问创建选择相同列的某些元素的网格视图事件

EN

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace gridview
{
    public partial class Form1 : Form
    {
        bool buttonIsPressed = false;
        int rowIndex, columnIndex;

        public Form1()
        {
            InitializeComponent();
            completeDataGridview();
        }

        //this function only creates a filled DataGridView
        private void completeDataGridview()
        {
            dataGridView1.RowCount = 3;
            for (int x = 0; x < 3; x++)
            {
                for (int y = 0; y < 3; y++)
                {
                    dataGridView1.Rows[x].Cells[y].Value = ((char)(97 + y + 3 * x)).ToString();
                }
            }

            // this part is stolen from http://stackoverflow.com/questions/7412098/fit-datagridview-size-to-rows-and-columnss-total-size
            int height = 0;
            foreach (DataGridViewRow row in dataGridView1.Rows)
            {
                height += row.Height;
            }
            height += dataGridView1.ColumnHeadersHeight;

            int width = 0;
            foreach (DataGridViewColumn col in dataGridView1.Columns)
            {
                width += col.Width;
            }
            width += dataGridView1.RowHeadersWidth;

            dataGridView1.ClientSize = new Size(width + 2, height);

        }

        private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
        {
            buttonIsPressed = true;
            rowIndex = e.RowIndex;
            columnIndex = e.ColumnIndex;            
        }

        private void dataGridView1_CellMouseUp(object sender, DataGridViewCellMouseEventArgs e)
        {
            if (buttonIsPressed)
            {
                int startingRow = 0;
                if (rowIndex > e.RowIndex)
                    startingRow = e.RowIndex;
                else
                    startingRow = rowIndex;

                //at first we have to deselect every cell
                deselectEveryCell();

                //then reselect the old ones
                int amountOfRows = Math.Abs(rowIndex - e.RowIndex) + 1;
                for (int x = 0; x < amountOfRows; x++)
                {
                    dataGridView1.Rows[startingRow + x].Cells[columnIndex].Selected = true;
                }
            }
            buttonIsPressed = false;
        }

        private void deselectEveryCell()
        {
            for (int x = 0; x < dataGridView1.RowCount; x++)
            {
                for (int y = 0; y < dataGridView1.ColumnCount; y++)
                {
                    dataGridView1.Rows[x].Cells[y].Selected = false;
                }
            }
        }

        private void dataGridView1_MouseLeave(object sender, EventArgs e)
        {
            if (buttonIsPressed)
                deselectEveryCell();
        }
    }
}