c#编程实例代码

//massagebox
System.Windows.Forms.MessageBox.Show(“欢迎使用Vsual Studio 2005！”);

//tab顺序
textBox1.TabIndex.ToString( );

//日期与时间方法及属性使用示例
lblInfo.Text += “\n获取当前日期字符串DateTime.Now.ToLongDateString( )：\n” + DateTime.Now.ToLongDateString();
lblInfo.Text += “\n获取当前时间字符串DateTime.Now.ToLongTimeString( )：\n” + DateTime.Now.ToLongTimeString();
lblInfo.Text += “\n获取当前日期字符串(2)DateTime.Now.ToShortDateString( )：\n” + DateTime.Now.ToShortDateString();
lblInfo.Text += “\n获取当前时间字符串(2)DateTime.Now.ToShortTimeString( )：\n” + DateTime.Now.ToShortTimeString();
/*
lblInfo.Text += “\n获取当前年份DateTime.Now.Year：” + DateTime.Now.Year;
lblInfo.Text += “\n获取当前小时DateTime.Now.Hour：” + DateTime.Now.Hour;/
lblInfo.Text += “\n当前为星期几DateTime.Now.DayOfWeek：” + DateTime.Now.DayOfWeek;
lblInfo.Text += “\n当前为一年中的第几天DateTime.Now.DayOfYear：” + DateTime.Now.DayOfYear;
lblInfo.Text += “\n增减天数后的日期DateTime.Now.AddDays(1.5)：” + DateTime.Now.AddDays(1.5);
/
lblInfo.Text += “\n增减天数后的日期DateTime.Now.AddDays(-1.5)：” + DateTime.Now.AddDays(-1.5);*/
//数学方法及字段使用示例
lblInfo.Text += “\n字段，圆周率Math.PI：”
+ Math.PI;
lblInfo.Text += “\n求绝对值方法Math.Abs(-38.5)：” + Math.Abs(-38.5);
lblInfo.Text += “\n求正弦值方法（30度）Math.Sin(Math.PI/6)：” + Math.Sin(Math.PI / 6);
lblInfo.Text += “\n求余弦值方法（60度）Math.Cos(Math.PI/3)：” + Math.Cos(Math.PI / 3);
lblInfo.Text += “\n求正切值方法（45度）Math.Tan(Math.PI/4)：” + Math.Tan(Math.PI / 4);
lblInfo.Text += “\n求最大值方法Math.Max(3,2)：” + Math.Max(3, 2);
lblInfo.Text += “\n求最小值方法Math.Min(3,2)：” + Math.Min(3, 2);
lblInfo.Text += “\n求幂方法（3的平方）Math.Pow(3,2)：” + Math.Pow(3, 2);
lblInfo.Text += “\n求保留小数值方法Math.Round(3.54)：” + Math.Round(3.54);
lblInfo.Text += “\n求保留小数值方法（2）Math.Round(3.1415926,3)："+ Math.Round(3.1415926, 3);
lblInfo.Text += “\n求平方根方法（2的平方根）Math.Sqrt(2)：” + Math.Sqrt(2);

private void btnCalculate_Click(object sender, System.EventArgs e)
{
int Number1,Number2,Number3; //声明三个整型变量
Number1=int.Parse(txtNumber1.Text);
Number2=int.Parse(txtNumber2.Text);
labResult.Text=“计算结果：\n”;
Number3=Number1+Number2;
labResult.Text+=(“两个整数的和为："+Number3+"\n”);
Number3=Number1-Number2;
labResult.Text+=(“两个整数的差为："+Number3+"\n”);
Number3=Number1*Number2;
labResult.Text+=(“两个整数的积为："+Number3+"\n”);
float Number4=(float)Number1/Number2;
labResult.Text+=(“两个整数的商为："+Number4);
}

//字符串方法及属性使用示例
lblInfo.Text += “\n查找指定子串在字符串中的位置"abCDeFg".IndexOf("b",0)：” + “abCDeFg”.IndexOf(“b”, 0);
lblInfo.Text += “\n在指定位置插入子串"abCDeFg".Insert(3,"hij")：” + “abCDeFg”.Insert(3, “hij”);
lblInfo.Text += “\n指定子串最后一次出现的位置"abCDeFg".LastIndexOf("F"))：” + “abCDeFg”.LastIndexOf(“F”);
lblInfo.Text += “\n字符串中的字符数"abCDeFg".Length：” + “abCDeFg”.Length;
lblInfo.Text += “\n移除子串"abCDeFg".Remove(3,2)：” + “abCDeFg”.Remove(3, 2);
lblInfo.Text += “\n替换子串"abCDeFg".Replace("eFg","hij")：” + “abCDeFg”.Replace(“eFg”,“hij”);
lblInfo.Text += “\n截取子串"abCDeFg".Substring(3,4)：” + “abCDeFg”.Substring(3, 4);
lblInfo.Text += “\n字符串转小写"abCDeFg".ToLower( )：” + “abCDeFg”.ToLower();
lblInfo.Text += “\n字符串转大写"abCDeFg".ToUpper( )：” + “abCDeFg”.ToUpper();
//随机数方法使用示例（假设随机对象为rn)
Random rn = new Random();
lblInfo.Text += “\n产生随机整数rn.Next( )：” + rn.Next();
lblInfo.Text += “\n产生0～100之间的随机整数rn.Next(100)：” + rn.Next(100);
lblInfo.Text += “\n产生-100～100之间的随机整数rn.Next(-100, 100)：” + rn.Next(-100, 100);
lblInfo.Text += “\n产生0.0～1.0之间的随机实数rn.NextDouble( )：” + rn.NextDouble();
//文字链接打开
private void lnkOpen_LinkClicked(object sender,System.Windows.Forms.LinkLabelLinkClickedEventArgs e)
{
lnksina.LinkVisited=true;
//添加“using System.Diagnostics;”可以省略System.Diagnostics引导
Process.Start(lnksina.Text.Substring(3,15));
}
//图片框
private void btnShowPic1_Click(object sender, System.EventArgs e)
{
picBrowse.Image=new Bitmap(“001.gif”);
labPicInfo.Text=“当前显示为第一张图片”;
}

private void btnShowPic2_Click(object sender, System.EventArgs e)
{
picBrowse.Image=Image.FromFile(“004.gif”);
labPicInfo.Text=“当前显示为第二张图片”;
}
//形参不改变参数外部值 引用形参加 ref
//静态

//重载(n次声明)
char.Parse(txtL.Text)
double.Parse(txtL.Text)；
int.Parse(txtL.Text);

//构造函数
//多态