Errors made during routine development

 

Note:

This articleArticleI will record the mistakes I made in my personal development and write them out for criticism. I also hope that you will not make any mistakes I have made in the future.

You are welcome to publish your classic questions in the comments. I will update them in the article and enter your name.

 

I. string processing problems:

When a string is intercepted, an error may occur if you do not pay attention to it.

Example 1

If the category contains mens, gender is assigned male. If womens exists, gender is assigned female.

ErrorCodeAs follows:

View code

 1      //  This will never determine female, Because womens contains mens,
  2     //  At that time, it was miserable to be tested by mm. No more correct code, yesProgramAll members can be written. Be careful!  
  3       If  (Gender  =     ""     &&  Category. tolower (). indexof (  "  Mens "  )  >     -  1  )
  4   {
  5   Gender  =     "  Male  "  ;
  6  }
  7     Else     If  (Gender  =     ""     &&  Category. tolower (). indexof (  "  Womens  "  ) >     -  1  )
  8   {
  9   Gender  =     "  Female  "  ;
  10   } 

Example 2

Suppose we have 1 to 300 sites to manage, and now we need to process XXX If it is site 151, 152, 153, 154 and 155.

The error code is as follows:

View code

 1     //  As we all know that the regular expression processing efficiency is not high, this code will be called for hundreds of thousands of times, so string processing is used.
  2     //  However, at that time, we didn't take into account 1 and 51. During the test, we won't test site 1 and 51 due to this change, and almost had an online bug,
  3     // I also let the test mm crazy once, but this is indeed my own fault, there is nothing so angry, please be careful later.  
  4       If  (  "  151,152,153,154,155,  "  . Indexof (ddlcompany. selectedvalue  +  "  ,  "  )  >- 1  )
  5   {....}
  6     //  The correct code is as follows:  
  7       If  (  "  , 151,152,153,154,155,  " . Indexof (  "  ,  "  +  Ddlcompany. selectedvalue  +  "  ,  "  )  >-  1  )
  8   {....} 

Example 3

When dealing with null strings:

View code

 1      //  This mistake is an idiot, but I still made it. I almost encountered a big problem. The more I am a programmer, the more I am an idiot.  
  2       String  Username  =     Null  ;
  3    If  (  String  . Isnullorempty (username. Trim ()))  //  I want to remove a string of spaces.  
  4     {
  5   ...
  6   }
  7    //  Correct code  
  8       If  (  String  . Isnullorempty (username)  |  Username. Trim ()  =  ""  )
  9  {
  10   ...
  11   } 

Ii. Date Error

The time difference between the recent project calculation is calculated in C # and SQL respectively,

C #: (time 1-time 2). Days

SQL: diffdate (D, time 2, time 3)

As a result, the number of days is different. At that time, the self-test was not strong enough and I did not notice it. In the original SQL statement, 23:59:59 to, the result is 0 days.

But 23:59:59 to is a day... d represents only days to subtract, dizzy to death...

Improvement: refined to minute diffdate (MI, time 2, time 3)/1440
 

Iii. F5 and CTRL + F5

when studying CLR memory processing today, I saw an online article saying that you only need to add [loaderoptimization (loaderoptimization. multidomain)] you can add the self-written assembly to the shared domain, just like an int. I tried according to the method, but I finally asked the blogger, he said press Ctrl + F5, and I tried it. Later, I checked it online. Many of my friends said that F5 could not recognize []. I don't know why, but F5 could not recognize, in future debugging, pay attention to Ctrl + F5 (start directly without debugging). It is possible that the debugging has passed, but there is a problem with direct running.