mainform.cs

一个简短的通信程序

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 Contact
{
    public partial class MainForm : Form
    {

        string connStr = "Data Source = (local);Initial Catalog = contact;user id = sa;password = 1234";
        private bool isAdd;
        private int Fid;

        public MainForm()
        {
            InitializeComponent();
        }

        private void MainForm_Load(object sender, EventArgs e)
        {
            this.getInfo();
        }

        /// <summary>
        /// 从数据库加载所有好友信息
        /// </summary>
        private void getInfo()
        {
            string sql = "select Fid,Fname,Fphone,Faddress from friend";
            SqlConnection conn = new SqlConnection(connStr);
            conn.Open();
            SqlCommand cmd = new SqlCommand(sql, conn);
            SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);

            try
            {
                this.listView.Items.Clear();
                while (reader.Read())
                {
                    string[] subItems = new string[]
					{
						reader.GetInt32(0).ToString(),
						reader.GetString(1),
						reader.GetString(2),
						reader.GetString(3)
					};
                    this.listView.Items.Add(new ListViewItem(subItems));
                }
                reader.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }

        /// <summary>
        /// 取得选中联系人的ID
        /// </summary>
        /// <returns></returns>
        private int getSelectID()
        {
            int result;
            if (this.listView.SelectedItems.Count == 0)
            {
                result = 0;
            }
            else
            {
                ListViewItem temp = this.listView.SelectedItems[this.listView.SelectedItems.Count - 1];
                result = Convert.ToInt32(temp.SubItems[0].Text);
            }
            return result;
        }

        /// <summary>
        /// 使相关控件启用
        /// </summary>
        private void enableInfo()
        {
            this.clearInfo();
            this.txtAddress.Enabled = true;
            this.txtName.Enabled = true;
            this.txtPhone.Enabled = true;
            this.btnOK.Enabled = true;
            this.btnRE.Enabled = true;
            this.txtName.Focus();
        }

        /// <summary>
        /// 修改相关控件状态
        /// </summary>
        private void disableInfo()
        {
            this.clearInfo();
            this.txtAddress.Enabled = false;
            this.txtName.Enabled = false;
            this.txtPhone.Enabled = false;
            this.btnOK.Enabled = false;
            this.btnRE.Enabled = false;
            this.btnAdd.Enabled = true;
            this.btnDel.Enabled = true;
            this.btnEdit.Enabled = true;
        }

        private void clearInfo()
        {
            this.txtName.Text = "";
            this.txtPhone.Text = "";
            this.txtAddress.Text = "";
        }

        /// <summary>
        /// 添加新联系人
        /// </summary>
        /// <param name="_name">姓名</param>
        /// <param name="_phone">电话</param>
        /// <param name="_address">地址</param>
        public void addInfo(string _name, string _phone, string _address)
        {
            //可以使用Command Parameter来构造sql语句以获得更好的效率和更高的安全性
            string sql = "insert into friend (Fname,Fphone,Faddress) values ('";
            sql += _name + "','" + _phone + "','" + _address + "')";
            SqlConnection conn = new SqlConnection(connStr);
            SqlCommand cmd = new SqlCommand(sql, conn);
            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();
        }

        /// <summary>
        /// 修改联系人信息
        /// </summary>
        /// <param name="_id">需要修改的联系人的id</param>
        /// <param name="_name"></param>
        /// <param name="_phone"></param>
        /// <param name="_address"></param>
        public void changeInfo(int _id, string _name, string _phone, string _address)
        {
            string sql = "update friend set Fname = '" + _name + "',Fphone = '" + _phone + "',Faddress = '" + _address + "'";
            sql += " where Fid = " + _id;
            SqlConnection conn = new SqlConnection(connStr);
            SqlCommand cmd = new SqlCommand(sql, conn);
            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            this.enableInfo();
            this.btnEdit.Enabled = false;
            this.btnDel.Enabled = false;
            this.isAdd = true;
        }

        private void btnEdit_Click(object sender, EventArgs e)
        {
            if (this.listView.SelectedItems.Count == 0)
            {
                MessageBox.Show("请点击选择需要修改的联系人！");
                return;
            }
            this.enableInfo();
            ListViewItem lvi = this.listView.SelectedItems[this.listView.SelectedItems.Count - 1];
            this.txtName.Text = lvi.SubItems[1].Text;
            this.txtPhone.Text = lvi.SubItems[2].Text;
            this.txtAddress.Text = lvi.SubItems[3].Text;
            Fid = Convert.ToInt32(lvi.SubItems[0].Text);
            this.isAdd = false;
            this.btnDel.Enabled = false;
            this.btnAdd.Enabled = false;
        }

        private void btnDel_Click(object sender, EventArgs e)
        {
            int infoID = this.getSelectID();

            if (infoID == 0)
            {
                MessageBox.Show("请选中信息先！");
                return;
            }

            try
            {
                string sql = "delete friend where Fid = " + infoID;
                SqlConnection conn = new SqlConnection(connStr);
                conn.Open();
                SqlCommand cmd = new SqlCommand(sql, conn);
                cmd.ExecuteNonQuery();
                conn.Close();
                this.getInfo();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void btnAbout_Click(object sender, EventArgs e)
        {
            MessageBox.Show("联系人程序，用于文章演示。\nCopyRight 某某某", "演示程序", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }

        private void btnRE_Click(object sender, EventArgs e)
        {
            this.disableInfo();
        }

        private void btnOK_Click(object sender, EventArgs e)
        {
            //在执行下面的操作之前你可以对用户提交的信息进行合法验证
            //不合法的数据应该拒绝操作
            if (this.isAdd)
            {
                try
                {
                    addInfo(this.txtName.Text, this.txtPhone.Text, this.txtAddress.Text);
                    MessageBox.Show("成功添加联系人。");
                    this.getInfo();
                    this.disableInfo();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
            else
            {
                try
                {
                    changeInfo(Fid, this.txtName.Text, this.txtPhone.Text, this.txtAddress.Text);
                    MessageBox.Show("成功修改联系人信息。");
                    this.getInfo();
                    this.disableInfo();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
        }
    }
}