C# 职员管理系统

C#开发的职员管理系统，完成好久了。前几天一人问起找到了这个代码，很适合新手研习。其实改改也能做个毕设了

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

namespace StaffManagement
{
    class DBhelper
    {
        static string strConn = “Provider=Microsoft.Jet.OLEDB.4.0;Data Source=StaffManagement.mdb;Persist Security Info=False“;//连接字符串

        /// 

        /// 验证字符串是否整数
        /// 

        /// 要验证的字符串
        /// 
        public static bool IsInt32（string input）
        {
            string regexString = @“^-?\d+$“;

            return Regex.IsMatch（input regexString）;
        }

        /// 

        /// 查询所有数据
        /// 

        public DataSet selectAll（）
        {
            OleDbConnection objConn = new OleDbConnection（strConn）;
            OleDbCommand objcomm = new OleDbCommand（“select * from StaffManagement“ objConn）;

            DataSet ds = new DataSet（）;
            try
            {
                objConn.Open（）;
                OleDbDataAdapter objda = new OleDbDataAdapter（objcomm）;
                objda.Fill（ds）;
            }
            catch （Exception ex）
            {
                throw ex;
            }
            finally
            {
                objConn.Close（）;
            }
            return ds;
        }
        public DataSet selectfree（string strsql）
        {
            OleDbConnection objConn = new OleDbConnection（strConn）;
            OleDbCommand objcomm = new OleDbCommand（strsql objConn）;

            DataSet ds = new DataSet（）;
            try
            {
                objConn.Open（）;
                OleDbDataAdapter objda = new OleDbDataAdapter（objcomm）;
                objda.Fill（ds）;
            }
            catch （Exception ex）
            {
                throw ex;
            }
            finally
            {
                objConn.Close（）;
            }
            return ds;
        }

        /// 

        /// 按条件查找
        /// 

        /// 条件是否为空
        /// 查找字段
        /// 查找值
        /// 
        public DataSet selectOf（bool isnull string str string value）
        {
            string strsql = “select * from StaffManagement “;
            if （!isnull）
                strsql += “where “ + str + “ like ‘%“ + value + “%‘“;
            OleDbConnection objConn = new OleDbConnection（strConn）;
            OleDbCommand objcomm = new OleDbCommand（strsql objConn）;

            DataSet ds = new DataSet（）;
            try
            {
                objConn.Open（）;
                OleDbDataAdapter objda = new OleDbDataAdapter（objcomm）;
                objda.Fill（ds）;
            }
            catch （Exception ex）
            {
                throw ex;
            

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----

     文件      30208  2015-10-16 13:12  StaffManagement\StaffManagement\bin\Debug\StaffManagement.exe

     文件     397312  2015-10-17 17:29  StaffManagement\StaffManagement\bin\Debug\StaffManagement.mdb

     文件      69120  2015-10-16 13:12  StaffManagement\StaffManagement\bin\Debug\StaffManagement.pdb

     文件      11600  2015-10-17 17:30  StaffManagement\StaffManagement\bin\Debug\StaffManagement.vshost.exe

     文件        490  2010-03-17 22:39  StaffManagement\StaffManagement\bin\Debug\StaffManagement.vshost.exe.manifest

     文件       7403  2014-03-07 16:57  StaffManagement\StaffManagement\DBhelper.cs

     文件       5798  2014-03-07 16:57  StaffManagement\StaffManagement\Edit.cs

     文件      19962  2014-03-07 16:25  StaffManagement\StaffManagement\Edit.Designer.cs

     文件       5817  2014-03-07 16:25  StaffManagement\StaffManagement\Edit.resx

     文件        540  2014-03-07 16:52  StaffManagement\StaffManagement\Login.cs

     文件       3419  2014-03-07 16:37  StaffManagement\StaffManagement\Login.Designer.cs

     文件       5990  2014-03-07 16:37  StaffManagement\StaffManagement\Login.resx

     文件       4844  2014-03-07 16:52  StaffManagement\StaffManagement\Main.cs

     文件      14204  2014-03-07 16:35  StaffManagement\StaffManagement\Main.Designer.cs

     文件       8415  2014-03-07 16:35  StaffManagement\StaffManagement\Main.resx

     文件       5420  2015-10-16 15:43  StaffManagement\StaffManagement\obj\x86\Debug\DesignTimeResolveAssemblyReferences.cache

     文件       6329  2015-10-17 17:29  StaffManagement\StaffManagement\obj\x86\Debug\DesignTimeResolveAssemblyReferencesInput.cache

     文件       1494  2014-03-07 16:37  StaffManagement\StaffManagement\obj\x86\Debug\GenerateResource.read.1.tlog

     文件       3378  2014-03-07 16:37  StaffManagement\StaffManagement\obj\x86\Debug\GenerateResource.write.1.tlog

     文件       7875  2014-03-07 10:18  StaffManagement\StaffManagement\obj\x86\Debug\ResolveAssemblyReference.cache

     文件       3642  2015-10-17 17:30  StaffManagement\StaffManagement\obj\x86\Debug\StaffManagement.csproj.FileListAbsolute.txt

     文件       1089  2015-10-17 10:33  StaffManagement\StaffManagement\obj\x86\Debug\StaffManagement.csproj.GenerateResource.Cache

     文件       9214  2015-10-17 10:33  StaffManagement\StaffManagement\obj\x86\Debug\StaffManagement.csprojResolveAssemblyReference.cache

     文件        180  2015-10-16 13:12  StaffManagement\StaffManagement\obj\x86\Debug\StaffManagement.Edit.resources

     文件      30208  2015-10-16 13:12  StaffManagement\StaffManagement\obj\x86\Debug\StaffManagement.exe

     文件        180  2015-10-16 13:12  StaffManagement\StaffManagement\obj\x86\Debug\StaffManagement.Login.resources

     文件        180  2015-10-16 13:12  StaffManagement\StaffManagement\obj\x86\Debug\StaffManagement.Main.resources

     文件      69120  2015-10-16 13:12  StaffManagement\StaffManagement\obj\x86\Debug\StaffManagement.pdb

     文件        180  2015-10-16 13:12  StaffManagement\StaffManagement\obj\x86\Debug\StaffManagement.Properties.Resources.resources

     文件       4608  2014-03-07 10:10  StaffManagement\StaffManagement\obj\x86\Debug\TempPE\Properties.Resources1.Designer.cs.dll

............此处省略25个文件信息