正确处理内存流(WPF图像转换)

Question

谁能告诉我如何最好地处理内存流？以前,我有这个,一切正常:

MemoryStream strmImg = new MemoryStream(profileImage.Image);
BitmapImage myBitmapImage = new BitmapImage();
myBitmapImage.BeginInit();
myBitmapImage.StreamSource = strmImg;
myBitmapImage.DecodePixelWidth = 200;
myBitmapImage.DecodePixelWidth = 250;
myBitmapImage.EndInit();
this.DemographicInformation.EmployeeProfileImage = myBitmapImage;

我后来才意识到,由于MemoryStream实现了IDisposable,我将会发生内存泄漏,并且在使用它之后应该将其丢弃,这导致我实现了这个:

using(MemoryStream strmImg = new MemoryStream(profileImage.Image))
{
    BitmapImage myBitmapImage = new BitmapImage();
    myBitmapImage.BeginInit();
    myBitmapImage.StreamSource = strmImg;
    myBitmapImage.DecodePixelWidth = 200;
    myBitmapImage.DecodePixelWidth = 250;
    myBitmapImage.EndInit();
    this.DemographicInformation.EmployeeProfileImage = myBitmapImage;
}

问题出在这行代码中:

 myBitmapImage.StreamSource = strmImg;

我的假设是这是引用内存位置,并且dispose显然清理了该位置,并且它在过去工作,因为它从未正确处理过

我的问题是,如何使用MemoryStream并在使用后正确处理,同时仍然保留我需要的转换数据(图像)？

谢谢,

ROKA

Answer 1

你需要添加这一行:

myBitmapImage.CacheOption = BitmapCacheOption.OnLoad;

在加载时将整个映像缓存到内存中.如果没有此行,则CacheOption属性的默认值OnDemand将保留对流的访问权,直到需要映像为止.所以你的代码应该是:

using(MemoryStream strmImg = new MemoryStream(profileImage.Image))
{
    BitmapImage myBitmapImage = new BitmapImage();
    myBitmapImage.BeginInit();
    myBitmapImage.CacheOption = BitmapCacheOption.OnLoad;
    myBitmapImage.StreamSource = strmImg;
    myBitmapImage.DecodePixelWidth = 200;
    myBitmapImage.DecodePixelWidth = 250;
    myBitmapImage.EndInit();
    this.DemographicInformation.EmployeeProfileImage = myBitmapImage;
}