AccessHelper.cs

最新推荐文章于 2019-11-22 14:06:02 发布

原创最新推荐文章于 2019-11-22 14:06:02 发布 · 553 阅读

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本文介绍了一个用于操作Access数据库的辅助类库，包括连接测试、获取字段名称及查询数据等功能。通过示例代码展示了如何使用该类库进行基本的数据库操作。

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using System;
using System.Collections.Generic;
using System.Data;
using System.Data.OleDb;
using System.Text;

namespace ExtraLib.Helper
{
    public static class AccessHelper
    {
        public static StringBuilder ErrLog = new StringBuilder();

        static void LogClear()
        {
            ErrLog.Length = 0;
        }

        static void Log(string msg)
        {
            ErrLog.AppendLine(msg);
        }

        /// <summary>
        /// 连接测试
        /// </summary>
        /// <param name="connectionString"></param>
        /// <returns></returns>
        public static bool ConnectionTest(string connectionString)
        {
            bool res;
            try
            {
                var conn = new OleDbConnection(connectionString);
                conn.Open();
                res = conn.State == ConnectionState.Open;
                conn.Close();
            }
            catch
            {
                res = false;
            }
            return res;
        }

        /// <summary>
        /// 获取查询字段名
        /// </summary>
        /// <param name="connectionString"></param>
        /// <param name="commandText"></param>
        /// <returns></returns>
        public static string[] GetFieldsName(string connectionString, string commandText)
        {
            try
            {
                var list = new List<string>();
                using (var conn = new OleDbConnection(connectionString))
                {
                    conn.Open();
                    using (var cmd = conn.CreateCommand())
                    {
                        cmd.CommandText = commandText;
                        using (var reader = cmd.ExecuteReader())
                        {
                            if (reader != null && reader.HasRows)
                            {
                                var fieldCount = reader.FieldCount;
                                // 设置列名
                                for (var i = 0; i < fieldCount; i++)
                                {
                                    list.Add(reader.GetName(i));
                                }
                            }
                        }
                        cmd.Dispose();
                    }
                    conn.Close();
                }
                LogClear();
                return list.ToArray();
            }
            catch (Exception ex)
            {
                Log(ex.Message);
                return null;
            }
        }

        /// <summary>
        /// 获取查询数据表
        /// </summary>
        /// <param name="connectionString"></param>
        /// <param name="commandText"></param>
        /// <returns></returns>
        public static DataTable GetTable(string connectionString, string commandText, string[] fieldNames = null)
        {
            try
            {
                var dt = new DataTable();
                using (var conn = new OleDbConnection(connectionString))
                {
                    conn.Open();
                    using (var cmd = conn.CreateCommand())
                    {
                        cmd.CommandText = commandText;
                        using (var reader = cmd.ExecuteReader())
                        {
                            if (reader != null && reader.HasRows)
                            {
                                var fieldCount = reader.FieldCount;
                                // 设置列名
                                var useCustomName = fieldNames != null && fieldNames.Length == fieldCount;
                                for (var i = 0; i < fieldCount; i++)
                                {
                                    dt.Columns.Add(useCustomName ? fieldNames[i] : reader.GetName(i));
                                }
                                // 读行数据
                                while (reader.Read())
                                {
                                    var row = dt.NewRow();
                                    for (var i = 0; i < fieldCount; i++)
                                    {
                                        row[i] = reader[i];
                                    }
                                    dt.Rows.Add(row);
                                }
                            }
                        }
                        cmd.Dispose();
                    }
                    conn.Close();
                }
                LogClear();
                return dt;
            }
            catch (Exception ex)
            {
                Log(ex.Message);
                return null;
            }
        }

    }
}