using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.IO;

public partial class musicChange : System.Web.UI.Page
{
    //定义一个table容器
    public Hashtable typeindex;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            db_music();
        }
        //初始化并添加数据
        typeindex = new Hashtable();
        typeindex["流行"] = 0;
        typeindex["经典"] = 1;
        typeindex["日韩"] = 2;
        typeindex["欧美"] = 3;
        typeindex["其它"] = 4;
    }
    //删除按钮绑定事件
    protected void dg_DeleteCommand(object source, DataGridCommandEventArgs e)
    {
        //dg.Attributes["OnClick"] = "return confirm('你确认要删除吗？')";
        //初始化一个数据库连接对象
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["LocalSqlServer"].ToString());
        //记录当前要删除的歌曲的ID
        string id = dg.DataKeys[e.Item.ItemIndex].ToString();
        //打开这个连接数据库
        conn.Open();
        //初始化一个数据库实务
        SqlTransaction myTrans = conn.BeginTransaction();
        try
        {
            SqlCommand cmd = new SqlCommand();
            cmd.Transaction = myTrans;
            cmd.CommandText = "select * from [music] where id=@id";
            cmd.Connection = conn;
            cmd.Parameters.Add("@id", SqlDbType.NChar).Value = dg.DataKeys[e.Item.ItemIndex].ToString();
            SqlDataReader dr = cmd.ExecuteReader();
            if (dr.Read())
            {
                string musicname = dr.GetString(1);
                string album = dr.GetString(3);
                string singer = dr.GetString(2);
                dr.Close();
                cmd.Parameters.Add("@singer", SqlDbType.NChar).Value = singer;
                cmd.Parameters.Add("@album", SqlDbType.NChar).Value = album;


                cmd.CommandText = "delete from [music] where id = @id";
                cmd.ExecuteNonQuery();

                if (!isExisted("singer", "music", conn, cmd))
                {
                    cmd.CommandText = "delete from [singer] where singer=@singer";
                    cmd.ExecuteNonQuery();
                }

                if (!isExisted("album", "music", conn, cmd))
                {
                    cmd.CommandText = "delete  from [album] where album=@album";
                    cmd.ExecuteNonQuery();
                }

                myTrans.Commit();

                string path = new DirectoryInfo(Server.MapPath("")).FullName.ToString() + @"\file\" + musicname;
                path = path.Replace('\\', '/');
                File.Delete(path);
            }
            db_music();
        }
        catch (Exception ex)
        {
            msg.Text = ex.ToString();
            myTrans.Rollback();
        }
        finally
        {
            conn.Close();
        }
    }

    protected Boolean isExisted(string keyword, string table, SqlConnection con, SqlCommand cmd)
    {
        cmd.CommandText = "select * from [" + table + "] where " + keyword + "=@" + keyword;
        cmd.Connection = con;
        SqlDataReader dr = cmd.ExecuteReader();
        Boolean check = dr.Read();
        dr.Close();
        return check;
    }



    protected void dg_PageIndexChanged(object source, DataGridPageChangedEventArgs e)
    {
        dg.CurrentPageIndex = e.NewPageIndex;
        db_music();
    }

    //页面初始化绑定数据函数
    public void db_music()
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["LocalSqlServer"].ToString());
        try
        {
            msg.Text = "";
            string sqlselect = "SELECT * FROM [music]";

            SqlCommand cmd = new SqlCommand(sqlselect, conn);
            SqlDataAdapter da = new SqlDataAdapter();
            da.SelectCommand = cmd;
            SqlCommandBuilder sqlcb = new SqlCommandBuilder(da);
            DataTable dt = new DataTable();

            da.Fill(dt);
            if (dt.Rows.Count > 0)
            {
                dg.DataSource = dt;
                dg.DataBind();
            }
            else
            {
                msg.Text = "暂时还没有添加歌曲！";
                dg.Visible = false;
            }
            //弹出是否删除框
            for (int i = 0; i < this.dg.Items.Count; i++)
            {
                this.dg.Items[i].Cells[1].Attributes.Add("onclick", "return confirm('确定删除该记录？')");
            }
        }
        catch (Exception ex)
        {
            msg.Text = ex.Message.ToString();
        }
        finally
        {
            conn.Close();
        }
    }
    public int gettype(string type)
    {
        if (typeindex[type] != null)
            return (int)typeindex[type];
        else
            return 0;
    }

}