图形.DrawImage:内存不足异常

本文关键字：异常 内存不足 DrawImage 图形 | 更新日期: 2023-09-27 18:09:40

即使在各种网站和论坛上进行了大量研究，我也无法弄清楚为什么我在这里得到内存不足的异常。有人能解释一下这段代码中所有邪恶的根源吗?该异常是由调用Graphics.DrawImage()方法抛出的，第79行。

[HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult EditImage(FileModel model)
    {
        var fileData = new MySite.Models.File(model.FileID, model.ClientID, ConfigurationManager.ConnectionStrings["MySite"].ConnectionString).Data;
        Image image = null;
        using (var memStream = new MemoryStream())
        {
            memStream.Write(fileData, 0, fileData.Length);
            image = Image.FromStream(memStream);
        }
        using (var graphics = Graphics.FromImage(image))
        {
            graphics.DrawImage(image, model.x1, model.y1, (model.x2 - model.x1), (model.y2 - model.y1));
            graphics.Save();
        }
        using (var memStream = new MemoryStream())
        {
            image.Save(memStream, System.Drawing.Imaging.ImageFormat.Jpeg);
            return File(memStream.ToArray(), "image/jpeg");
        }
    }

堆栈跟踪:

[OutOfMemoryException: Out of memory.]
System.Drawing.Graphics.CheckErrorStatus(Int32 status) +1143476
System.Drawing.Graphics.DrawImage(Image image, Int32 x, Int32 y, Int32 width, Int32 height) +141
ProPilot.Controllers.DocumentsController.EditImage(FileModel model) in C:'DEV'Web'Controllers'DocumentsController.cs:79
lambda_method(Closure , ControllerBase , Object[] ) +104
System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +14
System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +211
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +27
System.Web.Mvc.Async.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() +28
System.Web.Mvc.Async.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _) +10
System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +48
System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +57
System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +223
System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeActionMethodWithFilters>b__36(IAsyncResult asyncResult) +10
System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +48
System.Web.Mvc.Async.<>c__DisplayClass2a.<BeginInvokeAction>b__20() +24
System.Web.Mvc.Async.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult) +102
System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +43
System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +14
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +57
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +47
System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +25
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +47
System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9629296
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

图形.DrawImage:内存不足异常

@Sayse的评论一针见血

当使用图像。FromStream:

必须在图像的生命周期内保持流打开。

来源:http://msdn.microsoft.com/en-AU/library/93z9ee4x.aspx 

using (var memStream = new MemoryStream())
{
    memStream.Write(fileData, 0, fileData.Length);
    using(Image image = Image.FromStream(memStream))
    {
        using (var graphics = Graphics.FromImage(image))
        {
            graphics.DrawImage(image, model.x1, model.y1, (model.x2 - model.x1), (model.y2 - model.y1));
            graphics.Save();
        }
        using (var outStream = new MemoryStream())
        {
            image.Save(outStream, System.Drawing.Imaging.ImageFormat.Jpeg);
            return File(outStream.ToArray(), "image/jpeg");
        }
    }
}

如果您使用Bitmap或Image类，您将发现几个问题。

如果你用Image.FromFile()加载图像，框架不会在加载图像后关闭文件句柄。该文件保持打开状态，直到垃圾收集器重新收集映像。这是GDI+的一个严重设计错误。当映像已经被读入内存后，没有必要让文件保持打开状态。

所以我试图通过使用Image.FromStream()来解决这个问题。但是这不是解决方案，因为当流被关闭时，对该图像的DrawImage()操作将失败并显示"内存不足"。

所以如果你想从文件中读取位图并且你想确保文件句柄是关闭的你必须使用这样一个丑陋的解决方案:

Bitmap ReadBitmapFromFile(String s_Path)
{
    using (FileStream i_Stream = new FileStream(s_Path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
    {
        using (Bitmap i_Bmp = new Bitmap(i_Stream))
        {
            return new Bitmap(i_Bmp);
        }
    }
}

顺便说一下:Image.Clone()也产生了类似的问题。

代替

Bitmap i_Clone = (Bitmap)i_Bmp.Clone()

我不得不使用:

Bitmap i_Clone = new Bitmap(i_Bmp);
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