C# 通讯录管理系统 新增，修改，查询···

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; using System.Configuration; namespace PhoneBook { public partial class frmMain : Form { public frmMain() { InitializeComponent(); } private string strConn = System.Configuration.ConfigurationManager.AppSettings["ConnectionString"]; private void frmMain_Load(object sender, EventArgs e) { LoadGroup(); if (trvGroup.Nodes.Count > 0) { trvGroup.SelectedNode = trvGroup.Nodes[0]; LoadList(); } else { lvContact.Clear(); } } private void LoadGroup() { try { trvGroup.Nodes.Clear(); SqlConnection conn = new SqlConnection(strConn); SqlCommand cmd = new SqlCommand(); cmd.Connection = conn; cmd.CommandText = "select distinct 组别 from 联系人 where 用户名='"+tsslUserName.Text+"'"; conn.Open(); SqlDataReader sdr = cmd.ExecuteReader(); while (sdr.Read()) { trvGroup.Nodes.Add(sdr[0].ToString()); } sdr.Close(); conn.Close(); } catch { } } private void LoadList() { if (trvGroup.Nodes.Count == 0) { lvContact.Clear(); return; } if (trvGroup.SelectedNode.Index >= 0) { string strGroup = trvGroup.SelectedNode.Text; try { lvContact.Clear(); lvContact.Columns.Add("姓名",100); lvContact.Columns.Add("工作