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Hi all, I'm pretty new to C# and would like to have some questions answered regarding getting data from the user. Suppose I have a class called MyClass like the following:
Class MyClass
{
string firstName;
string lastName;
MyClass(string fName, string lName)
{
this.firstName=fName;
this.lastName=lname;
}
public string fN{ get { return firstName; }set { firstName= value; } }
public string lN { get { return _firstName; } set { lastName= value; }}
}
Then in the code behind of my aspx page I want to create an array of type MyClass and get firstName and lastName from the user and put them in the array.
I plan to have the user enter firstName and lastName into textboxes and insert them into the array by sending them in as parameters during the instantiation of the array. The following is what I have done but it does not work.
MyClass[] projects = new MyClass[4];
projects[0] = new Project(firstName, lastName);
Any help is greatly appreciated, thanks in advance
modified 9-Feb-14 3:08am.
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No, it won't work.
Or rather, it will - but not for long.
The problem is that you aren't thinking website - you are thinking desktop.
Websites do not work in the same way: the application is not running all the time, waiting for the user to do something. Instead, the website application is started again each time the user does something like request a page, press a button, and so forth. Which means that unlike a desktop application any data you assemble in your application ceases to exist as soon as the last bytes of data have going back to the client. If you don't store it somewhere permanent (or semi-permanent) explicitly, it is discarded, to make way for the next website / user combination.
If you want to keep a list of users, then you need to explicitly save the data, in a database, or in the Session, or in Cookies, depending on how permanent you need it to be.
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
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hi
Want to write a example of textbox other windows with SendMessage API
thank
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Don't post in multiple places: it duplicates work and that's annoying.
You posted this in QA, so leave it there.
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
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Hello Guys,
Am struck with a scenario here,
Am going to distribute my Front End tool developed using C# to 30 users computer.
They will be entering the values in it and that will be get stored in the SQL database in the Server location.
I want the computer name of users to be captured in the Sql database automatically with the user entering that value.
e.g:
User 1 will be entering the below details from Machine 1.
My Sql database will be getting the values entered by user 1 and additionally in one more column i want the "User 1" also to be captured.
(Can we use "LoggedOnUser" something like that retrive the userName to be entered on Clicking the submit button) ??
Same for Date also, Can we use "SysData" to be getting captured in Database
Please assist.
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The user is easy:
string username = (string) WindowsIdentity.GetCurrent().Name
Getting the date is even easier:
DateTime now = DateTime.Now;
Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952)
Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)
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and Environment.MachineName in your client code will get you the computer name.
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You now have the methods and keywords to use.
So your app needs to pass in the user name when it sends the data to the database. Every table in my databases has a Modified and ModifiedBy field and that information comes from the client application.
Never underestimate the power of human stupidity
RAH
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As an alternative to the above answers, if you want to do this from SQL, you can use the HOST_NAME[^] and SUSER_NAME[^] functions to get the computer name and username.
For the current date and time, you can use the SYSUTCDATETIME[^] function. (This will return a UTC value, which is the only sensible way to store times in a database.)
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
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hello guys i need ur help if i have data table
item value check
a 11
a 10
b 9
b 30
c 10
---------------------------------------
i need get the min value of item ech item as like that
item value check
a 11
a 10 x
b 9 x
b 30
c 10 x
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This looks like homework. Show what you have tried and explain your problems.
To get you started here is one possible way to get the minimum values.
Loop through the rows and store the minimum value for each unique "item" value. You can use a Dictionary<string, int=""> to store these unique items and the value. If the Dictionary contains the "item", test the value and store the minimum value; if it does not contain the "item", add it.
This is not the complete solution, so do not come back and say its does not work.
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Do some research into GROUP BY and the MIN operator
Select Item, min(value) from table
Group By Item
Never underestimate the power of human stupidity
RAH
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Hello All,
I'm looking for a way to connect to a Cisco Router via SSH and then interpret the output to perform different operations based on the output, i.e. username/password incorrect, enable mode, etc ...
I have already been able to achieve this using TELNET, but now I need to migrate to SSH.
Best Regards,
Sikas.
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I already searched, but didn't find anything useful!
Best Regards,
Sikas.
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There were lots of links in the search I did. And given that your question lacks any real detail it is impossible to offer anything more.
Veni, vidi, abiit domum
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I am writing a program which will connect to a I2C to USB controller. I am using WPF.
I decided to create a Device class to contain the hardware description and all its attributes so I can use them to display properties and have the end user modify the settings of the hardware.
