{
class Program
{
private static string ConStr = @"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\学习笔记\基础知识\DB.mdf;Integrated Security=True;User Instance=True";
static void Main(string[] args)
{
DataSetTest();
//LinqTest();
Console.ReadLine();
}
#region * ADO.Net
//执行SQL语句
public static void DoSqlCmd(string sCmdText, Dictionary<string, object> dPar)
{
using (SqlConnection con = new SqlConnection(ConStr))
{
con.Open();
using (SqlCommand cmd = new SqlCommand(sCmdText, con))
{
foreach (KeyValuePair<string, object> kvp in dPar)
{
cmd.Parameters.AddWithValue(kvp.Key, kvp.Value);
}
cmd.ExecuteNonQuery();
}
}
}
//
static void DataSetTest()
{
//DataSet离线数据库模型模型
DataSet ds = new DataSet();
DataTable dt = new DataTable();
ds.Tables.Add(dt);
DataColumn dc1 = new DataColumn("UserID", typeof(System.Guid));
DataColumn dc2 = new DataColumn("UserName", typeof(System.String));
dt.Columns.Add(dc1);
dt.Columns.Add(dc2);
dt.PrimaryKey = new DataColumn[] { dc1 };
DataRow dr = dt.NewRow();
dr["UserID"] = Guid.NewGuid();
dr["UserName"] = "a";
dt.Rows.Add(dr);
dt.Reset();//重置
SqlDataAdapter sda = new SqlDataAdapter("select * from tbUserInfo", ConStr);
sda.Fill(dt);
SqlCommand cmd = new SqlCommand("insert into tbUserInfo (UserName, Pwd, AddTime) values (@UserName, @Pwd, @AddTime)");
cmd.Parameters.AddWithValue("@UserName", "ff");
cmd.Parameters.AddWithValue("@Pwd", "ff");
cmd.Parameters.AddWithValue("@AddTime", DateTime.Now);
sda.InsertCommand = cmd;
SqlCommandBuilder scb = new SqlCommandBuilder(sda);
sda.Update(dt);
//列遍历
foreach (DataColumn dc in dt.Columns)
{
Console.WriteLine(dc.ColumnName);
}
//行遍历
foreach (DataRow dr1 in dt.Rows)
{
Console.WriteLine(dr1["UserID"] + " " + dr1["UserName"]);
}
}
#endregion
#region * Linq to SQL为一个ORM框架(对象，关系，映射)
static void LinqTest()
{
DataContext dc = new DataContext(ConStr);
dc.Log = Console.Out;
Table<tbUserInfo> Users = dc.GetTable<tbUserInfo>();//查询所有记录
//var Users = from user in dc.GetTable<tbUserInfo>() where user.UserName == "a" select user;
//添加
tbUserInfo u1 = new tbUserInfo();
u1.UserName = "d";
u1.Pwd = "d";
u1.AddTime = DateTime.Now;
u1.Note = "d";
Users.InsertOnSubmit(u1);
//先查出来再操作
var u2 = (from user in Users where user.UserName == "d" select user).First();
u2.Pwd = "test";//更新
Users.DeleteOnSubmit(u2); //删除
dc.SubmitChanges();//提交更改，类似Dataset
foreach (var user in Users)
{
Console.WriteLine(user.UserID + "****" + user.UserName + user.Pwd + user.AddTime);
}
}
#endregion
}
//Linq采用侵入式映射
[Table(Name = "tbUserInfo")]
public class tbUserInfo
{
[Column(IsPrimaryKey = true, IsDbGenerated = true)]
public Guid UserID { get; set; }
[Column]
public string UserName { get; set; }
[Column]
public string Pwd { get; set; }
[Column]
public DateTime AddTime { get; set; }
[Column]
public string Note { get; set; }
}
}
{
class Program
{
static void Main(string[] args)
{
Son_Class son = new Son_Class();
Console.WriteLine(Son_Class.str);
son.virtualMethod();
son.abstractMethod();
myStruct s1 = new myStruct();//直接调用构造函数，推荐
s1.Call();
myStruct s2;//这种方式必须要给所有参数赋值后才能调用内部方法
s2.Name = "hb";
s2.Call();
TypeChange();
enmu_Test();
Delegate_Test();
Console.Read();
