有很多关于 SO 的问题感叹 VS2010 可能过于严格地应用代码分析规则 CA2000，但我似乎遇到了应该应用它的情况，但没有应用它。
考虑以下代码：
Image srcImage = Image.FromFile(source);
Bitmap newImage = new Bitmap(newWidth, newHeight);
using (Graphics gr = Graphics.FromImage(newImage))
{
gr.DrawImage(srcImage, new Rectangle(0, 0, newWidth, newHeight));
}
newImage.Save(destination, ImageFormat.Jpeg);
现在，如果我在 Visual Studio 2010 中对此运行代码分析，它会抱怨 newImage 没有被释放（很容易修复，将其放在另一个 using 块中），但它不会抱怨 srcImage （它还有一个我从未调用过的 Dispose() 方法）。有谁知道为什么代码分析在这里不抱怨？
There are a lot of questions on SO lamenting the fact that Code Analysis rule CA2000 is being applied possibly too rigorously by VS2010, but I seem to have run into a case where it should be applied, but isn't.
Consider the following code:
Image srcImage = Image.FromFile(source);
Bitmap newImage = new Bitmap(newWidth, newHeight);
using (Graphics gr = Graphics.FromImage(newImage))
{
gr.DrawImage(srcImage, new Rectangle(0, 0, newWidth, newHeight));
}
newImage.Save(destination, ImageFormat.Jpeg);
Now if I run Code Analysis in Visual Studio 2010 on this, it will complain about newImage not being disposed (easy fix, put it in another using block), but it doesn't complain about srcImage (which also has a Dispose() method that I'm never calling). Does anyone know why Code Analysis doesn't complain here?
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CA2000 和类似/相关的 CA2213 (DisposableFieldsShouldBeDispose) 和 CA1001 (TypesThatOwnDisposableFieldsShouldBeDisposable) 规则对于如何识别一次性的“所有权”相当严格。仅当使用实例构造函数直接在代码中创建实例时，他们才会将您的代码视为一次性实例的所有者。由于您使用 Image.FromFile 创建 srcImage 实例，因此该规则不会将您的代码识别为所有者。
如果您不同意此规则行为，您可能需要在 https://connect.microsoft 上创建错误报告。 com/visualstudio/feedback。 （如果您关心一次性字段规则，您可能需要投票支持现有的 https://connect.microsoft.com/VisualStudio/feedback/details/485291/typesthatowndisposablefieldsshouldbedisposable-rule-ca1001-is-too-permissive建议。）
CA2000 and the similar/related CA2213 (DisposableFieldsShouldBeDisposed) and CA1001 (TypesThatOwnDisposableFieldsShouldBeDisposable) rules are rather strict about how they recognize "ownership" of a disposable. They will only consider your code to be the owner of a disposable instance if an instance constructor is used to create the instance directly in your code. Since you use Image.FromFile to create the instance for srcImage, the rule doesn't recognize your code as the owner.
If you disagree with this rule behaviour, you may want to create a bug report at https://connect.microsoft.com/visualstudio/feedback. (If you care about the disposable field rules, you might want to vote for the existing https://connect.microsoft.com/VisualStudio/feedback/details/485291/typesthatowndisposablefieldsshouldbedisposable-rule-ca1001-is-too-permissive suggestion while you're at it.)
好吧，它也应该“抱怨 srcImage”，但是我猜测它不会抱怨它，因为您将其传递给
DrawImage方法“gr. DrawImage(srcImage, new Rectangle(0, 0, newWidth, newHeight));", 所以要么它不够聪明，知道方法返回后它不会被用于更多操作，要么它假设那你在将被处置的gr实例中使用它。无论如何，您应该对srcImage使用using，就像您对newImage所做的那样，并且不要遵循代码分析。Well it should "complain about srcImage" too, however I guess that it doesn't complain about it because you are passing it to the
DrawImagemethod "gr.DrawImage(srcImage, new Rectangle(0, 0, newWidth, newHeight));", So either it is not smart enough to know that it will not being used for more actions after the method returned, or maybe it assumed that you used it ingrinstance that will be disposed. Anyway you should useusingforsrcImagejust like what you are doing withnewImageand don't follow the Code Analysis on that.