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You haven't supplied any relevant code so it's impossible to tell you with any accuracy.
But, the try/catch block should surround only the processing of a single record, NOT THE ENTIRE LIST OF THEM.
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That sums it up.
It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food
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There is no specific way to answer you because we have no idea how you are processing the records.
One way to do it is to process one record at a time and put that code in a try catch, inside the loop. That way the loop will continue. However, if the problem is that the database is not available, for example, then it's going to throw an exception for every single record you are processing.
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Ask what you want the try-catch to do; retry the current item, or skip it and progress to the next.
Retrying should be limited.
Bastard Programmer from Hell 
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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To add to what the others have said, you might also want to look at why the record failed - what did it contain that you didn't expect? Was it something you should have expected, or been able to handle?
For example, if a user is to enter a page full of information and a single item is wrong, you shouldn't invalidate the whole page - just get the user to enter the right value.
We can't see your screen, access your HDD, or read your mind - so we have no idea what your code is doing, or how it is doing it; but graceful error handling is an important part of any app!
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
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I'm trying to get the list of allocated ranges for a sparse file on Windows 10 from a C# program. DeviceIOControl requires an array of FILE_ALLOCATED_RANGE_BUFFER structures as the output buffer. I just can't seem to get the correct way of passing these. So far I have....
public static bool GetSparseRange(SafeFileHandle hdrive, in FILE_ALLOCATED_RANGE_BUFFER query, ref FILE_ALLOCATED_RANGE_BUFFER[] response, int count)
{
int nInBufferSize = (int)Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER));
IntPtr lpInBuffer = Marshal.AllocHGlobal(nInBufferSize);
Marshal.StructureToPtr(query, lpInBuffer, true);
uint bytesread=0;
IntPtr[] ptrArr = new IntPtr[count];
for (int i = 0; i < count; ++i)
{
ptrArr[i] = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER)));
Marshal.StructureToPtr(response[i], ptrArr[i], true);
}
bool rc = DeviceIoControl(
hdrive, // device to be queried
(uint)EIOControlCode.FsctlQueryAllocatedRanges, // operation to perform
lpInBuffer, (uint)nInBufferSize, // input buffer
ptrArr, (uint)(nInBufferSize * count)), // output buffer
ref bytesread, // # bytes returned
IntPtr.Zero); // synchronous I/O
// Get the last error and display it.
int error = Marshal.GetLastWin32Error();
for (int j = 0; j < count / nInBufferSize; ++j)
{
if (j < bytesread / nInBufferSize)
Marshal.PtrToStructure(ptrArr[j], response[j]);
Marshal.FreeHGlobal(ptrArr[j]);
}
Marshal.FreeHGlobal(lpInBuffer);
return rc;
}
However this return rc=false, byteread=0 and error=5.
Can anyone suggest the correct way to do this?
Thanks
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He was so casual about "error 5" that I assumed everyone knew what it meant, except me ...and it was somehow not relevant.
It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food
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Yeah, At least one of his problems is ERROR_ACCESS_DENIED but it's entirely possible that there are other errors. I don't see anything else that stands out. I guess it would be nice to know how the SafeFileHandle hdrive is obtained.
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Radnor,
You were on the right track. The program was running as administrator so the "Access denied" was confusing me as well. The SafeFileHandle was created like this ...
using (dd = new FileStream(path + ".dd", FileMode.Open, FileAccess.Write, FileShare.Write))
{
bool finished = NativeMethods.GetSparseRange(ldd.SafeFileHandle, query, ref response, 1024);
}
So when the DeviceIoControl was called the file was empty which for some reason caused the return code 5.
Changing the FileStream creation for an existing file stopped the error.
However now I get an 0x00000057 error, parameter error which brings me back to the original question as how to pass an array of structures to DeviceIoControl.