}
static void TypeChange()
{
string str = new string(new char[]{'1','2'});//提倡这样干以充分利用其构造函数，呵呵
int i = int.Parse(str);//各种基类型都提供了parse这个对string转换直通车
int j = Convert.ToInt32(str);//Convert用于各种基类型的强制转换
Console.WriteLine(i.GetType());
Son_Class son = new Son_Class();
if (son is Father_Class)
{
//is用于类型判断，无异常；as先判断然后转换（失败会NullReferenceException）
Father_Class father = son as Father_Class;
father = (Son_Class)son;
}
}
/*
* const = ststic readonly：是编译时常量，只能为基本类型（int，string等）且必需赋初值；readonly：运行时常量，任意类型
* 值类型深拷贝，引用类型用memberwithclone方法浅拷贝（只copy引用地址）
*/
enum Enum_famliy
{
farther = 5,//enum是引用类型，是个抽象类，默认从0开始的常数集合
mother,
me
}
static void enmu_Test()
{
Enum_famliy myFamliy = new Enum_famliy();
foreach(string item in Enum.GetNames(myFamliy.GetType()))
{Console.WriteLine(item);}//
foreach (Enum_famliy item in Enum.GetValues(myFamliy.GetType()))
{ Console.WriteLine(item.ToString("D")); }//获取整数
}
delegate void CountDelegate(int x, int y);//第一步：声明委托
public static void Sum(int x, int y) { Console.WriteLine(x + y); }//第二步：创建关联的方法，同参同返回值
public static void Subtract(int x, int y) { Console.WriteLine(x - y); }
private static CountDelegate Sum_Delegate;//第三步：定义委托类型变量
static void Delegate_Test()
{
Sum_Delegate = new CountDelegate(Subtract);
Sum_Delegate += new CountDelegate(Sum);//委托链
Sum_Delegate(2, 3);
//匿名方法：不知道委托类型变量时只能用匿名方法
//CountDelegate Sum = delegate(int x, int y)//
//{ Console.WriteLine(x + y); };
//Sum(1, 2);
}
}
abstract class Father_Class //抽象类才能有抽象方法
{
public static string str = "static = share,由类访问并被类的所有实例共享，避免冗余，如sqlconstr";
public virtual void virtualMethod()
{ Console.WriteLine("接口用于定义类的能力；抽象类是能提供部分实现的接口，多用于定义属性，如版本控制"); }
public abstract void abstractMethod();
}
class Son_Class : Father_Class
{
public override void virtualMethod()
{ Console.WriteLine("virtualMethod可以自己实现，也可以由子类override"); }
public override void abstractMethod()
{ Console.WriteLine("abstractMethod只能由子类override"); }
}
struct myStruct
{
public string Name;
public void Call() { Console.WriteLine("Struct:值类型意味高效率；仅用于存储数据；仅可继承自接口"); }
}
[Serializable]
public class MyException : Exception, ISerializable
{
//自定义本地文本信息
private string myMsg;
public string MyMsg{get { return myMsg; }}
//重写只读本地文本信息属性
public override string Message
{
get
{
string msgBase = base.Message;
return myMsg == null ? msgBase : msgBase + myMsg;
}
}
//实现基类的3个公有构造函数
public MyException()
: base() { }
public MyException(string message)
: base(message) { }
public MyException(string message, Exception innerException)
: base(message, innerException) { }
//为新增字段实现构造函数
public MyException(string message, string myMsg)
: this(message)
{
this.myMsg = myMsg;
}
public MyException(string message, string myMsg, Exception innerException)
: this(message, innerException)
{
this.myMsg = myMsg;
}
//用于序列化的构造函数，以支持跨应用程序域或远程边界的封送处理
protected MyException(SerializationInfo info, StreamingContext context)
: base(info, context)
{
myMsg = info.GetString("MyMsg");
}
//重写基类GetObjectData方法，实现向SerializationInfo中添加自定义字段信息
public override void GetObjectData(SerializationInfo info, StreamingContext context)
{
info.AddValue("MyMsg", myMsg);
base.GetObjectData(info, context);
}
}
}