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I managed to resolve the Issues without parameterized queries mate. Because I am creating the dataset at runtime and then populating it to a database at runtime and dynamically assigning them to columns I had to go the route I went. For some reason it is working perfect now. I understand that parameterized queries workes better and they are safer but I am tunning against an MS Access DB which is not that friendly with stored procedures as far as I have read.
Excellence is doing ordinary things extraordinarily well.
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Kwagga wrote: Access DB which is not that friendly with stored procedures
No one said anything about stored procedures.
Aren't you using parameters within Crystal?
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Hi,
I have worked through the MSDN example of Creating an N-Tier Data Application. However, I'm struggling to get started with my 'save changes' functionality for a DataGridView . Can anyone offer any advice?
My solution consists of SQL Server 2008 (I'm using the NorthWind sample database to go along with the walkthrough linked above), a Data Access Tier, Data Entity Tier, DataService and Presentation Layer and currently my app displays the DataSet in two DataGridView s.
I understand the order of method invocations that is required to achieve what I want, but I'm struggling to get started with the coding of it. I.e capturing the changes made in the DataGridView , saving them to the DataSet and then committing the DataSet to the database via the DataService and Data Access Tier.
Apologies for the long post and if I have missed out any info that would help you answer my question.
Anthony
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FYI: your hyperlink is incorrect, it refers to your own message.
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Ah so it did, as I've corrected it.
Thanks for pointing that out.
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Hey buddies !
I want to develop a WinForm Application (C#) in which i can navigate to next or previous Photos (in pictureBox control)..
Example :
> I have dragged a picturebox control on form.
> then dragged two button for next and previous.
> and i want that when i click on next button then another picture should be come (just like in windows picture and fax viewer)
> all picture should be in Resource file.
Hope so u guy are able to understant that what i want.i m a newbie, and i tried but not succeded...when i click first time on button next picture comes out but on second click nothing happens.
i m doing this..
on button click event code is as follow
picturebox1.Image = Properties.Resource.PIC1;//this event takes me to next image but not more forward.
help me out
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You will either have to keep a record of where you are ("showing picture one", "showing picture two" ...) or check which picture you are displaying and move to the next.
if (picturebox1.Image == Properties.Resource.Pic1)
{
... Move to picture two
}
You could use if..else or switch , it depends on how many you have, and how you are with switch statements!
Me, I would set up an array of Images, loaded at form load from the resources, and have an integer index into it which I increment and check each time.
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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How to check the values of the checkbox true/false control in Datagridview and then post it values to the database?
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Please read the instructions at the top of the page "How to get an answer to your question" before you post. "Hello Sir i am muthu from kumbakonam" is not a helpful subject for a question - instead describe your problem in a few words: "Use Checkbox in DataGridView" tells potential answerers a lot more, and doesn't waste thier time if they cannot help you.
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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Hi there,
when we want to use a function from a C dll, we have to declare it like:
[DllImport(ThirdPartyDll)]
private static extern int SomeFunction(string Param1, and so on);
Now, ThirdParty provides a row of dlls with all of them implementing that SomeFunction with the same signature (only some interenal parameters differ leading to different results). We want our users to select the dll they want to use for that purpose. That means, ThirdPartyDll in [DllImport(ThirdPartyDll)] must become a variable instead of a constant. But C# does not allow a variable at the DllImport declaration.
In old C++, that's possible, I do not remember the exact way, there was some use of function pointers.
But this is a program written in C# (.Net 2.0). How can we do that here?
Looking forward to your hints.
Bernhard
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I don't know if you have better ways to do this, but one idea is to declare them all and after that you define a Delegate with the same signature.
This way you can assign the corresponding function to the delegate, this way you got pretty much the same functionality that you get with pointers to functions.
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Thanks for this idea. In most cases it would do the job. But ThirdParty might provide another such dll with a new name, and it cannot be used before the function of that specific dll was declared. In C++ there is some way to do that, but in C#?
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Bernhard,
Dynamically loading an unmanaged dll uses an almost direct translation of C code.
