C#MemoryCache判断key是否存在
时间: 2023-11-23 09:12:07 浏览: 54
可以使用MemoryCache的Contains方法来判断指定的key是否存在于缓存中,示例代码如下:
```csharp
MemoryCache cache = MemoryCache.Default;
string key = "myKey";
if (cache.Contains(key))
{
// key存在于缓存中
}
else
{
// key不存在于缓存中
}
```
需要注意的是,Contains方法只能判断缓存中是否存在指定的key,但不能判断该key对应的value是否为null。如果需要判断value是否为null,可以通过Get方法获取key对应的value,并判断是否为null。
相关问题
C# memorycache
C# MemoryCache is a caching mechanism provided by the .NET Framework that allows developers to store data in memory for faster access. It is a key-value store where data is stored as key-value pairs and can be accessed using the key.
MemoryCache is designed to be used in applications that require frequent access to data, such as web applications that need to retrieve data from a database repeatedly. By storing frequently accessed data in MemoryCache, you can reduce the number of database calls and improve the performance of your application.
MemoryCache provides several features, such as time-based expiration, sliding expiration, and the ability to remove items from the cache manually. It also provides thread-safe operations to prevent race conditions when multiple threads access the cache simultaneously.
To use MemoryCache in your C# application, you can create an instance of the MemoryCache class and add items to the cache using the Add method. You can also retrieve items from the cache using the Get method and remove items from the cache using the Remove method.
Here's an example of how to use MemoryCache in C#:
```
// Create a new instance of the MemoryCache class
MemoryCache cache = MemoryCache.Default;
// Add an item to the cache with a key of "myKey" and a value of "myValue"
cache.Add("myKey", "myValue", DateTimeOffset.Now.AddMinutes(5));
// Retrieve the value of the item with a key of "myKey"
string value = cache.Get("myKey") as string;
// Remove the item from the cache with a key of "myKey"
cache.Remove("myKey");
```
Overall, MemoryCache is a powerful tool for improving the performance of your C# applications by reducing the number of database calls and providing faster access to frequently accessed data.
c# memorycache
c是英文中的一个字母,它代表的是英语字母表中的第三个字母。在英文中,字母c的发音是/k/,类似于汉语中的"克"的音。
除了作为字母,c还有其他的用途。例如,它可以表示摄氏度(centigrade)的缩写,用于表达温度。在国际单位制中,摄氏度是温度的单位,以水的结冰点(0°C)和沸腾点(100°C)为标准。而华氏度则是以水的结冰点(32°F)和沸腾点(212°F)为标准。
另外,c还是一个常见的符号,用于表示速度的单位-光速。光速是物理学中的一个重要概念,它是光在真空中的传播速度,约为每秒299792458米。光速是宇宙中最快的速度,无法被任何物体超越。
此外,c还可以代表一些名词,如"城市"(city)和"中心"(center)。在英语中,这些词常常以c开头,用于描述人类活动的中心地带或者具有重要地位的地方。
总而言之,c是英文中的一个字母,在汉语中没有特殊含义,它可以表示英语字母表中的第三个字母,摄氏度,光速,以及一些名词如城市和中心。