I have most of the above working, except 2 attributes.
Most attributes are strings or int or byte, etc... so they are easy to work with, like the example below:
private string _name;
[Category("General")]
[ReadOnly(false)]
[DisplayName("Module Name")]
[Description("Enter descriptive string ")]
public string Name { get { return _name; } set { _name = value; OnPropertyChanged("Module Name"); } }
The 2 attributes I am having a hard time with need to have a list to populate.
So I read the hardware setting, and it returns that it supports I2C, SPI, and UART.
Now I want to be able to pass those to the "CommunicationType" attribute, and have it display as a list in the properties window.
To see if my program is working, I created the following class:
public class CommunicationType : IItemsSource
{
public ItemCollection GetValues()
{
ItemCollection sizes = new ItemCollection();
sizes.Add((int)PP_COM_Wrapper.enumInterfaces.I2C, "I2C");
sizes.Add((int)PP_COM_Wrapper.enumInterfaces.ISSP, "ISSP");
sizes.Add((int)PP_COM_Wrapper.enumInterfaces.JTAG, "JTAG");
sizes.Add((int)PP_COM_Wrapper.enumInterfaces.SPI, "SPI");
sizes.Add((int)PP_COM_Wrapper.enumInterfaces.SWD, "SWD");
sizes.Add((int)PP_COM_Wrapper.enumInterfaces.SWD_SWV, "SWD SWV");
return sizes;
}
}
Then in the attribute, I have the following:
private int _comtype;
[Category("Settings")]
[ReadOnly(false)]
[ItemsSource(typeof(CommunicationType))]
[DisplayName("Communication Type")]
public int CommunicationType { get { return _comtype; } set { _comtype = value; OnPropertyChanged("Communication Type"); } }
So when I run it, it gives the user the possibility to select from a drop down, one of the communication types.
Now the question is, how do I populate it programmatically. Some of the hardware only supports I2C and SPI, so I only want to populate the list with 2 items based on the hardware.
Any guidance or examples are greatly appreciated.
Thanks,
H-
modified 8-Feb-14 2:56am.
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Hi all,
Can any one help me how to use Abstract class and Interface class in developing web application using c# language.
Thanks
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Hi,
I have a strange problem when calling one of my C++ dll functions from within C# code. Even though I have a work around but it is not making sense to me what caused the problem in the first place and would like to understand why.
I am writing below a very simple code that produces the problem:
Basically, My dll function returns a pointer to a null terminate string (const char *) that I would like to import it as a string in c# code.
The c++ DLL function :
const char* ReturnSomeString()
{
static string result="The string";
return result.c_str();
}
The C# code:
[DllImport(@"thedll.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
[return:MarshalAs(UnmanagedType.LPStr)]
public extern static string ReturnSomeString();
public void function()
{
string result = ReturnSomeString();
}
When I run the c# code, sometimes it works, sometimes the result is garbage and most of the times it crashes with with exception message :
An unhandled exception of type 'System.AccessViolationException' occurred in theapplication.exe
Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
As I mentioned, I have some couple work arounds but still want to understand why the above methodology does not work.
Work around 1:
---------------------
change the C++ code to not to use string class and just use the standard ansi char[] keeping the C# code unchanged.
Work around 2:
-----------------------
Keep the C++ code as is (using string class) but modify C# code:
[DllImport(@"thedll.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
public extern static IntPtr ReturnSomeString();
public void function()
{
string result = Marshal.PtrToStringAnsi(ReturnSomeString());
}
Please help me explaining what is wrong with the first method.
Thanks for taking the time looking into this.
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It's possible that the string being returned is not properly null-terminated.
Or it's possible that the C++ function is returning a locally declared variable, in which case it goes out of scope at the end of the C++ function.
Post the code of the C++ function.
The difficult we do right away...
...the impossible takes slightly longer.
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Thanks Richard for your reply.
This is what I thought initially so I made sure that the local string will never go out of scope by declaring it as "static". According to C++ documentations the string::c_str() supposed to return a pointer to null terminated string:
http://www.cplusplus.com/reference/string/string/c_str/[^]
I agree with you, it sound like something happens to the buffer that it becomes no longer valid but I am not sure what happens exactly!.
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Member 4211040 wrote: I agree with you, it sound like something happens to the buffer that it becomes no longer valid but I am not sure what happens exactly!.
Whatever the problem is, I'm sure it is more likely to be on the C++ side than the C# side.
The difficult we do right away...
...the impossible takes slightly longer.
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