DA0010: Expensive GetHashCode
Note
This article applies to Visual Studio 2015. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here
For the latest documentation on Visual Studio, see DA0010: Expensive GetHashCode.
| Item | Value |
|---|---|
| Rule Id | DA0010 |
| Category | .NET Framework Usage |
| Profiling methods | Sampling .NET Memory |
| Message | GetHashCode functions should be cheap and not allocate any memory. Reduce complexity of hash code function if possible. |
| Message type | Warning |
Cause
Calls to the GetHashCode method of the type are a significant proportion of the profiling data or the method allocates memory.
Rule Description
Hashing is a technique for rapidly locating a particular item in a large collection. Because hash tables can be very large and have to support high rates of access, hash tables should be extremely efficient. An implication of this requirement is that GetHashCode methods in the .NET Framework should not allocate memory. Allocating memory increases the load on the garbage collector and exposes the method to potential delays if it becomes necessary to run garbage collection as a result of the allocation request.
How to Fix Violations
Reduce the complexity of the method.