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Thank you, I could give this a go too, it all helps with my learning.
Can I ask what you mean by "In Form_EffectiveDate, set the OKButton property of the form to DateOKButton (this negates the need to write an event-handler for the button )"?
I clicked the form and looked through the properties but couldn't see anything relating to OKButton.
Chris Wright
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In the designer view of the form (not the code-file), click on the top of the form. In the properties windows, the form itself will now be selected. Amongst all properties of the form, you have one which is called AcceptButton (my mistake, I gave you a wrong name); set this one to the name of the OK button (you can select it). When that is done, you no longer need to write an event-handler (a method) for the button's click event; the framework will wire up everything and on click of the button the form will be hidden and return DialogResult.OK.
enum HumanBool { Yes, No, Maybe, Perhaps, Probably, ProbablyNot, MostLikely, MostUnlikely, HellYes, HellNo, Wtf }
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Wow, this is nice to know. Thank you so much, I am loving learning C# 
Chris Wright
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Phil.o did make a small mistake: highlight your button, and set the "DialogResult" property to "OK" for it to close the form and return DialogResult.OK.
The Form.AcceptButton property just tells the form that an ENTER keypress is the equivelant of clicking the button. (Form.CancelButton does the same thing, but with the ESC key.)
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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Thanks OriginalGriff.
Learning is much easier and fun when people like you guys, help people like me out. I was ripping my hair out yesterday trying to figure out how to a value from one form to another.
Is the code that Phil.o supplied classed as an event?
You mentioned above that - Delegates aren't "the best way" to pass variables back, Events are (which use delegates, but hides the complexities from you).
Chris Wright
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No - that's just using ShowDialog to display Form2, which causes the Form1 code to "freeze", waiting for the new form to close before executing any more code (this is technically called a "Modal Form" but you don't need to worry about it).
There is also Form.Show which returns immediately, and that type needs Events to "Know" when data is available for Form1 to process. Follow the link I gave you, and you'll find a download of a source project that shows it all working with Show.
If you are going to use Events - and it's a good idea, .NET is built on the buggers - then also have a look here: A Simple Code Snippet to Add an Event[^] - it makes it a lot easier to create them in your own forms and other classes.
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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You're absolutely right. Thanks for pointing it out.
enum HumanBool { Yes, No, Maybe, Perhaps, Probably, ProbablyNot, MostLikely, MostUnlikely, HellYes, HellNo, Wtf }
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If you want to pass data from Form2 to Form1. Add static string or DateTime field in Form1 then in Form2 get the value of that datepicker and assign it Form1.staticvariable.
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I want to write a PowerPoint addin that adds a button to the screen during the actual presentation time (rather than editing time) and then draws output on top of the presentation over top the presentation. The point is to pick a random person from a registered audience and display their name.
1. Is this kind of thing possible?
2. I know there are interop pages available online. Does anyone have any quick pointers as to what part of these documents I should look at for presentation event handlers (such as a slide change) and stuff like that? Perhaps how to draw a GDI+ object to a slide? (and remove that drawing upon a button click)?
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No... actually this is the correct forum. I am interested in C# addons. Not whatever that is about. There is already a tutorial on basic .NET addons but it doesn't quite cover the areas I am interested in learning about:
PowerPoint timer (addin)[^]
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I'm trying to create a query with And and Or predicates.
My question is how to form it so that I have all the ANDS, PLUS the ORs:
If this was SQL, I would do
SELECT *
FROM ValidityRules
WHERE InstrumentId = 1 AND
BaySerialNumber = 'ABC123' AND
AssayType = 'MyType' AND
(ValdityCode = 'Code1' OR
ValdityCode = 'Code2' OR
ValdityCode = 'Code3')
Note that the codes are in parens.
Here's what I have so far:
var predicate = PredicateBuilder.New<ValidityRulesEntity>();
predicate = predicate.And(x => x.InstrumentId == entity.InstrumentId);
predicate = predicate.And(x => x.BaySerialNumber == entity.BaySerialNumber);
predicate = predicate.And(x => x.AssayType == entity.AssayType);
foreach (var validityCode in entity.ValidityCodes)
{
predicate = predicate.Or(x => x.ValidityCodes.Equals(validityCode));
}
What's the right way to do this?
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.
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Hi,
This article C# 7.0 in a Nutshell - PredicateBuilder[^] seems to explain it well. Look for
"The answer is to build the parenthesised expression first, and then consume it in the outer expression ".
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That did it.
Thanks for the book ref
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.
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you're welcome.
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I have a asp form what I want if the form validation is true then the page should be refresh and all the fields should be clear and if the validation is not true the page should not be refresh and the form data should not be cleared.
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You still "refresh" on error; except, you "return" all the data, with appropriate "error info", so the user can correct.
A favorite seems to be to say there are errors and to return an empty screen so you can start over (sloppy banks and insurance companies). Oh, and don't forget to timeout in a ridiculous short amount of time; like, too short, to check some papers (the first time).
The Master said, 'Am I indeed possessed of knowledge? I am not knowing. But if a mean person, who appears quite empty-like, ask anything of me, I set it forth from one end to the other, and exhaust it.'
