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Hmmm.. what I wrote in my original message aren't that my (assumed) needs?
I want to implement offline pessimistic locking on database records (by offline I mean without keeping a connection and transaction alive from reading to updating). And (I think) for that I need the outlined lock manager.
If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson
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The first rule of lock management is: DON'T use it (locks) (unless you have to).
The second rule of lock management is: DON'T use pessimistic locking (unless you have to); use optimistic locking.
I have yet to see where you "need" both, even though you "want" both.
A "transaction" is effectively a "lock"; which does not involve you worrying about locks.
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Gerry Schmitz wrote: I have yet to see where you "need" both, even though you "want" both.
I didn't write I'd want both.
Gerry Schmitz wrote: A "transaction" is effectively a "lock"; which does not involve you worrying about locks.
I wrote that I don't want to keep a connection and transaction alive from reading to updating.
If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson
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"Use the virtually unlimited space available in a message to provide a detailed question that allows people to understand what kind of help is needed."(Lefevre 14-Mar-2016)
Transactions can be asynchronous.
I'm done here.
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Gerry, I absolutely didn't mean to test your patience and I apologize if I have. I'm oblivious to asynchronous transactions which maybe partly explains the "phaseshift" between our messages. I'll look into that, thank you for the pointer.
If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson
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I am new to c# and using windows forms.
I have a DataGridView control on a form and I need to allow a user to multi-select rows (when they click on a row) without using the CTRL key (no keyboard is available - they are using a touch screen) and without using check box column. I have enabled the mutli-select property.
Please help me how to do that, Thank you
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Why can't you use a checkbox if it is easier?
Since it's a "touch screen", I assume the "public" will be using it.
The "public" is generally familiar with widgets such as "checkboxes", "radio buttons", "movers", "selected color", etc. and how they work when it comes to "selecting" or "showing" selections.
You're not doing anyone any favors if you think you have found a "new" way to show selected items.
Anyway, even if you use a checkbox, you can still "hide" it.
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I would like to try out for a small side project where:
I load up 7 (and maybe 10) images one on top of the other. With a slider I would like to make the first image more and more transparent (showing the second image) and sliding more and more, each of the "layers" is shown. it has to be "fluent" though, so not a "show/noshow", but rather a percentage transparent.
If that should ever work, I would like to try to do the same, but with multiple "timelapse". In effect, playing 7 (or 10) "videos" at the same time and sliding down/up, but if the first thing would work, I'll already be quite happy.
Does anyone know a good tutorial or article for this? google was not really helpful (except that stacking pictureboxes in winforms isn't going to work), most entries are about png transparency. WPF is not a problem.
If I get it to work, I promise an article 
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One way to find out is to look at GIMP - it's open source, as you know - it has Layers, whose Opacity can be individually adjusted via a slider.
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Is it not simply tying the transparency (alpha I think) Opacity, thank OG, to the position of the slider when the transparency reaches 100 set the z property of the image and then work with the next image in the stack.
Sounds simple but I'll bet there are a bunch of pitfalls in there.
Never underestimate the power of human stupidity
RAH
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I did an article a while back that performs different image transitions[^]. Take a look at the "fade" transition - it should give you some clues on how to proceed.
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If you're going to use WPF (and you should), then for your project you need to get familiar with the "Storyboard" class: that's how you animate properties like the ones you will be interested in: Opacity, (Window / Control) Left, Right, Top...
I've animated transparent panels that darken when they slide in to cover a "virtual keyboard" on a kiosk when a cc is being read (or something).
Sounds like the same thing you want to do (except more panels).
(I've confirmed the MediaElement can play actual videos (e.g. mp4) "transparently"!)
Keep in mind that transparency requires more graphics power.
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I want to check the entered date and time lies in between two date and time.
eg:
if i entered a data at "16-03-2016 4:00pm"
and entered another data at "17-03-2016 2:pm"
for both datas entered the date should be saved as 17-03-2016.
whenever anyone enters data in between those two date and time the date should be saved as 17-03-2016. Date is saved on time basis. can any one help me plz..
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Check the time (hour) component of the datetime value
If it is greater than 16 add 8 hours
DateTime dt = DateTime.Now.AddHours(8);
store as a date only value.
This will depend on the database you user, MSSQL has a date data type which removes the time component.
Never underestimate the power of human stupidity
RAH
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sorry sir..i did nt understand much..i use mssql... front end C#.net..want to check date and time using C#.net..nd no need of saving time...on time basis dates are saved..
plz help me..
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For a start learn to write a sentence. Do NOT use txt speak otherwise you will be ignored.
Do you know what the DateTime [^]data type is. Take a look at the examples on that page.
