用户代码未处理参数 null 异常

Question

I am getting following error.

argument null exception was unhandled by user code. Value cannot be null. Parameter name: value

in the below code at Bold place.

public static void InsertIntoCache(string cacheKey, object value)
{
    HttpRuntime.Cache.Insert(cacheKey, value, null, DateTime.Now.Add(new TimeSpan(0, CacheDuration, 0)), **Cache.NoSlidingExpiration**, CacheItemPriority.Default,null);
}

please help me on this.

Answer 1

The method signature for Cache.Insert() is (taken from MSDN ):

public void Insert (
string key,
Object value,
CacheDependency dependencies,
DateTime absoluteExpiration,
TimeSpan slidingExpiration,
CacheItemPriority priority,
CacheItemRemovedCallback onRemoveCallback
)

The error is telling you that value , which is the 2nd parameter in the .Insert() method, can not be null. That means that your method is being called with null as the 2nd parameter, like:

InsertIntoCache("some_key", null);  // this will throw an exception.

Basically, you can not cache 'null' as a value. If you scroll down in this link to "Exceptions", it states that Insert() will throw a ArgumentNullException when:

The key or value parameter is a null reference