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nirmalgopalakrishnan wrote: I am unable to determine what is the problem here
From a previous post you have the following code:
byte[] bytesofphotosretrive;
bytesofphotosretrive = (byte[])r["photo"];
MemoryStream mst = new MemoryStream(bytesofphotosretrive);
{
frm1.pictureBox5.Image = Image.FromStream(mst);
}
So you need to find out why mst is null at this point. Your code is assuming that you always get a valid byte array from r (whatever that is), and hence a valid stream. However, if either of these commands do not return the expected result you are going to have a problem which you are not catering for. You should never assume that method calls like this will always succeed; add some error checks so you can diagnose it properly when it fails.
One of these days I'm going to think of a really clever signature.
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Thank you for your response. The link which you provided was really helpful. But i am not sure how to include the same in my application, since i am saving data from 15 text boxes.
I am confused as to where to include the image details.
Regards,
Nirmal
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I have a form that has an array of text boxes dynamically added to a splitcontainer on a form. I use the same array to add text boxes to the form twice (different data for different table). I would like to use an event handler, preferably once, to change background color to yellow when textbox[i] receives focus, and back to white when it loses focus. I am currently going around in circles. Can anyone help me? Thanks for your input
Everett
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Add in a lambda, at the point where you create the textboxes. Like the example below;
public Form1()
{
InitializeComponent();
var tb = new TextBox();
tb.GotFocus += delegate (object s, EventArgs a)
{
(s as TextBox).BackColor = Color.Red;
};
tb.LostFocus += delegate(object s, EventArgs a)
{
(s as TextBox).BackColor = Color.Green;
};
Controls.Add(tb);
}
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hi, your idea is right, but the textbox has't the event GotFocus & LostFocus, instead of, has the event Enter & Leave.
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Works beeeautiful. Thank you so much Eddy
Everett
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I am rewriting a desktop application in VS2010 that was written in .Net 1.1. While doing so, I decided to add a couple of features to the app. One is a data source for a drop down list. I am using a local database file (.sdf) for the data.
I noticed in the <namespace>.Properties.Settings file that the connection string is a hard link to where I entered the file location (which is C:\Users\<username>\Documents\db\<filename>). I need this to be more dynamic, due to the fact this app will be on many different computers.
I tried editing to :
"Data Source = " + System.Environment.GetFolderPath(System.Environment.SpecialFolder.MyDocuments) + @"\dbs\latefee.sdf")]
But I receive the following error at compile time:
Error 1 An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type C:\Users\brian\AppData\Local\Temporary Projects\latefeedisc\Properties\Settings.Designer.cs 29 68 latefeedisc
How do I correct this?
Thank you in advance.
Jude
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Didn't you read the warning at the top?
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated by a tool.
// Runtime Version:4.0.30319.544
//
// Changes to this file may cause incorrect behavior and will be lost if
// the code is regenerated.
//
//------------------------------------------------------------------------------
?? 
You aren't supposed to modify that file. You should set the property in the constructor of your window.
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TheJudeDude wrote: I need this to be more dynamic
More dynamic than a settings-file?
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I apologize for my ignorance.
Jude
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Don't. It wasn't "ignorant", just overlooked some semantics that "could" give a hint.
It's a real settings-file; now, if only the database-name (or path) is going to differ, it'd might be neat to use a connection-string with a literal set of characters in the place where the databasename should be, and to Replace the literal with the actual path just before using the string.
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Oh, get off the Replace kick! 
Possibly use an environment variable and let the system do the replace.
But I suspect that the poster doesn't actually want to use the settings file at all. I'd write my own config file. :shrug:
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So, you want the system to do a simple literal replace for you, but you want to roll your own config file implementation? Clever  . Are you also going to write all the cool stuff that you get for free with config files such as encryption, versioning, editing through a simple GUI in VS, backwards compatibility, etc?
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LOL. You mean so you can impose your crazy formatting on it?
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Neato. How do you integrate with the Visual Studio designer? You should totally write an article about that aspect of it.
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SledgeHammer01 wrote: How do you integrate with the Visual Studio designer?
Configuration files via the designer? Myself I absolutely despise that. Every time you touch it it re-writes the file. Which means that all formatting is lost. And all documentation.
So you have a file that is intended to be manually edited not using VS which has no formatting and no documentation. And which isn't even necessarily guaranteed the have the same ordering between point releases.
So an absolute mess.
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jschell wrote: Every time you touch it it re-writes the file
Yes, it does.
jschell wrote: Which means that all formatting is lost.
It does mess up the formatting, I'll agree with that. Since it's an XML file, I just hit the "Format Document" button and it fixes it. Not enough of an annoyance to give up the designer editor IMO.
jschell wrote: And all documentation.
You put documentation in your config file? Thats an extremely odd place for documentation seeing as the .config files are NOT meant to be edited manually by end users. They are meant to be edited by people who know what the settings are (i.e. developers, etc).
jschell wrote: guaranteed the have the same ordering between point releases
Last time I checked, XML and .config files were unordered formats. If you are relying on the order of tags in an XML and/or .config file... "ur doin' it wrong".