This is what I've tried, the output buffer is the issue I think....
public static bool GetSparseRange(SafeFileHandle hdrive, in FILE_ALLOCATED_RANGE_BUFFER query, ref FILE_ALLOCATED_RANGE_BUFFER[] response, int count)
{
int nInBufferSize = (int)Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER));
IntPtr lpInBuffer = Marshal.AllocHGlobal(nInBufferSize);
Marshal.StructureToPtr(query, lpInBuffer, true);
uint bytesread=0;
int nOutBufferSize = nInBufferSize * count;
IntPtr lpOutBuffer = Marshal.AllocHGlobal(nOutBufferSize);
bool rc = DeviceIoControl(
hdrive,
(uint)EIOControlCode.FsctlQueryAllocatedRanges,
lpInBuffer, (uint)nInBufferSize,
lpOutBuffer, (uint)nOutBufferSize,
ref bytesread,
IntPtr.Zero);
int error = Marshal.GetLastWin32Error();
Marshal.PtrToStructure(lpOutBuffer, response);
Marshal.FreeHGlobal(lpInBuffer);
Marshal.FreeHGlobal(lpOutBuffer);
return rc;
}
Thanks
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Hello,
Your GetSparseRange function is working for me. I simply wrote a quick test application and used the function you provided.
using System;
using Microsoft.Win32.SafeHandles;
using System.Runtime.InteropServices;
using System.Text;
using System.IO;
using System.Diagnostics;
namespace SparseRanges
{
#region Structs
struct FILE_ZERO_DATA_INFORMATION
{
public long offset;
public long zero;
}
struct FILE_ALLOCATED_RANGE_BUFFER
{
public long offset;
public long length;
}
#endregion
class Program
{
#region Const ints
const uint FSCTL_SET_SPARSE = 590020;
const uint FSCTL_QUERY_ALLOCATED_RANGES = 606415;
#endregion
[DllImport("kernel32.dll", SetLastError = true)]
extern static bool GetVolumeInformation(string vol, StringBuilder name, int nameSize, out uint serialNum, out uint maxNameLen, out uint flags, StringBuilder fileSysName, int fileSysNameSize);
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool DeviceIoControl([In] SafeFileHandle hDevice, [In] uint dwIoControlCode, IntPtr lpInBuffer, [In] int nInBufferSize, IntPtr lpOutBuffer, [In] int nOutBufferSize, ref uint lpBytesReturned, [In] IntPtr lpOverlapped);
public static bool GetSparseRange(SafeFileHandle hdrive, in FILE_ALLOCATED_RANGE_BUFFER query, ref FILE_ALLOCATED_RANGE_BUFFER[] response, int count)
{
int nInBufferSize = (int)Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER));
IntPtr lpInBuffer = Marshal.AllocHGlobal(nInBufferSize);
Marshal.StructureToPtr(query, lpInBuffer, true);
int nOutBufferSize = nInBufferSize * count;
IntPtr lpOutBuffer = Marshal.AllocHGlobal(nOutBufferSize);
uint bytesread = 0;
bool rc = DeviceIoControl(hdrive, FSCTL_QUERY_ALLOCATED_RANGES, lpInBuffer, nInBufferSize, lpOutBuffer, nOutBufferSize, ref bytesread, IntPtr.Zero);
int error = Marshal.GetLastWin32Error();
Marshal.FreeHGlobal(lpInBuffer);
Marshal.FreeHGlobal(lpOutBuffer);
return rc;
}
private static void PrintSparseRange(FILE_ALLOCATED_RANGE_BUFFER range)
{
Console.WriteLine("{0:d} offset, length = {1:d}", range.offset, range.length);
}
static void Main(string[] args)
{
uint temp1, temp2, flags, bytes=0;
if (GetVolumeInformation("C:\\", null, 0, out temp1, out temp2, out flags, null, 0))
{
uint supports_sparse = flags & 0x40;
if (supports_sparse == 0x40)
{
Console.WriteLine("Volume supports sparse files...");
string sparse_filename = Path.GetTempFileName();
System.IO.FileStream f = System.IO.File.Create(sparse_filename);
if (DeviceIoControl(f.SafeFileHandle, FSCTL_SET_SPARSE, IntPtr.Zero, 0, IntPtr.Zero, 0, ref bytes, IntPtr.Zero))
{
Console.WriteLine("Successfully generated a sparse file.");
f.SetLength(10240);
FILE_ALLOCATED_RANGE_BUFFER[] response = new FILE_ALLOCATED_RANGE_BUFFER[64];
FILE_ALLOCATED_RANGE_BUFFER query;
query.length = 10240;
query.offset = 0;
int count = 64;
if(GetSparseRange(f.SafeFileHandle, query, ref response, count))
{
Action<FILE_ALLOCATED_RANGE_BUFFER> print_all = new Action<FILE_ALLOCATED_RANGE_BUFFER>(PrintSparseRange);
Array.ForEach(response, print_all);
}
f.Close();
Console.WriteLine("Removing temp sparse file.");
File.Delete(sparse_filename);
}
}
}
}
}
}
BobZscharnagk wrote: The SafeFileHandle was created like this ...
