• WPF dev modifies the gridcontrol line background color or font color according to the data


    Add under DXG: tableview: <Style.Triggers> <DataTrigger Binding=”{Binding Path=Yxbz}” Value=”False”> <Setter Property=”Foreground” Value=”Red”/> </DataTrigger> Yxbz means valid flag, bool type. Note: I can’t write like this. This writing method can be used in the DataGrid of WPF. But it doesn’t work in gridcontrol of devaexpress. Finally, I found it on the Internet. It is found that […]

  • C memory management


    1.malloc Function: void * malloc (int n); Meaning: allocate n bytes in heap memory and return void pointer type Return: the first address of the storage space is returned after the allocation is successful; Otherwise, null is returned   2.calloc Function: void * calloc (int n, int size) Meaning: allocate n * size bytes on […]

  • Forward look ahead assertion of regular matching


    (?=p)Match the position in front of the P sub pattern. In other words, there is a position that needs to satisfy the p-sub pattern immediately after it. There is also a scientific name called forward antecedent assertion.Example above: ‘xxx_love_study_js.mp4’.replace(/(?=xxx)/g, ‘❤️’) // ❤️xxx_love_study_js.mp4 (?!p)The reverse meaning of (? = P) can be understood as that all […]

  • String in Java args


    String in Java Args refers to variable parameters, which means that the number of parameters is variable. It is an array. If there are multiple parameters defined in the method, the declaration of variable parameters must be in the last parameter public void methodA(String … args){     System.out.println(args[0]); }   public void methodB(String str, String … args){     System.out.println(args[0]); }   https://www.iteye.com/blog/hellotommy-979441

  • The difference between schemas and models in fastapi


    come fromfastapiDocumentCreate the Pydantic models To avoid confusion between the SQLAlchemy models and the Pydantic models, we will have the file models.py with the SQLAlchemy models, and the file schemas.py with the Pydantic models. These Pydantic models define more or less a “schema” (a valid data shape). So this will help us avoiding confusion while […]

  • Set the prompt text when SSH logs in to the server


    issue.net & motd After a new alicloud machine is opened, the default prompt of SSH in the past is: Welcome to Ubuntu 14.04.4 LTS (GNU/Linux 3.13.0-86-generic x86_64) * Documentation: https://help.ubuntu.com/ Welcome to aliyun Elastic Compute Service! You can add some content. There are two related to it: issue.net : Display a banner message before the […]

  • Operators in Python


    Python operator Arithmetic operator Symbol meaning + plus – reduce * ride / except // to be divisible by % Surplus ** exponentiation = assignment += Add etc -= Subtraction *= Multiply, etc /= Divide and so on //= Division, etc %= Surplus, etc Comparison operation Symbol meaning > greater than >= Greater than or […]

  • Mybatisplus condition constructor querywrapper


    Mybatisplus condition constructor querywrapper Querywrapper: an entity object encapsulates an operation classLambdaquerywrapper: a query wrapper used for lambda syntax Example: QueryWrapper<User> queryWrapper = QueryGenerator.initQueryWrapper(user,null); queryWrapper.eq(“user_name”,user.getUserName()); IPage<User> page = new Page<>(pageNo, pageSize); IPage<User> pageList = userServer.page(page, queryWrapper); Example: protected FrfReptPlan getFrfReptPlan(String contractId,String perdNum,String costType){ return frfReptPlanService.getOne(new LambdaQueryWrapper<FrfReptPlan>() .eq(FrfReptPlan::getFpfContrId, contractId) .eq(FrfReptPlan::getPerdNum, perdNum) .eq(FrfReptPlan::getCostType,costType)); } Common methods: Method […]

  • After writing react for 3 months, what have I learned?


    Original link:React those thingsReact hooks The new environment is transferred from Vue to react technology stack, which is an interesting process. In react, you will see many similarities and differences with Vue. You encounter some doubts in the learning process and make records. How does useref solve the null pointer problem? What is the difference […]

  • Understanding of nginx


    preface Record the configurations I have encountered in my current work. Writing an article is just for convenience, because there is no markdown format for notes. Ha ha Reference demo server { listen 80; listen 443; listen 14000; #Notes notes location /dddd/adar { if ($request_uri ~ “[&\?]max_age=([0-9]+)”) { add_header “Cache-Control” “max-age=$1”; } alias /vdar/wdww/hdtml/rdadar/dddist/; } […]

  • Detailed explanation of Flink taskmanager memory model


    Apache Flink provides an efficient workload on top of the JVM by strictly controlling the memory usage of its components. Although the community strives to provide reasonable default values for all configurations, it cannot be applied to all applications deployed by users on Flink. In order to provide maximum production value to our users, Flink […]

  • Basic operation (file) of CMD (command prompt)


    Open the CMD window. Next, we will introduce how to use CMD to create, delete, modify and view files 1.1 create an empty file using CMD (for better demonstration, disk D is the current path in this paper). The command is as follows: Copy nul xxx.xx (file name) Command details: Copy means copy, nul means […]