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SledgeHammer01 wrote: You put documentation in your config file? Thats an extremely odd place for
documentation seeing as the .config files are NOT meant to be edited manually by
end users. They are meant to be edited by people who know what the settings are
(i.e. developers, etc).
No idea what kind of "end users" you have but my end users are Operations and Support personnel. And they are specifically the people that need to edit the configuration values.
Also no idea how you release software but busienss needs often drive new feature releases along, of course with bug fixes. And those can all require configuration values. So changes happen frequently.
Also although it might be nice to have a formal operations manual actually producing that seems to be a problem at most places I work at. And configuration files that have more than just a couple entries require documentation. Which either means putting it in the configuration file or putting it in another file. If it is put in another file then Operations/Support must be told about it. Repeatedly.
And of course to create a actual operations manual means that I, and no one else, would need to produce the documentation in the first place. Far as I am concerned since I know Operations/Support will be looking to the file anyways the documentation that is in there is going to be the source for the formal document anyways.
SledgeHammer01 wrote: Last time I checked, XML and .config files were unordered formats.
Both of those are entirely incorrect.
XML can be unordered or ordered.
And MS config files have some sections that require specific ordering.
But that doesn't have anything to do with what I am talking about...
SledgeHammer01 wrote: If you are relying on the order of tags in an XML and/or .config file... "ur
doin' it wrong".
If if fact that had anything to do with delivering a configuration file then you would in fact be correct. But it doesn't.
The order however does matter when Operations/Support uses standard difference tools to compare configuration files. Such as what they might do when they need to install a new major version or point release and they want to insure production machines have the same values with a new configuration file and the old one.
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jschell wrote: No idea what kind of "end users" you have but my end users are Operations and
Support personnel. And they are specifically the people that need to edit the
configuration values.
Same kind. I've noticed they are often too retarded to manually edit config files, so I usually provide an easy to use GUI for them (or at the very least, send them a whole new config file they just replace the old one with). For applications that go out to end users, asking an end user to change a config file is asking for trouble. Your GUI should do all that.
I know where you're going next... web.configs, web services, etc. don't have GUIs. Well, for a production application, I usually have an admin app or admin portal that controls the system. Much better design.
Also, if you want a simple generic thing, you could do what I did. Have a simple property grid dialog that edits any config file generically and can pull in "documentation" either from an xml file or reflection.
jschell wrote: XML can be unordered or ordered.
Entirely incorrect. The XML spec says specifically that attributes and siblings are unordered and can be returned in any order the parser wants. It just so happens that every parser returns siblings and attributes in document order, but that is NOT guaranteed. If you are relying on something that the XML spec says specifically is not guaranteed, I'd hate to be you when your ops team deploys "XML v17" which has some awesome performance optimization, but no longer returns in doc order and breaks all your stuff.
The proper way to do ordering in an XML file is by using a key.
I will admit however, that it's unlikely that a parser will start returning stuff in non document order, simply because some apps rely on that incorrectly.
jschell wrote: The order however does matter when Operations/Support uses standard
difference tools to compare configuration files. Such as what they might do
when they need to install a new major version or point release and they want to
insure production machines have the same values with a new configuration file
and the old one.
What does this have to do with anything? .NET has this cool versioning thing that automagically updates your config files for you and adds in any missing attributes. Yes, I'll admit that the missing attributes may be added in a different order depending on code path (**UNLESS** you do it correctly -- in which case, the attributes will always be added in the same order).
Is that why you rolled your own .config file system? Simply so your ops team can run windiff on the files to make sure they are identical?
Seems like a proper implementation of upgrading the config files would be a better solution then re-inventing everything and having a non standard API, but thats just me.
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SledgeHammer01 wrote: Much better design.
Nonsense.
SledgeHammer01 wrote: so I usually provide an easy to use GUI for them
Which means you must STILL provide documentation. And a GUI.
So now you have increased the work and time to deliver.
SledgeHammer01 wrote: I know where you're going next... web.configs, web services, etc. don't have GUIs
So you create a GUI, and documentation for the GUI that handles multiple versions for a process that Operations/Support only uses once per install.
Thus quite a bit of additional time and cost - which is your rationalization for ignoring the fact that it rewrites the file?
SledgeHammer01 wrote: Entirely incorrect.
Something new for you to learn...
http://www.w3schools.com/schema/el_sequence.asp[^]
See the first example which says "which must contain the following five elements in order"
SledgeHammer01 wrote: which has some awesome performance optimization,
Yes the high volume tps servers that I have been delivering for the past 15 years do have measured and proven production performance abilities.
SledgeHammer01 wrote: The proper way to do ordering in an XML file is by using a key.
The proper way is to understand more about what "XML" means.
SledgeHammer01 wrote: What does this have to do with anything?
What it has to do with is documentation. Please read what I said. Trivial applications might have config values that are understood without documentation but more complex apps require substantial documentation so someone besides the original developer has any chance of understanding what the values mean, how they should be set, what the relationship between different values, etc.
SledgeHammer01 wrote: ...and having a non standard API, but thats just me.
Yes it is you, because I didn't say anything like that.
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