数据库共通操作类[C#]

以下是数据库持久性操作共通类。
但问题：1：属于那个包
       2：怎么调用最好？

using System;
using System.Data;
using System.Configuration;
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.Windows.Forms;
using System.Collections.Generic;

///
/// Summary description for DataBaseHandle
///
public class DataBaseHandle
{
    #region ====== Filed & Constructor ======
    //定义SqlConnection对象
    private SqlConnection con;
    ///
    /// 构造方法
    ///
    public DataBaseHandle()
    {

    }

    ///
    /// 检测DB连接成功与否
    ///
    ///
    private bool DBState()
    {
        bool nReturn = false;
        try
        {
            con = new SqlConnection("在此写上你的sql连接string");
            con.Open();
            nReturn = true;
        }
        catch
        {
            con.Close();
            nReturn = false;
        }
        return nReturn;
    }

    #endregion ====== Filed & Constructor ======

    #region ====== Insert ======

    ///
    /// insert方法
    ///
    /// 传入一个Table
    /// 传入要插入的表名
    /// 0:成功
    /// -1:失败
    public int Insert(DataTable datInsert, string strTableName)
    {
        int nReturn = -1;
        if (!DBState() || datInsert == null || datInsert.Rows.Count == 0)
        { return nReturn; } //如果DB连接失败,或没传入要插入的表,则返回-1;
        //拼sql
        string strSql = GetInsertSql(datInsert, strTableName);
        if (string.IsNullOrEmpty(strSql))
        { return nReturn; }

        try
        {
            //用sqlCommand执行sql
            SqlCommand sqlCom = new SqlCommand(strSql, con);
            sqlCom.ExecuteNonQuery();
            nReturn = 0;
        }
        catch (Exception)
        {
            return -1;
        }

        return nReturn;
    }

    ///
    /// 取insert 表拼sql
    ///
    /// 传入的表
    /// 表名
    /// 返回拼好的sql语句
    private string GetInsertSql(DataTable datInsert, string strTableName)
    {
        string strReturnSql = string.Empty;
        string strHead = " Insert into [" + strTableName + "]";
        string strCols = "";
        string strTempCol = string.Empty;
        if (datInsert == null || datInsert.Rows.Count == 0)
        {
            return strReturnSql;
        }
        for (int i = 0; i < datInsert.Columns.Count; i++)
        {
            strTempCol += "," + datInsert.Columns[i].ColumnName.ToString();
        }
        strTempCol = strTempCol.Substring(1);
        strCols = " (" + strTempCol + ") " + " values ";
        //int nRowCount = datInsert.Rows.Count;
        List<string> strArrValues = new List<string>();

        //string[] strArrValues = new string[2] {string.Empty,string.Empty};

        int nReturn = GetInserValue(datInsert, strArrValues);
        if (nReturn == -1) return string.Empty;

        for (int j = 0; j < strArrValues.Count; j++)
        {
            strReturnSql += strHead + strCols + " (" + strArrValues[j] + ") ";
        }
        return strReturnSql;
    }
    ///
    /// 拼insertsql
    ///
    ///
    ///
    /// 0:成功
    /// -1:失败
    private int GetInserValue(DataTable datInsert, List<string> strArrValues)
    {
        if (datInsert == null || datInsert.Rows.Count == 0)
        {
            return -1;
        }
        string strRowValue = string.Empty;
        for (int i = 0; i < datInsert.Rows.Count; i++)
        {
            strRowValue = string.Empty;
            for (int j = 0; j < datInsert.Columns.Count; j++)
            {
                strRowValue += "," + "'" + datInsert.Rows[i][j].ToString() + "'";
            }
            strArrValues.Add(strRowValue.Substring(1));
        }
        return 0;
    }
    #endregion ====== Insert ======

    #region ====== Delete ======
    ///
    /// 删除记录
    ///
    /// 传入sqlPara以防sql注入
    /// 传入sql语句
    /// 布尔值决定是否使用sqlPara
    /// 0:成功
    /// -1:失败
    public int Delete(SqlParameter[] sqlPara, string strAlreadySql, bool bUseCustomSql)
    {
        int nReturn = -1;
        if (!DBState()) //如果DB连接失败,则返回-1;
        { return nReturn; }
        if (bUseCustomSql)
        {
            SqlCommand sqlCom = new SqlCommand(strAlreadySql, con);
            sqlCom.ExecuteNonQuery();
        }
        else
        {
            SqlCommand sqlCommand = new SqlCommand(strAlreadySql, con);
            //把防sql注入的sql变量加入sqlCommand对象
            for (int i = 0; i < sqlPara.Length; i++)
            {
                sqlCommand.Parameters.Add(sqlPara[i]);
            }
            sqlCommand.ExecuteNonQuery();
        }
        return nReturn;
    }

