex == -1)
    return;
  dataGridView1.CurrentCell = dataGridView1[e.ColumnIndex, e.RowIndex];
}

有关选择整列的更多信息，请参阅此Answer。

Answer 2

也许不是你想要的，但也许这个例子可以让你开始：

private void dataGridView1_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
    {

        Rectangle newRect = new Rectangle(e.CellBounds.X + 1,
            e.CellBounds.Y + 1, e.CellBounds.Width - 4,
            e.CellBounds.Height - 4);

        using (
            Brush gridBrush = new SolidBrush(this.dataGridView1.GridColor),
            backColorBrush = new SolidBrush(e.CellStyle.BackColor))
        {
            using (Pen gridLinePen = new Pen(gridBrush))
            {
                // Erase the cell.
                e.Graphics.FillRectangle(backColorBrush, e.CellBounds);

                // Draw the grid lines (only the right and bottom lines;
                // DataGridView takes care of the others).
                e.Graphics.DrawLine(gridLinePen, e.CellBounds.Left,
                    e.CellBounds.Bottom - 1, e.CellBounds.Right - 1,
                    e.CellBounds.Bottom - 1);
                e.Graphics.DrawLine(gridLinePen, e.CellBounds.Right - 1,
                    e.CellBounds.Top, e.CellBounds.Right - 1,
                    e.CellBounds.Bottom);

                // Draw the inset highlight box.
                e.Graphics.DrawRectangle(Pens.Blue, newRect);

                // Draw the text content of the cell, ignoring alignment.
                if (e.Value != null)
                {
                    e.Graphics.DrawString((String)e.Value, e.CellStyle.Font,
                        Brushes.Crimson, e.CellBounds.X + 2,
                        e.CellBounds.Y + 2, StringFormat.GenericDefault);
                }
                e.Handled = true;
            }
        }
    }

示例来自本页docs.microsoft.com DataGridView.OnCellPainting

Answer 3

这将选择悬停列中的所有单元格...尽管您的要求并不清楚。

using System.Windows.Forms;

namespace DatagridViewSelectAllCells_58842788
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            dataGridView1.Columns.Add(new DataGridViewTextBoxColumn());
            dataGridView1.Columns.Add(new DataGridViewTextBoxColumn());
            for (int i = 0; i < 10; i++)
            {
                dataGridView1.Rows.Add($"col1_{i}", $"col2_{i}");
            }
            dataGridView1.CellMouseEnter += DataGridView1_CellMouseEnter;
        }

        private void DataGridView1_CellMouseEnter(object sender, DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex == -1)//don't do anything if the rowheader is being hovered
            {
                return;
            }
            if (dataGridView1.SelectedCells.Count > 1 && e.ColumnIndex == dataGridView1.SelectedCells[0].ColumnIndex)//don't do anything if the column is already selected
            {
                return;
            }
            dataGridView1.ClearSelection();//clear the current selection

            //select all the cells in that hovered column
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                dataGridView1[e.ColumnIndex, i].Selected = true;
            }
        }
    }
}

这里是更改单元格颜色的更新答案

using System.Windows.Forms;
using System.Drawing;

namespace DatagridViewSelectAllCells_58842788
{
    public partial class Form1 : Form
    {
        static Color originalColor;
        static int highlightedCol = -1;
        static DataGridView dataGridView1 = new DataGridView();
        public Form1()
        {
            InitializeComponent();
            Controls.Add(dataGridView1);
            dataGridView1.Dock = DockStyle.Fill;
            dataGridView1.Columns.Add(new DataGridViewTextBoxColumn());
            dataGridView1.Columns.Add(new DataGridViewTextBoxColumn());
            for (int i = 0; i < 10; i++)
            {
                dataGridView1.Rows.Add($"col1_{i}", $"col2_{i}");
            }
            dataGridView1.CellMouseEnter += DataGridView1_CellMouseEnter;
            dataGridView1.CellMouseLeave += DataGridView1_CellMouseLeave;

            dataGridView1[1, 4].Style.BackColor = Color.DarkOliveGreen;
        }

        private void DataGridView1_CellMouseLeave(object sender, DataGridViewCellEventArgs e)
        {
            //WithCellStyle(sender, e, "Leave");
            WithDefaultStyle(sender, e, "Leave");
        }

        private void DataGridView1_CellMouseEnter(object sender, DataGridViewCellEventArgs e)
        {
            //WithCellStyle(sender, e, "Enter");
            WithDefaultStyle(sender, e, "Enter");
        }


        /*
         * to handle cells that have specific style attributes
         * like cell dataGridView1[1, 4]
         * there would be more to this to keep track of multiple different cell styles on the Leave side of thing
         * but that's up to you to handle if you have a need for it.
         */
        private static void WithCellStyle(object sender, DataGridViewCellEventArgs e, string eType)
        {
            switch (eType)
            {
                case "Enter":
                    if (originalColor == null)
                    {
                        originalColor = ((Control)sender).BackColor;//store the color for leave event
                    }
                    highlightedCol = e.ColumnIndex;//set which column is highlighted for leave event

                    for (int i = 0; i < dataGridView1.Rows.Count; i++)
                    {
                        dataGridView1[highlightedCol, i].Style.BackColor = Color.Aquamarine;
                    }
                    break;
                case "Leave":
                    for (int i = 0; i < dataGridView1.Rows.Count; i++)
                    {
                        dataGridView1[highlightedCol, i].Style.BackColor = originalColor;
                    }
                    break;
                default:
                    break;
            }
        }

        /*
         * if you only have default styles
         */
        private static void WithDefaultStyle(object sender, DataGridViewCellEventArgs e, string eType)
        {
            switch (eType)
            {
                case "Enter":
                    if (originalColor == null)
                    {
                        originalColor = ((Control)sender).BackColor;//store the color for leave event
                    }
                    highlightedCol = e.ColumnIndex;//set which column is highlighted for leave event

                    //change color of all the cells
                    dataGridView1.Columns[highlightedCol].DefaultCellStyle.BackColor = Color.Aquamarine;//set the new color
                    break;
                case "Leave":
                    //per defaultstyle
                    dataGridView1.Columns[highlightedCol].DefaultCellStyle.BackColor = originalColor;
                    break;
                default:
                    break;
            }
        }
    }
}