TypeError: Cannot read property 'XXX' of undefined in Vue development, what are the solutions?

Create a theme switching component, use the checkbox to bind the isDarkMode state and call the toggleTheme function; 2. Check localStorage and system preferences in onMounted to initialize the theme; 3. Define the applyTheme function to apply the dark-mode class to the html element to switch styles; 4. Use CSS custom properties to define bright and dark variables, and overwrite the default styles through the dark-mode class; 5. Introduce the ThemeSwitcher component into the main application template to display the toggle button; 6. Optionally listen to prefers-color-scheme changes to synchronize the system theme. This solution uses Vue

Wireless network displays that it is connected but cannot access the Internet is a problem that many people often encounter when using electronic devices. Although the Wi-Fi signal is full, but the web page cannot be opened or video cannot be viewed. What is the problem? Don't worry, Driver will organize a complete set of troubleshooting and solutions for you today to help you quickly restore network connections. Let's learn about it together~1. A router or router that has abnormally running for a long time may have a performance degradation due to heat, cache accumulation or system failure; if Lightmaster loses communication with the operator's server, even if the device shows that it is connected to Wi-Fi, it will not be able to access the Internet. 1. Restart the network device: Unplug the router and the optical cat, wait for about 30 seconds before powering on and starting again, so that the device can re-establish the connection. 2. Check the settings

When opening the software or game, a prompt suddenly appears that "the application cannot start normally (0xc0000906)" appears, and many users will be confused and don't know where to start. In fact, most of these errors are caused by corruption of system files or missing runtime libraries. Don't rush to reinstall the system. This article provides you with several simple and effective solutions to help you quickly restore the program to run. 1. What is the error of 0xc0000906? Error code 0xc0000906 is a common startup exception in Windows systems, which usually means that the program cannot load the necessary system components or running environment when running. This problem often occurs when running large software or games. The main reasons may include: the necessary runtime library is not installed or damaged. The software installation package is endless

Common reasons for the computer's black screen but still running include driver problems, hardware connection failure or graphics card damage. The solutions are forced to restart, check the monitor connection, try different monitors or ports, update or roll back the graphics card driver, enter safe mode to troubleshoot software conflicts, check hardware such as graphics card and memory, confirm that the BIOS is set correctly, and restore the system if necessary; if you want to distinguish software and hardware problems, you can test in safe mode, observe the startup process, use diagnostic tools, replace the hardware, and listen to abnormal sounds of the computer; to prevent recurrence, keep the driver updated, install genuine software, regularly maintain the system, pay attention to the stability of heat dissipation and power supply, avoid overclocking, regularly backup data, and monitor hardware temperature.

Create the Modal.vue component, use the Composition API to define the props that receive modelValue and title, and use emit to trigger the update:modelValue event to achieve v-model bidirectional binding; 2. Use slot to distribute content in the template, supporting the default slot and named slot header and footer; 3. Use @click.self to close the pop-up window by clicking the mask layer; 4. Import the Modal in the parent component and use ref to control the display and hide it, and use it in combination with v-model; 5. Optional enhancements include listening to the Escape key close, adding transition animation and focus lock. This modal box component has good

Laptop silent? Easy troubleshooting and solving! Laptops are a must-have tool for daily work and study, but sometimes they encounter silent troubles. This article will analyze in detail the common causes and solutions for laptop silence. Method 1: Check the volume and audio equipment connection First, check whether the system volume setting is normal. Step 1: Click the taskbar volume icon to confirm that the volume slider is not muted and the volume is appropriate. Step 2: In the volume control panel, check the "Main Volume" and "Microphone" volume settings to ensure that the volume of all applications has been adjusted correctly. Step 3: If you are using headphones or external speakers, please check that the device is correctly connected and turned on. Method 2: Update or reset audio that is outdated or damaged by the audio driver

The iPad suddenly silent? Don’t panic! This guide will take you to troubleshoot various reasons for iPad silence and provide corresponding solutions to help you quickly recover your sound! There are many reasons why iPads are silent, such as excessive temperatures, system failures, headphone connection problems, etc. Let's check step by step: 1. Check the audio source First, confirm whether the silence is the iPad itself, or the connected headphones or Bluetooth device. If the external device is silent, try reconnecting or restarting the device. If the iPad itself is silent, please continue to the following steps. 2. Check the volume and mute setting. The iPad may be silent because the volume is accidentally turned down or mute on. Please try: Press and hold the volume increase key to check whether the volume has been set to the lowest level. Check if the iPad is located

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