― Confucian Analects
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If I make a new project in Visual Studio and give it the name Welcome Program, then I see this in the code window:
namespace Welcome Program
Okay I am aware that a namespace helps organize things better and helps keep things separate, but this is not needed in a console program. But if I delete this line in a GUI program the program will not build. Is this just simply something Microsoft decided to build into their language? It has to be there when making a GUI?
And my second question is about this line:
Public Partial Class MainWindow:Window
All I know about this is that a partial class allows you to split the class definition among more than one file. This line also has to be there. What does MainWindow:Window mean? What is the purpose of the colon?
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All of your code goes into classes. Classes ALWAYS go into a namespace. You cannot have a class without it being in a namespace, even in a console app.
MainWindow is the name of your class. The ": Window" part means the class inherits from a class called "Window".
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'NameSpaces [^] control semantic scope: the context in which specific names (Classes, Methods, Fields, Properties, etc.) have meaning. They are a tool you can use to organize your code, and, when using different libraries that have duplicate names, to ensure isolation of one meaning from another (prevent name clashes).
Going a little "deeper:" we can view NameSpaces as an abstraction of an underlying code base that involves Assemblies; see this to explore this further: [^]
C# allows multiple NameSpaces in one file; other languages (ex. Java) do not.
It is very typical to use 3rd. party tools, or code libraries (dll's), and typical that you need to import code which will have their own NameSpaces. In C# Visual Studio you do this from the Solution/Project/References/Add Reference menu in the Solution Explorer.
Then, you enable the imported code to become available by adding a 'using statement with the name of the NameSpace. Member 12974235 wrote: Public Partial Class MainWindow:Window
This is the default declaration of a newly created WPF app.Quote: <global.microsoft.visualbasic.compilerservices.designergenerated()> _
Partial Class Form1
Inherits System.Windows.Forms.Form
This what the Designer.vb file in a VB app uses.Quote: public partial class Form1
C# declaration.
«Where is the Life we have lost in living? Where is the wisdom we have lost in knowledge? Where is the knowledge we have lost in information?» T. S. Elliot
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Namespaces: Dave and Bill have covered that comprehensively.
public partial class MainWindow:Window (Note that I corrected your typecase: C# is case sensitive, and "public", "partial", and class" are keywords, "Public", "Partial", and "Class" are not so you would get compilation errors with your original code).
public says that the class can be used inside and outside the containing class or namespace: if I reference your Assembly file once you have built it, I can use your class in my code.
partial you know about.
MainWindow:Window You are declaring a class: public partial class starts that, and MainWindow gives it a name. Without a name, you couldn't create an instance of the class which means you (pretty much) can't use it at all. The colon character ':' tells the compiler that this class called MainWindow is derived from an existing class - in this case the base class is called Window. This is called inheritance and you will meet this later in your course or book as it is very much fundamental to C# (and in fact to all OOPs languages). For the moment, just think of it as saying "MainWindow is a Window and I need to specify that if anything is going to work" - inheritance is one of three very important class "attributes" that you will need to learn, probably together, and they are all rather too complicated to cover in a little text box like this!
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
modified 10-Jul-19 3:27am.
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fyi: my students have responded well to the idea of a "library of blueprints," where you check out a Class (or, whatever) blueprint (declaration), and build it (instantiation). using this metaphor, you can describe the internal components (Fields, Properties, etc.) of a Class declaration as a "bill of materials and/or required tools, building skills).
mmmm ... what would a language running in .NET be without its own syntax ? a carnival ride with no admission fee ?
i'm grateful that the abomination of 'let has not snuck in to C#'s pantry, except in that execrable dialect of LINQ. :omg for that, i'll put up with the Elvis operator (#6), and new weirdness' in pattern matching now marching towards us (#7, #8).
«Where is the Life we have lost in living? Where is the wisdom we have lost in knowledge? Where is the knowledge we have lost in information?» T. S. Elliot
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APL, I suspect! 
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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Just the sight of the three letters "APL" gives me an immediate cold chill: I was in the first year of a doctoral program at UC Berkeley (long ago, as in the early '80's), and the required research component for the year ... which was supposed to make us masters of statistical inference, wizards of qualitative social science research, etc. ... was taught by a person who decided we (the doctoral students) should grok all his lectures that he chalkboarded using APL. None of us had any prior programming experience ... remember this is back in punch-card jobs and terminals connected to mainframe days; you had to go over to a building to get your print out.
The amount of mental bandwidth I wasted pretending the teaching and the APL was intelligible ! I quit the program at the end of the first year: having stuck it out to prove I was not a "quitter."
Interestingly enough, a year later I got deep into Lisp, and assembly language.
Perhaps I should thank APL for curing me of an academic career ?
«Where is the Life we have lost in living? Where is the wisdom we have lost in knowledge? Where is the knowledge we have lost in information?» T. S. Elliot
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I know the feeling - I was working for a Terminal manufacturer, just before the advent of the PC and they bought an APL company (they made APL interpreters if I recall correctly). So they wanted a APL terminal, which meant I had to sit down with these guys and work out what they actually needed. Took forever to get it all up and running on a Z80 (with 8K RAM and 32K ROM) but it worked pretty well, I think. Don't think we actually sold any, or at least I never got a single bug report ...
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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