By value or by instance?

kyno2alex

It is often seen that when inserting data, when using the data processing layer method, many people build a data class in the project. Then before invoking the data processing layer method, instantiate that data class and pay values ​​for the properties inside. Then pass the instance as a parameter to the data processing method?
I would like to ask why is this better than passing each variable directly as a parameter?
Can you talk about the advantages and disadvantages of these two methods of passing parameters?

zhouji700

Because if the reference type is passed directly, it may be modified internally by the method

hopelose

No big difference!

everever30

The advantage of passing objects is to keep the interface uniform. If there is a change, only change it internally instead of changing the interface.

kyno2alex

Because if the reference type is passed directly, it may be modified internally by the method

Can you give an example?
That is to say, if the parameter data is not used after calling the method, are they the same?
So if there are many parameters, such as more than 10 parameters, will there be a difference in efficiency?

kyno2alex

everever30
The advantage of passing objects is to keep the interface uniform. If there is a change, only change it internally instead of changing the interface.

That is to say, is the difference between the two just in writing code?
Is it the same when running the code?

shenmue024

By default in C #, references are passed.

string [] ary = new string [] {"a"};
this.DoChante (ary);
Response.Write (ary [0]);


public void DoChante (string [] a)
{
a [0] = "B";
}

zhouji700

shenmue024has been written, haha.
As for the efficiency, it is definitely worse to pass parameters by instance, but if the code is good enough, it should be ignored, huh.

ooloife

Passing a reference or passing an instance depends on your specific application. Generally, references are passed. One is fast. The other is that you can modify the value of the variable inside the class. If you do not want to modify the original value, you can consider传 Instance.

saintfrosty

By abstracting data operations, you can use them longer and fewer problems, avoiding constant refactoring.

If the 20 subclasses of type A objects are related to the 20 subclasses of type B, 400 types of relationships may need to be defined, and 10 large books need to be written to explain, but if the subclasses inherit the parent class, you do not need to export the subclasses The connection was described piecemeal, and perhaps the agreement was made clear with only two pages of A4 paper.