using (dd = new FileStream(path + ".dd", FileMode.Open, FileAccess.Write, FileShare.Write))
Any particular reason why you are opening the file without Read access?
Best Wishes,
-David Delaune
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Radnor,
Thanks for the reply and the time. When I tried your code, unmodified, i just get 64 lines of "0 offset, length = 0", which is because I think you didn't copy the Marshall'd response back into the passed response. I added two lines to your code...
f.SetLength(10240);
f.Write(new byte[] { (byte)'H', (byte)'e', (byte)'l', (byte)'l', (byte)'o' }, 0, 5);
and
int error = Marshal.GetLastWin32Error();
Marshal.PtrToStructure(lpOutBuffer, response);
Adding f.Write by itself should cause one of the blocks to be allocated and not show in the output. Testing with just this line gives the same result as if the write wasn't there.
Adding the second change, Marshal.PtrToStructure, causes an error "Quote: System.ArgumentException: 'The specified structure must be blittable or have layout information.
Which I think is where I started.
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Finally got it working....
public static int GetSparseRange(SafeFileHandle hdrive, in FILE_ALLOCATED_RANGE_BUFFER query, ref FILE_ALLOCATED_RANGE_BUFFER[] response, out int count)
{
int nInBufferSize = Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER));
IntPtr lpInBuffer = Marshal.AllocHGlobal(nInBufferSize);
Marshal.StructureToPtr(query, lpInBuffer, false);
uint bytesreturned = 0, command = (uint)EIOControlCode.FsctlQueryAllocatedRanges;
int nOutBufferSize = nInBufferSize * 1024;
IntPtr lpOutBuffer = Marshal.AllocHGlobal(nOutBufferSize);
DeviceIoControl(
hdrive,
(uint)command,
lpInBuffer, (uint)nInBufferSize,
lpOutBuffer, (uint)nOutBufferSize,
out bytesreturned,
IntPtr.Zero);
int rc = Marshal.GetLastWin32Error();
count = (int)bytesreturned / nInBufferSize;
for (int j = 0; j < count; ++j)
{
response[j] = (FILE_ALLOCATED_RANGE_BUFFER)Marshal.PtrToStructure(lpOutBuffer + (j * nInBufferSize), typeof(FILE_ALLOCATED_RANGE_BUFFER));
}
Marshal.FreeHGlobal(lpInBuffer);
Marshal.FreeHGlobal(lpOutBuffer);
return rc;
}
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Yep.
In my code sample I gave you you can add:
for (int i = 0; i < count; i++)
{
IntPtr ptr= new IntPtr(lpOutBuffer.ToInt64() + i * Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER)));
response[i] = Marshal.PtrToStructure<FILE_ALLOCATED_RANGE_BUFFER>(ptr);
}
Under the call to DeviceIoControl to marshal the unmanaged array.
I am a Windows API guy... I got involved to help you figure out why DeviceIoControl was giving you an ERROR_ACCESS_DENIED. Didn't know I would need to fix your C# code too. 
Glad you got it working, good luck. 
Best Wishes,
-David Delaune
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Hi, folks.
I created a user control with some properties and methods and used it in a Forms project where it appears many times. It's working fine.
But now I decided to improve some characteristics and I eliminated some properties and added some.
The problem is that the forms where this control appears show errors and it' very difficult to open the form. After I open the form I removed the old control and tried to add the new version, but it appears that only the old version is accepted.
