1.四舍五入(控制小数点)
输入一个数,点击button 就弹出一个对话框,里面是已经四舍五入好的数字,如12.595 或者 12.6 或者 12.54 或者 12.553 或者 12
输出结果 12.60 12.60 12.54 12.55 12.00
代码:
double txtnum = Convert.ToDouble(this.textBox1.Text);
if (txtnum < 0)
{
txtnum = Math.Round(txtnum + 5 / Math.Pow(10, 3), 2, MidpointRounding.AwayFromZero);
}
else
{
txtnum = Math.Round(Convert.ToDouble(txtnum), 2, MidpointRounding.AwayFromZero);
}
MessageBox.Show(txtnum.ToString());
2.c# 查找一个字符串在另一个字符串出现的次数]的巧妙做法
string test = "good good study day day up";
string r = test.Replace("oo","");
int num = (test.Length - r.Length) /2;
Response.Write(num);//num为"oo"在test字符串中出现的次数
3.让sql语句查询结果不默认排序,按照in语句的顺序返回结果
例:select productId,shop_type from T_Info_Product where productId in(83,56,14,13,11) and product_status=1 Order by CharIndex( cast(productId as nvarchar(30)),'83,56,14,13,11')