C#----动态加载DataGridView中DataGridViewComboBoxColumn中的值

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

namespace Sys
{
    public partial class Form3 : Form
     {
        public Form3()
         {
             InitializeComponent();
         }

        private void Form3_Load(object sender, EventArgs e)
         {
             dataGridView1.AllowUserToAddRows = false;
             dataGridView1.AutoGenerateColumns = false;

            using (SqlConnection sqlconn = new SqlConnection("server=.;uid=sa;pwd=sa;database=xx"))
             {
                string sql1 = @"select userid,fullname,a.[description],b.ugroupid
                                 from users a left outer join usergroup b
                                 on a.grade=b.ugroupid";
                string sql2 = "select distinct ugroupid,[description] from usergroup";

                 DataGridViewComboBoxColumn dgvComboBoxColumn = dataGridView1.Columns["grade"] as DataGridViewComboBoxColumn;
                 dgvComboBoxColumn.DataPropertyName = "ugroupid";
                 dgvComboBoxColumn.DataSource = GetTable(sql2).DefaultView;//必须在设置dataGridView1的DataSource的属性前设置
                 dgvComboBoxColumn.DisplayMember = "description";
                 dgvComboBoxColumn.ValueMember = "ugroupid";

                 dataGridView1.DataSource = GetTable(sql1).DefaultView;//一定要在dgvComboBoxColumn的DataSource后设置
             }
         }

        private DataTable GetTable(string sql)
         {
            using (SqlConnection sqlconn = new SqlConnection("server=.;uid=sa;pwd=yuling1310;database=smls"))
             {
                 DataTable dt = new DataTable();
                 SqlDataAdapter sqlda = new SqlDataAdapter(sql, sqlconn);
                 sqlda.Fill(dt);
                return dt;
             }
         }
     }
}
注意事项：
.注意其ValueMember的DataType与DataPropertyName对应的列的DataType要相同，他不会为你做类型转换的。
2.编程设置显示样式时注意一定要在设置DataSource之前设置DataGridViewComboBoxColumn的DataSource等属性。