***的方法是使用Javascript或ASP在UI中进行所有这些验证。净验证控件，如必需表达式验证控件。

检查以下链接 -

ASP.NET - 验证器 [ ^ ]

使用客户端验证JavaScript [ ^ ]



您可以在属性层中仔细检查这些，如下所示 -

The best way is to do all these validation in the UI using Javascript or ASP.Net validation controls like Required Expression Validation control.
Check following links-
ASP.NET - Validators[^]
Client Side Validation using JavaScript[^]

You can double check these in the Property layer too like following -

string courseNum;
public string CourseNum
{
    get { return courseNum; }
    set {
          if(value==null) throw new ArgumentException("Course Num can't be null.");
          courseNum = value;
        }
}

希望有所帮助：）

Hope it helps :)