//旧用法:string.Format("{0},{1}",变量1,变量2)实现格式化输出 public void OldMethod() { Student objStudent = new NewDemo.Student(); string s1 = string.Format("{0},{1}", objStudent.Name, objStudent.Age); string s2 = string.Format("姓名={0},年龄={1}", objStudent.Name, objStudent.Age); Console.WriteLine("{0},\r\n{1}", s1, s2); Console.WriteLine(); string s3 = string.Format("{0,10},{1:d3}", objStudent.Name, objStudent.Age); string s4 = string.Format("{0,10},{1,10:d3}", objStudent.Name, objStudent.Age); Console.WriteLine("{0},\r\n{1}", s3, s4); Console.WriteLine(); string s5 = string.Format("{0:yyyy-MM-dd}", DateTime.Now); Console.WriteLine(s5); Console.WriteLine(); string sql = "select Name from Students where StudentId={0} and Age>{1}"; Console.WriteLine(sql, objStudent.StudentId, objStudent.Age); }
//新用法:在字符串前面添加“$”前缀,(变量可以直接写到{}内,并且有很强的智能提示) public void NewMethod() { Student objStudent = new NewDemo.Student(); string s1 = $"{objStudent.Name },{objStudent.Age }"; string s2 = $"姓名={objStudent.Name },年龄={objStudent.Age }"; Console.WriteLine($"{ s1} ,\r\n{ s2} "); string s3 = $"{objStudent.Name,10},{objStudent.Age:d3}"; string s4 = $"{objStudent.Name,10},{objStudent.Age,10:d3}"; Console.WriteLine($"{ s3} ,\r\n{ s4} "); string s5 = $"{DateTime.Now:yyyy-MM-dd}"; Console.WriteLine(s5); //典型应用 string sql = $"select Name from Students where StudentId={objStudent.StudentId} and Age>{objStudent.Age }"; Console.WriteLine(sql); }