在 DataGridView 中通过 ColumnHeader、RowHeader 和 Cell 启用选择

Question

我正在尝试在DataGridView 中实现类似 excel 的功能。所以：

1. 如果他们选择列标题，它将选择列
2. 如果用户选择行标题，则将选择整行
3. 除此之外，如果他们选择单元格，则只会选择该单个单元格。

因此，对于第三个要求，我将SelectionMode 设置为CellSelect。对于列选择，我选择了列中的所有单元格，但是当我尝试打印 SelectedColumns 时，它打印为零。看来我也必须选择列标题。我不知道如何以编程方式选择列标题。所需的代码如下。谁能告诉我如何做到这一点？

private void dataGridViewFileData_CellMouseUp(object sender, DataGridViewCellMouseEventArgs e)
{
    dataGridViewFileData.MultiSelect = true;
    dataGridViewFileData.SelectionMode = DataGridViewSelectionMode.CellSelect;
    for (int i = 0; i < dataGridViewFileData.Rows.Count; ++i)
         dataGridViewFileData.Rows[i].Cells[0].Selected = true;
    MessageBox.Show("Selected columns:" + dataGridViewFileData.SelectedColumns.Count.ToString());
}

Answer 1

作为一个选项，您可以将SelectionMode 设置为CellSelect，然后处理CellClick 并针对单击的单元格的行索引和列索引并选择该单元格，或整行或整列或全部使用代码的单元格。

由于选择模式为CellSelect，因此选定的列或选定的行为空，如果出于任何原因要跟踪选定的列或选定的行，则需要手动跟踪。

对于选择的视觉反馈也是如此，您需要设置标题的背景颜色或自己绘制它们。例如：

private async void Form1_Load(object sender, EventArgs e)
{
    dataGridView1.ColumnCount = 3;
    dataGridView1.RowCount = 3;
    dataGridView1.SelectionMode = DataGridViewSelectionMode.CellSelect;
    dataGridView1.CellClick += DataGridView1_CellClick;
    dataGridView1.EnableHeadersVisualStyles = false;
}
DataGridViewColumn selectedColumn = null;
DataGridViewRow selectedRow = null;
List<DataGridViewCell> selectedCells = null;
private void DataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
{
    dataGridView1.ClearSelection();

    if (selectedColumn != null)
        selectedColumn.HeaderCell.Style.BackColor =
            dataGridView1.ColumnHeadersDefaultCellStyle.BackColor;
    if (selectedRow != null)
        selectedRow.HeaderCell.Style.BackColor =
            dataGridView1.RowHeadersDefaultCellStyle.BackColor;

    selectedColumn = null;
    selectedRow = null;
    selectedCells = null;
    if (e.ColumnIndex == -1 && e.RowIndex == -1)
    {
        dataGridView1.SelectAll();
        selectedCells = new List<DataGridViewCell>();
        foreach (DataGridViewRow row in dataGridView1.Rows)
            selectedCells.AddRange(row.Cells.Cast<DataGridViewCell>());
    }
    else if (e.ColumnIndex == -1 && e.RowIndex > -1)
    {
        selectedRow = dataGridView1.Rows[e.RowIndex];
        foreach (DataGridViewCell cell in dataGridView1.Rows[e.RowIndex].Cells)
            cell.Selected = true;
    }
    else if (e.ColumnIndex > -1 && e.RowIndex == -1)
    {
        selectedColumn = dataGridView1.Columns[e.ColumnIndex];
        foreach (DataGridViewRow row in dataGridView1.Rows)
            row.Cells[e.ColumnIndex].Selected = true;
    }
    else
    {
        selectedCells = selectedCells = new List<DataGridViewCell>()
            { dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex] };
        dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Selected = true;
    }
    if (selectedColumn != null)
        selectedColumn.HeaderCell.Style.BackColor = SystemColors.Highlight;
    if (selectedRow != null)
        selectedRow.HeaderCell.Style.BackColor = SystemColors.Highlight;
}

Answer 2

作为另一个选项，您可以处理OnCellMouseDown 事件，并根据单击的单元格决定设置SelectionMode。这样就可以得到视觉反馈以及SelectedColumns和SelectedRows：

private void Form1_Load(object sender, EventArgs e)
{
    dataGridView1.ColumnCount = 3;
    dataGridView1.RowCount = 3;
    foreach (DataGridViewColumn c in dataGridView1.Columns)
        c.SortMode = DataGridViewColumnSortMode.NotSortable;
    dataGridView1.CellMouseDown += DataGridView1_CellMouseDown;
}
private void DataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
{
    dataGridView1.ClearSelection();
    if (e.ColumnIndex == -1 && e.RowIndex == -1)
    {
        dataGridView1.SelectionMode = DataGridViewSelectionMode.ColumnHeaderSelect;
        dataGridView1.SelectAll();
    }
    else if (e.ColumnIndex == -1 && e.RowIndex > -1)
    {
        dataGridView1.SelectionMode = DataGridViewSelectionMode.RowHeaderSelect;
        dataGridView1.Rows[e.RowIndex].Selected = true;
    }
    else if (e.ColumnIndex > -1 && e.RowIndex == -1)
    {
        dataGridView1.SelectionMode = DataGridViewSelectionMode.ColumnHeaderSelect;
        dataGridView1.Columns[e.ColumnIndex].Selected = true;
    }
    else
    {
        dataGridView1.SelectionMode = DataGridViewSelectionMode.CellSelect;
        dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Selected = true;
    }
}