ExternalException: A generic error occurred in GDI .
System.Reflection.TargetInvocationException
HResult=0x80131604
Message=Exception has been thrown by the target of an invocation.
Source=mscorlib
StackTrace:
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
at System.Delegate.DynamicInvokeImpl(Object[] args)
at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme)
at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme)
at System.Windows.Forms.Control.InvokeMarshaledCallbacks()
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
at Extract.Program.Main() in D:\Csharp Projects\Extract\Program.cs:line 19
This exception was originally thrown at this call stack:
System.Drawing.Image.Save(string, System.Drawing.Imaging.ImageCodecInfo, System.Drawing.Imaging.EncoderParameters)
System.Drawing.Image.Save(string, System.Drawing.Imaging.ImageFormat)
Extract.Form1.DownloadAsync() in Form1.cs
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(System.Threading.Tasks.Task)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task)
System.Runtime.CompilerServices.TaskAwaiter.GetResult()
Extract.Form1.DownloadImages() in Form1.cs
System.Runtime.CompilerServices.AsyncMethodBuilderCore.ThrowAsync.AnonymousMethod__6_0(object)
Inner Exception 1:
ExternalException: A generic error occurred in GDI .
串列影像和日期都包含 23 個專案。例外不是超出索引，而是在最后一項 23 上拋出例外。它在所有影像上繪制文本，但在專案 23 的回圈結束時它拋出例外。
if (images.Length > 0)
{
for (int i = 0; i < images.Length; i )
{
drawOnImage.DrawText(dates[i].ToString("ddd, dd MMM yyy HH':'mm"), images[i]);
}
}
也許是因為兩個串列包含相同數量的專案 23 ？那我該怎么解決呢？
這是 DownloadAsync 方法的完整代碼，在底部我使用記憶體流和帶有 drawtext 的回圈，并且例外僅在回圈完成時發生在最后一項。
private async Task DownloadAsync()
{
using (var client = new WebClient())
{
client.DownloadFileCompleted = (s, e) =>
{
if (e.Error == null)
{
urlsCounter--;
var t = urls;
if (urlsCounter == 0)
{
CheckIfImagesExist();
btnRadarPath.Enabled = true;
btnSatellitePath.Enabled = true;
radCounter = 0;
satCounter = 0;
lblStatus.Text = "Completed.";
dates = rad.dates;
var images = System.IO.Directory.GetFiles(radarFolderImagesDownload,
"*.gif", SearchOption.AllDirectories).OrderBy(x => x).ToArray();
Array.Sort(images, new MyComparer(false));
if (images.Length > 0)
{
for (int i = 0; i < images.Length; i )
{
drawOnImage.DrawText(dates[i].ToString("ddd, dd MMM yyy HH':'mm"), images[i]);
}
}
GetImagesFiles();
}
}
else
{
string error = e.Error.ToString();
}
};
client.DownloadDataCompleted = (s, e) =>
{
if (e.Error == null)
{
urlsCounter--;
var t = urls;
if (urlsCounter == 0)
{
CheckIfImagesExist();
btnRadarPath.Enabled = true;
btnSatellitePath.Enabled = true;
radCounter = 0;
satCounter = 0;
lblStatus.Text = "Completed.";
dates = rad.dates;
var images = System.IO.Directory.GetFiles(radarFolderImagesDownload,
"*.gif", SearchOption.AllDirectories).OrderBy(x => x).ToArray();
Array.Sort(images, new MyComparer(false));
if (images.Length > 0)
{
for (int i = 0; i < images.Length; i )
{
drawOnImage.DrawText(dates[i].ToString("ddd, dd MMM yyy HH':'mm"), images[i]);
}
}
GetImagesFiles();
}
}
};
client.DownloadProgressChanged = (s, e) => tracker.SetProgress(e.BytesReceived, e.TotalBytesToReceive);
client.DownloadProgressChanged = (s, e) => lblAmount.Text = tracker.SizeSuffix(e.BytesReceived) "/" tracker.SizeSuffix(e.TotalBytesToReceive);
client.DownloadProgressChanged = (s, e) => lblSpeed.Text = tracker.GetBytesPerSecondString();
client.DownloadProgressChanged = (s, e) => myLong = Convert.ToInt64(client.ResponseHeaders["Content-Length"]);
client.DownloadProgressChanged = (s, e) =>
{
progressBar1.Value = e.ProgressPercentage;
label1.Text = e.ProgressPercentage "%";
};
for (int i = 0; i < urls.Count; i )
{
tracker.NewFile();
if (urls[i].Contains("Radar"))
{
await client.DownloadFileTaskAsync(new Uri(urls[i]), radarFolderImagesDownload "\\image" radCounter ".gif");
radCounter ;
}
else
{
lblStatus.Text = "Downloading satellite";
using (MemoryStream ms = new MemoryStream(await client.DownloadDataTaskAsync(new Uri(urls[i]))))
{
Image img = Image.FromStream(ms, true);
img.Save(satelliteFolderImagesDownload "\\image" satCounter ".gif", System.Drawing.Imaging.ImageFormat.Gif);
}
satCounter ;
}
}
}
}
uj5u.com熱心網友回復：
猜測這是在與主執行緒不同的執行緒中發生的。如果是這樣，您需要呼叫 UI 呼叫 (DrawText)。為此，您可以將 Invoke 與委托一起使用。為了更徹底，您可以檢查InvokeRequired是否確實需要呼叫該呼叫（即您在不同的執行緒上）。
Invoke(new Action(() =>
{
drawOnImage.DrawText(dates[i].ToString("ddd, dd MMM yyy HH':'mm"), images[i]);
}));
轉載請註明出處，本文鏈接：https://www.uj5u.com/houduan/347994.html