我有一个WPF应用程序，在其中使用SaveFileDialog。 流程如下：
1-用户使用SaveFileDialog选择文件名并关闭对话框
2-应用程序尝试写入文件。
3-尝试写入文件时，如果文件被锁定，则会抛出IOException。
4-如果我再次尝试打开SaveFileDialog，则应用程序崩溃，并在ntdll.dll上显示“堆已损坏”
我找不到解决办法。即使在Try..Catch内部，应用程序也会崩溃。
SaveFileDialog的代码
try{
Dispatcher.BeginInvoke(new Action(() =>
{
SaveFileDialog sfd = new SaveFileDialog();
sfd.Reset();
sfd.AddExtension = true;
sfd.CheckFileExists = false;
sfd.CheckPathExists = true;
sfd.CreatePrompt = false;
sfd.OverwritePrompt = true;
sfd.DefaultExt = defaultExt;
sfd.Filter = filter;
sfd.Title = "Save As " + fileTypeDisplay;
sfd.InitialDirectory = specialFolder;
sfd.FileName = newFileNameNoExt;
sfd.FilterIndex = 1;
if (!string.IsNullOrEmpty(specialFolder))
{
FileDialogCustomPlace cp = new FileDialogCustomPlace(specialFolder); // does not throw exceptions
sfd.CustomPlaces.Add(cp);
}
try
{
if (sfd.ShowDialog(MyMainWindow) == true) //<-- ERROR HERE
{
fileToSave = sfd.FileName;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
sfd = null;
}
})).Wait();
}
catch(exception ex)
{
...log exception...
}
答案 0 :(得分：0)
这不是答案，而是我如何解决崩溃的问题。这是很久以前的遗留代码，线索是崩溃总是发生在异常之后。但是，为什么异常会导致SaveFileDialog问题并导致应用崩溃？
深入学习我所了解的代码，是在用户在SaveFileDialog中选择文件后执行的。
请注意在catch块中对方法 AnotherUserIsLockingPkg 的调用。
当我注释掉对该方法的调用时，对该问题的SaveFileDialog.ShowDialog（）调用停止了，从而使应用程序崩溃。我将尝试遵循其他建议并查看行为。
如果有人对为什么会这样有任何想法，请多加评论。
FileStream strm = null;
try
{
strm = fi.Open(FileMode.Open, forFileAccessMode, fileShare);
}
catch (IOException) // the file is already open
{
...
fiuEx.IsByOtherUser = AnotherUserIsLockingPkg(filePath);
...
}
catch (Exception ex)
{
...
}
finally
{
....
}
下面的代码用于检查文件是否被其他应用程序锁定。它使用一些API调用。看起来这段代码改编自https://stackoverflow.com/a/20623311/3044154
下面列出了方法AnotherUserIsLockingPkg。
#region Check if another user's process is locking a pkg
[StructLayout(LayoutKind.Sequential)]
private struct RM_UNIQUE_PROCESS
{
public int dwProcessId;
public System.Runtime.InteropServices.ComTypes.FILETIME ProcessStartTime;
}
private const int RmRebootReasonNone = 0;
private const int CCH_RM_MAX_APP_NAME = 255;
private const int CCH_RM_MAX_SVC_NAME = 63;
//private enum RM_APP_TYPE
//{
// RmUnknownApp = 0,
// RmMainWindow = 1,
// RmOtherWindow = 2,
// RmService = 3,
// RmExplorer = 4,
// RmConsole = 5,
// RmCritical = 1000
//}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
private struct RM_PROCESS_INFO
{
public RM_UNIQUE_PROCESS Process;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCH_RM_MAX_APP_NAME + 1)]
public string strAppName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCH_RM_MAX_SVC_NAME + 1)]
public string strServiceShortName;
//public RM_APP_TYPE ApplicationType;
public uint AppStatus;
public uint TSSessionId;
[MarshalAs(UnmanagedType.Bool)]
public bool bRestartable;
}
[DllImport("rstrtmgr.dll", CharSet = CharSet.Unicode)]
private static extern int RmRegisterResources(uint pSessionHandle,
UInt32 nFiles,
string[] rgsFilenames,
UInt32 nApplications,
[In] RM_UNIQUE_PROCESS[] rgApplications,
UInt32 nServices,
string[] rgsServiceNames);
[DllImport("rstrtmgr.dll", CharSet = CharSet.Auto)]
private static extern int RmStartSession(out uint pSessionHandle, int dwSessionFlags, string strSessionKey);
[DllImport("rstrtmgr.dll")]
private static extern int RmEndSession(uint pSessionHandle);
[DllImport("rstrtmgr.dll")]
private static extern int RmGetList(uint dwSessionHandle,
out uint pnProcInfoNeeded,
ref uint pnProcInfo,
[In, Out] RM_PROCESS_INFO[] rgAffectedApps,
ref uint lpdwRebootReasons);
/// <summary>
/// Checks if a pkg has been locked by another user
/// </summary>
/// <param name="path">The pkg file path.</param>
/// <param name="includeCurrentUserProcesses">Check also for current user's processes</param>
/// <returns></returns>
public static bool AnotherUserIsLockingPkg(string path, bool includeCurrentUserProcesses = false)
{
uint handle;
string key = Guid.NewGuid().ToString();
Process currentProcess = Process.GetCurrentProcess();
int res = RmStartSession(out handle, 0, key);
if (res != 0)
throw new Exception("Could not begin restart session. Unable to determine file locker.");
try
{
const int ERROR_MORE_DATA = 234;
uint pnProcInfoNeeded = 0,
pnProcInfo = 0,
lpdwRebootReasons = RmRebootReasonNone;
string[] resources = new string[] { path }; // Just checking on one resource.
res = RmRegisterResources(handle, (uint)resources.Length, resources, 0, null, 0, null);
if (res != 0)
throw new Exception("Could not register resource.");
//Note: there's a race condition here -- the first call to RmGetList() returns
// the total number of process. However, when we call RmGetList() again to get
// the actual processes this number may have increased.
res = RmGetList(handle, out pnProcInfoNeeded, ref pnProcInfo, null, ref lpdwRebootReasons);
if (res == ERROR_MORE_DATA)
{
// Create an array to store the process results
RM_PROCESS_INFO[] processInfo = new RM_PROCESS_INFO[pnProcInfoNeeded];
pnProcInfo = pnProcInfoNeeded;
// Get the list
res = RmGetList(handle, out pnProcInfoNeeded, ref pnProcInfo, processInfo, ref lpdwRebootReasons);
//pnProcInfo contains all the processes that are using the pkg
if (res == 0)
{
// Enumerate all of the results and check for waf3 process and not same session
for (int i = 0; i < pnProcInfo; i++)
{
try
{
if (includeCurrentUserProcesses)
{
if (processInfo[i].strAppName == currentProcess.ProcessName)
return true;
}
else
{
if (processInfo[i].strAppName == currentProcess.MainModule.ModuleName && processInfo[i].TSSessionId != currentProcess.SessionId)
return true;
}
}
// catch the error -- in case the process is no longer running
catch (ArgumentException)
{ }
}
}
else
throw new Exception("Could not list processes locking resource.");
}
else if (res != 0)
throw new Exception("Could not list processes locking resource. Failed to get size of result.");
}
finally
{
RmEndSession(handle);
}
return false;
}
#endregion