c# 从零到精通 读取连接数据库-并将读取到的数据添加到dataGridView1 选中状态 全选
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace Test07
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

    private void Form1_Load(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection("server=(local);uid=sa;pwd=;database=db_16");
        con.Open();
        DataSet ds = new DataSet();
        SqlDataAdapter da = new SqlDataAdapter("select * from tb_emp", con);
        da.Fill(ds);
        this.dataGridView1.DataSource = ds.Tables[0].DefaultView;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.dataGridView1.SelectionMode = DataGridViewSelectionMode.RowHeaderSelect;
        int Cont = dataGridView1.GetCellCount(DataGridViewElementStates.Selected);//选取单元格的数目即有行又有列
        if (Cont > 0)
        {
            if (dataGridView1.AreAllCellsSelected(true))//判断是否选重了所有的值。
            {
                MessageBox.Show("你选重了所有的值", "全部选中了");
            }
            else
            {
                System.Text.StringBuilder sb = new System.Text.StringBuilder();

                for (int i = 0; i < Cont; i++)
                {
                    sb.Append("Row: ");
                    sb.Append(dataGridView1.SelectedCells[i].RowIndex.ToString());
                    sb.Append(", Column: ");
                    sb.Append(dataGridView1.SelectedCells[i].ColumnIndex.ToString());
                    sb.Append(Environment.NewLine);
                }
                sb.Append("Total: " + Cont.ToString());
                MessageBox.Show(sb.ToString(), "Selected Cells");
            }
        }
    }
}

}