how select multiple row using shift and Ctrl key in datagridview C#

Question

My requirement : In datagridview I need select row by clicking the row header and selected row should maintain until I will click the other row header also same time I should select cell too.

My Problem : I can't select multiple row using Shift and Ctrl key.

my code :

    List< DataGridViewRow> selectedRows = new List< DataGridViewRow>();

    void selectRows()
    {
        dataGridView1.SuspendLayout();
        foreach (DataGridViewRow r in dataGridView1.Rows)
        {
            r.Selected = selectedRows.Contains(r);
        }
        dataGridView1.ResumeLayout();
    }

    private void dataGridView1_RowHeaderMouseClick(object sender,DataGridViewCellMouseEventArgs e)
    {
        DataGridViewRow clickedRow = dataGridView1.CurrentRow;

        if (selectedRows.Contains(clickedRow))
        {
            selectedRows.Remove(clickedRow);
        }
        else
        {
            selectedRows.Add(clickedRow);
        }
        selectRows();

        foreach (DataGridViewRow row in dataGridView1.Rows)
        {
            if ((row.Index != e.RowIndex) && !row.Selected)
            {
                row.DefaultCellStyle.BackColor = Color.White;
            }
            else
            {
                selectedRows.Remove(clickedRow);
                row.Selected = true;
                row.DefaultCellStyle.BackColor = Color.Blue;
            }
        }
    }

    private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
    {
        foreach (DataGridViewRow row in dataGridView1.Rows)
        {
            if (row.DefaultCellStyle.BackColor == Color.Blue)
            {
                row.Selected = true;
            }
        }
    }

Answer 1

您必须设置为启用datagridview的multiselect dataGridView.MultiSelect = true;

Answer 2

Be familiar with using a debugger, you will be able to find out where the issue is.

You are clearing the selection in your loop

foreach (DataGridViewRow row in dataGridView1.Rows)
{
}

Rethink the if-else logic in it and you will see why. You are clearing your previous selections when you are not suppose to.