Never underestimate the power of human stupidity
RAH
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{
DateTime dt = dateTimePicker1.Value.Date.Add(dateTimePicker1.Value.TimeOfDay);
string m = dateTimePicker1.Value.ToString("hh:mm tt", CultureInfo.InvariantCulture);
DateTime dtcheck = Convert.ToDateTime(m);
string n = "2:00 PM";
string s ="4:00 PM";
TimeSpan end = new TimeSpan(2,0,0);
TimeSpan dtstrt = new TimeSpan (4,0,0);
string dat = dateTimePicker1.Value.ToString("dd-MM-yyyy",CultureInfo.InstalledUICulture);
if (dateTimePicker1.Value.Date == DateTime.Today)
{
bool silenceAlarm = TimeBetween(DateTime.Now, end, dtstrt);
}
}
bool TimeBetween(DateTime datetime, TimeSpan start, TimeSpan end)
{
TimeSpan now = datetime.TimeOfDay;
if (now >= start)
return true;
else if (now >= end)
return false;
else return true;
}
i use above code...
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DateTime dt = dateTimePicker1.Value.Date.Add(dateTimePicker1.Value.TimeOfDay);
string m = dateTimePicker1.Value.ToString("hh:mm tt", CultureInfo.InvariantCulture);
DateTime dtcheck = Convert.ToDateTime(m);
Why on earth would you convert a DateTime to a String, just so you can convert it back to a DateTime? If the values are not already in DateTime form, then convert them into it as soon as possible. You can then do a simple comparison to ensure the later is actually later than the earlier one. Mycroft has already given you the link to the documentation, please study it.
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The DateTime structure always includes a "date" and "time" component.
You can however effectively ignore the time by using the ".Date" property: e.g.
Console.WriteLine( DateTime.Now.Date );
... displays: 3/16/2016 12:00:00 AM
And this works:
if ( dt1.Date == d2.Date) {}
etc.
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{
DateTime resultdate = new DateTime();
DateTime dt = dateTimePicker1.Value.Date.Add(dateTimePicker1.Value.TimeOfDay);
string dts = DateTime.Now.Date.ToString("MM/dd/yyyy");
string dte = DateTime.Now.Date.ToString("MM/dd/yyyy");
string st = dts+" 04:00:00 PM" .ToString();
string end = dte+" 02:00:00 PM".ToString();
DateTime start = Convert.ToDateTime(st);
DateTime stop = Convert.ToDateTime(end);
if (dt >= start || dt <= stop)
{
if (dt >= start)
{
resultdate = dateTimePicker1.Value.Date.Add(dateTimePicker1.Value.TimeOfDay).AddDays(1);
}
else
resultdate = dt;
}
this is the answer...
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There are other possibilities.
Also, if you are going to use a "value" in more than one place, and it has to be the same, then you need to re-think how you handle "Now"...
It is possible for dts and dte to have different "Now" .Date values due to interrupts (e.g. around midnight); do this instead:
DateTime now = DateTime.Now.Date;
DateTime start = now.AddHours( 16 );
DateTime stop = now.AddHours( 14 );
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I have a simple console application that allows users to keep adding an employee to an array until they answer no to a prompt asking them if they want to add more employees.
Below is my code but it is only showing the first employee and not the subsequent employees that were added.
class Program
{
static void Main(string[] args)
{
Employee[] employees = new Employee[5];
int employeeCount = 0;
bool addMoreEmployees = true;
String answer = string.Empty;
while(addMoreEmployees)
{
Employee emp = new Employee();
emp.AddEmployee();
if (employees[employeeCount] == null)
{
employees[employeeCount] = emp;
}
employeeCount++;
Console.WriteLine("Do you want to add more employees?");
answer = Console.ReadLine().ToUpper();
if (answer == "NO" || employeeCount > 5)
{
addMoreEmployees = false;
}
}
foreach (Employee employee in employees)
{
Console.WriteLine("firstname: {0} \n" +
"lastname: {1} \n" +
"department: {2} \n" +
"salary: {3}",
employee.FirstName,
employee.LastName,
employee.Department,
employee.Salary
);
Console.ReadLine();
}
}
}
public class Employee
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string Department { get; set; }
public double Salary { get; set; }
public void AddEmployee()
{
Console.WriteLine("Enter employee's firstname.");
this.FirstName = Console.ReadLine();
Console.WriteLine("Enter employee's lastname.");
this.LastName = Console.ReadLine();
Console.WriteLine("Enter employee's department.");
this.Department = Console.ReadLine();
Console.WriteLine("Enter employee's salary.");
this.Salary = Convert.ToDouble(Console.ReadLine());
}
}
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In your code, Console.ReadLine() is called withing the loop. So you will only see next employee when you hit enter key. Just take out that line of code from the loop and you will be fine.
Also place a null check in the foreach loop or else it will throw NullReference exception.
"You'd have to be a floating database guru clad in a white toga and ghandi level of sereneness to fix this goddamn clusterfuck.", BruceN[ ^]
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Thanks for your reply that did the trick.
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