In the example note the use of
1) the UnmanagedFunctionPointer attribute on the SomeFunction delegate declaration
2) the Marshal.GetDelegateForFunctionPointer method to convert the raw function pointer to the C# friendly delegate.
using System;
using System.Runtime.InteropServices;
internal class DynamicLoad {
[DllImport("kernel32.dll", SetLastError = true)]
private static extern IntPtr LoadLibrary(String dllToLoad);
[DllImport("kernel32", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
private static extern IntPtr GetProcAddress(IntPtr hModule, string procName);
[DllImport("kernel32.dll", SetLastError = true)]
private static extern bool FreeLibrary(IntPtr hModule);
[UnmanagedFunctionPointer(CallingConvention.StdCall, SetLastError = false, CharSet = CharSet.Ansi)]
internal delegate int SomeFunction(string Param1);
private IntPtr dllPtr;
internal SomeFunction someFunction;
internal Boolean Load(String dllPath) {
dllPtr = LoadLibrary(dllPath);
if (dllPtr != IntPtr.Zero) {
try {
someFunction = (SomeFunction)Marshal.GetDelegateForFunctionPointer(
GetProcAddress(dllPtr, "SomeFunction"),
typeof(SomeFunction));
} catch (ArgumentNullException) {
Unload();
}
}
return (dllPtr != IntPtr.Zero);
}
internal void Unload() {
bool result = FreeLibrary(dllPtr);
dllPtr = IntPtr.Zero;
}
}
Alan.
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Alan,
wow! Extremely complicated don't-c-sharp-code, but it works!
Lots of thanks,
Bernhard
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Not really so complicated - he just makes it look complicated with his loony formatting . However, I gave him a lolly because it's a very good answer.
Phil
The opinions expressed in this post are not necessarily those of the author, especially if you find them impolite, inaccurate or inflammatory.
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Ok, now, that's an answer . And now here's a question, what if SomeMethod's signatures does not match the delegate signature?? Do I get an ArgumentException?? I know this should be a problem since he knows the signature of the method. Just asking out of curiosity.
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Just tested that. I inserted another parameter before the normal first parameter (which is the name of a file), then called the function. The int value returned by the function is an error code, now the result was 1. According to the documentation of the manufacturer "1" means "File access error", i.e. my first parameter (although it was an int) was treated as the expected parameter (a string denoting the file name), and extra parameters seem to have been discarded.
In summary, you do not get an exception, the function just executes (and may happen to return an error code or destroy your system).
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Thank you
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Hi,
I made a web browser in .net c# windows application. In that how can i change appearance of the win form...like changing skin of the browser. How can i archive this using c#.
Thank you.
krishna
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Man, you're writing in your question, that this is WinForms question, so why don't you ask it on WinForms forum?
Don't forget to rate answer, that helped you. It will allow other people find their answers faster.
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lukasz_nowakowski wrote: Man, you're writing in your question, that this is WinForms question, so why don't you ask it on WinForms forum?
He wrote it in C#, why should he ask it in the Windows Forms forum then and not here in C#?
"I love deadlines. I like the whooshing sound they make as they fly by." (DNA)
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Because he doesn't ask about feature of the C#, only about a feature of the Windows Forms. If he knew how to do it in Visual Basic, but had a problem translating it to C#, it would be a good place to ask, but he asks (not sure how to do it, so I'm guessing here) for a method or property, that manages apearance of Windows Forms control.
Following your thinking, CodeProject forum should be truncated to C#, Visual Basic, C++, PHP, ... (hope you see the pattern here). And when someone has a problem with Windows Forms or ASP.NET, he has to search in all languages instead of just searching forum more specific to his needs.
That's why I think, this question should go to Windows Forms, not C#.
Don't forget to rate answer, that helped you. It will allow other people find their answers faster.
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i want that my prefix or my first 4 char value in my textbox which is "SPR-" cannot be deleted or modify by the user...how to code that.. plz.
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One would assume that you are going to do “something” with the contents of the TextBox after the user has finished entering data into it; in which case, if the data does not have an “SPR-“ prefix, add it after the fact.
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Use a MaskedTextBox[^] instead, and set the mask to "SPR-&&&&&&&&&&&" where the number of '&' characters equals the max length of the input.
You can remove the underscore by setting the PromptChar property to space.
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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