What is the best way to substitute a control under these circumstances?
I use C# in Visual Studio 2019.
Thanks.
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The problem is probably that as you say:
Quote: I eliminated some properties and added some.
If any of the classes that use your control are referencing those properties, the new version will just not work: the properties no longer exist.
The proper way to do that is to depreciate the properties, not remove them: that way they can still be used but there is a warning that they shouldn't be used in new projects.
That is documentation only, however - for later versions, you can make them actually obsolete: ObsoleteAttribute Class (System) | Microsoft Docs[^] but you should allow a good time for people to migrate to the newer version before that happens.
Often, a more developer friendly way to do this with drastic changes is to end support for the existing version, and develop a new version for future projects.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
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Make the properties obsolete? I'll read more about.
Thanks.
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You're welcome!
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
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Member 14792393 wrote: I decided to improve some characteristics and I eliminated some properties and added some.
A key question is what you did to the Forms that had instances of the UserControl that used the removed Properties: of course any attempted use/access of/to removed "anything" results in compile errors.Member 14792393 wrote: After I open the form I removed the old control and tried to add the new version, but it appears that only the old version is accepted
This just doesn't make sense: did you edit the form code to remove any code that used the UserControl instance, and, then, re-build the Project/Solution? Did you re-build the solution after adding the new version of the UserControl?
There is (imho) a defect in Visual Studio that has never been fixed: you can modify a UserControl ... for example, add some new Control to it ... and, the change doesn't appear in currently open design-time Form Windows even after you re-build the solution. However, if you close the designer window, and re-open it: the view has been updated.
«One day it will have to be officially admitted that what we have christened reality is an even greater illusion than the world of dreams.» Salvador Dali
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"did you edit the form code to remove any code that used the UserControl instance, and, then, re-build the Project/Solution? Did you re-build the solution after adding the new version of the UserControl?"
Yes, but the application is too big and has many instances of the control.
What I intend to do now is to rename the new version of the control and add it to the project. Then I open each form, erase the old version and insert the new version. After that I can remove the old version. It's a hard job, but I think it's the only way.
What do you think?
Thanks.
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If you really have removed Properties you have to realize that those Properties perhaps are used by the Designer-Script of your Form.
So you must open the DesignerScript of your Form, find those part which assignes the Properties of this Control and delete those Assignments which are not more existent ...
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good point from a slightly different angle 
«One day it will have to be officially admitted that what we have christened reality is an even greater illusion than the world of dreams.» Salvador Dali
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Maybe you're right. I'll take a look.
Thanks.
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you will see it ... 
And you are welcome ...
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Here is some sample data i have been provided using json post
{
"PropertyInfos": [
{
"Identification": {
"IDValue": "102"
},
"PropertyName": "Casa Bella",
"ManagementCompany": {
"ManagementCompanyName": "ACME Trusts",
"Identification": {
"IDValue": "2"
}
},
"Address": {
"Address": "425 Slopestyle Skies Se",
"City": "Lincoln",
"State": "NE",
"PostalCode": "67123",
"Email": "test@example.com"
}
},
{
"Identification": {
"IDValue": "20"
},
"PropertyName": "Tall Tower",
"ManagementCompany": {
"ManagementCompanyName": "ACME Trusts",
"Identification": {
"IDValue": "2"
}
},
"Address": {
"Address": "789 Steele Street",
"City": "Denver",
"State": "CO",
"PostalCode": "80206",
"Email": "tall.tower@example.com"
}
},
{
"Identification": {
"IDValue": "92"
},
"PropertyName": "Z Emerson",
"ManagementCompany": {
"ManagementCompanyName": "ACME Trusts",
"Identification": {
"IDValue": "2"
}
},
"Address": {
"Address": "2199 112th St S",
"City": "Chicago",
"State": "IL",
"PostalCode": "60444",
"Email": "test@example.com"
}
}
]
}
How can I convert this into a list or dictionary so i can then work with each of the entries and import them into my system using c#. if they were in a list or dictionary i would be able to go through the list and do what i need with each data entry. I am very new when it comes to working with JSON api and what not. Any help or pointers in the right direction would be awesome. Thank you guys!
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