    #endregion ====== Delete ======

    #region ====== Update ======

    ///
    /// 更新记录
    ///
    /// 传入由要更新的字段及值组成的表
    /// 传入表名
    /// 更新条件
    /// 0:成功
    /// -1:失败
    public int Update(DataTable datUpdate, string strTableName, string[] strCondition)
    {
        int nReturn = -1;
        if (!DBState()) //如果DB连接失败,则返回-1;
        { return nReturn; }
        try
        {
            //拼update sql
            string strUpdateSql = GetUpdateSql(datUpdate, strTableName, strCondition);
            if (string.IsNullOrEmpty(strUpdateSql)) { return -1; }
            SqlCommand com = new SqlCommand(strUpdateSql, con);
            com.ExecuteNonQuery();
            nReturn = 0;
        }
        catch (Exception)
        {
            nReturn = -1;
        }
        return nReturn;
    }

    ///
    /// 拼update sql
    ///
    /// 传入要更新的表
    /// 表名
    /// 更新条件,[]对应要更新表的每一行的条件
    /// 返回拼完成的sql
    private string GetUpdateSql(DataTable datUpdate, string strTableName, string[] strCondition)
    {
        string strReturn = string.Empty;
        string strStart = " Update " + strTableName;
        List<string> strSetValues = new List<string>();
        int nReturn = GetSetSql(datUpdate, strSetValues);
        if (nReturn == -1)
        { return string.Empty; }
        for (int i = 0; i < strSetValues.Count; i++)
        {
            strReturn += strStart + strSetValues[i] + strCondition[i];
        }
        return strReturn;
    }

    ///
    /// 拼update sql
    ///
    ///
    ///
    /// 0:成功
    /// -1:失败
    private int GetSetSql(DataTable datUpdate, List<string> strSetValues)
    {
        int nReturn = -1;
        if (datUpdate == null || datUpdate.Rows.Count == 0)
        {
            return -1;
        }
        try
        {
            for (int i = 0; i < datUpdate.Rows.Count; i++)
            {
                string str = string.Empty;
                for (int j = 0; j < datUpdate.Columns.Count; j++)
                {
                    str += " , " + datUpdate.Columns[j].ColumnName + "=" + "'" + datUpdate.Rows[i][j].ToString() + "'" ;
                }
                string strSql = " Set " + "  " + str.Substring(2) + "  ";
                strSetValues.Add(strSql);
            }
            nReturn = 0;
        }
        catch(Exception)
        {
            nReturn = -1;
        }
        return nReturn;
    }
    #endregion ====== Update ======

    #region ====== Search ======

    ///
    /// 查找记录
    ///
    /// 查打到数据用此表回传
    /// 用sql变量防sql注入
    /// 可以传自己写的sql
    /// 布尔值定义是否要用自己写的sql
    /// 0:成功
    /// -1:失败
    public int Search(out DataTable datReturn, SqlParameter[] sqlPara, string strAlreadySql, bool bUseCustomSql)
    {
        datReturn = new DataTable();
        int nReturn = -1;
        if (!DBState()) //如果DB连接失败,则返回-1;
        { return nReturn; }
        try
        {
            if (bUseCustomSql)//如果用自己写的sql
            {
                SqlCommand sqlCom = new SqlCommand(strAlreadySql, con);
                SqlDataAdapter dap = new SqlDataAdapter(sqlCom);
                dap.Fill(datReturn);
                nReturn = 0;
            }
            else  //不用自己写的sql
            {
                SqlCommand sqlCommand = new SqlCommand(strAlreadySql, con);
                for (int i = 0; i < sqlPara.Length; i++)
                {
                    if (sqlPara[i] != null)
                    {
                        sqlCommand.Parameters.Add(sqlPara[i]);
                    }
                }
                //取得数据放在表中.
                SqlDataAdapter sqlDap = new SqlDataAdapter(sqlCommand);
                sqlDap.Fill(datReturn);
                nReturn = 0;
            }
        }
        catch(Exception)
        {
            nReturn = -1;
        }
        return nReturn;
    }

    #endregion ====== Search ======
}