| 方法 | 返回值含义 |
| IsArray(VarName As Object) | 变量是否指向数组 |
| IsDBNull(Expression As Object) | 指示表达式的计算结果是否为System.DBNull类 |
| IsError(Expression As Object) | 指示表达式是否是异常类型 |
| IsNothing(Expression As Object) | 指示表达式是否未被指派对象 |
| IsNumeric(Expression As Object) | 指示表达式的计算结果是否为数字 |
| IsReference(Expression As Object) | 指示表达式是否为引用类型 |
| IsDate(Expression As Object) | 该值指示表达式是否表示一个有效的Date值 |
