public partial class SelectForm : Form    {        public string ReturnStr = "", ColumnValuehttp://www.mamicode.com/= "", sql = "";        int ColumnIndex;        DataTable dt = null;        /// <summary>        ///         /// </summary>        /// <param name="sql">sql语句</param>        /// <param name="ColumnValue">返回值的列名</param>        public SelectForm(string sql, string ColumnValue)        {            this.ColumnValue = http://www.mamicode.com/ColumnValue;"sender"></param>        /// <param name="e"></param>        private void SelectForm_Load(object sender, EventArgs e)        {            dataGrid.CellDoubleClick += dataGrid_CellDoubleClick;//单元格Cell双击事件            DataBind();        }        /// <summary>        /// 数据绑定        /// </summary>        private void DataBind()        {            dt = GetDataTable();//根据sql语句绑定数据库            ColumnIndex = dt.Columns.IndexOf(ColumnValue);            dataGrid.DataSource = dt;        }        /// <summary>        /// 根据sql语句，返回datatable        /// </summary>        /// <returns></returns>        private DataTable GetDataTable()        {            SqlConnectionStringBuilder sb = new SqlConnectionStringBuilder();            sb.DataSource = "liurt-pc";            sb.InitialCatalog = "mydb";            sb.UserID = "sa";            sb.Password = "qaz123";            using (SqlConnection con = new SqlConnection(sb.ToString()))            {                SqlDataAdapter da = new SqlDataAdapter(sql, con);                DataTable dt = new DataTable();                da.Fill(dt);                return dt;            }        }        private void dataGrid_CellDoubleClick(object sender, DataGridViewCellEventArgs e)        {            if (e.RowIndex > -1)            {                ReturnStr = dataGrid.Rows[e.RowIndex].Cells[ColumnIndex].Value.ToString();                this.Close();            }        }        private void txtValue_TextChanged(object sender, EventArgs e)        {            DataRow[] drs = dt.Select(ColumnValue + " like ‘%" + txtValue.Text + "%‘");            if (drs.Length == 0)            {                dataGrid.DataSource = null;            }            else            {                dataGrid.DataSource = drs.CopyToDataTable();            }        }        private void dataGrid_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)        {            if (e.RowIndex % 2 != 0)            { e.CellStyle.BackColor = Color.GreenYellow; }             else             { e.CellStyle.BackColor = Color.MintCream; }        }    }