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hi..
im trying to populate my checklistbox with a column that im getting from a database.
well i get the column and store in a datatable my question how do i populate whats in the datatable into the checklistbox...pls help...
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Set the DataSource propoerty of CheckListBox property to your datatable and its DisplayMember , name of your column.
And don't cry , there is always a solution. 
Mazy
"A bank is a place that will lend you money if you can prove that you don't need it." - Bob Hope
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well setting the property is another problem...im using Visual Studio .Net 2003 and it looks like they haved scraped these properties off checklisbox..i wonder why...i tought the more adavanced things got the more easier it got for us...sighhhhh...
 ... i'll stop once i get this prblem fixed...hehehe
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ASGill wrote:
it looks like they haved scraped these properties off checklisbox
 Although I donn't have VS.NET 2003 but how is this possible? I can understand it.
Anyway, can't you set it programiically? Like this:
checklistbox1.DataSource = mytable;
checklistbox1.DisplayMember = columnname;
Mazy
"A bank is a place that will lend you money if you can prove that you don't need it." - Bob Hope
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Hi Mazy...( yeah i know its kinda shocking..  )
anyways... i got the adding part working, its working alrite, but with a flaw...and i have got no clue of what so ever abt why its happennin
<br />
private void frmPrescription_Load(object sender, System.EventArgs e)<br />
{<br />
try<br />
{<br />
oleDbConnection1.Open();<br />
<br />
oleDbDataAdapter1.SelectCommand.CommandText = "SELECT [Med Name] FROM Pharmacy";<br />
<br />
oleDbDataAdapter1.SelectCommand.ExecuteNonQuery();<br />
<br />
oleDbDataAdapter1.Fill(dataSet1);<br />
<br />
for(int i = 0; i < dataSet1.Tables[0].Rows.Count; i++)<br />
{<br />
this.checkedListBoxName.Items.Add(dataSet1.Tables[0].Rows[i][4], false); <br />
}<br />
}<br />
catch (Exception LoadError)<br />
{<br />
MessageBox.Show(LoadError.ToString());<br />
}<br />
finally<br />
{<br />
oleDbConnection1.Close();<br />
oleDbConnection1.Dispose();<br />
}<br />
well when it adds the item, it adds it twice...i.e i have the value "Aspirin" in the column in the table...its s'pose to display it only once but i get
1. Aspirin //numbers represent checkboxes
2. Aspirin
3. Piriton
4. Piriton
and so on.....all of the values are added twice..whats wrong...
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Hi
I 'm wondering why you :
oleDbDataAdapter1.SelectCommand.ExecuteNonQuery();
oleDbDataAdapter1.Fill(dataSet1);
you olny need to oleDbDataAdapter1.Fill(dataSet1);
why did you write
oleDbDataAdapter1.SelectCommand.ExecuteNonQuery();
first .?
bye.
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As Masud said remove oleDbDataAdapter1.SelectCommand.ExecuteNonQuery();
line then you call fill method set the DataSource and DisplayMemerb ofCheckListBox as I told you.
Mazy
"A bank is a place that will lend you money if you can prove that you don't need it." - Bob Hope
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aight....got it fixed...
the oleDbDataAdapter.SelectCommand.ExecuteNonQuery(); was a mistake...the code i posted was an earlier version of it...sorry...
thx for the help guys
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I'm reading a YCbCr image byte by byte from the parallel port and all I want
to do is to display the image on the screen using C#. I wonder how I can do
it. Ways that I can think of include:
1. Convert to RGB and construct a Bitmap object (Is there any simple way to
do the conversion?)
2. Construct an Image object with YCbCr pixel format (I should that Image
has a Flags property which includes YCbCr color space. But how can I make
use of this?)
A thousand thanks.
Yawen
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I'd like to use my PC's serial port to communicate with my IC which uses the I2C standard. Is there any class or functions that I can use to do that?
Thanks very much.
Yawen
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You should search CodeProject for a number of articles describing serial communications in .NET. Since the .NET base class library does not provide this functionality, there are many libraries available to help you.
If you download the VB.NET Resource Kit from http://msdn.microsoft.com/vbasic/vbrkit[^], you can use Sax.NET. Don't worry that it's in the VB.NET RK. In the .NET Framework, all source compiles to IL that's placed in modules and into assemblies. Any .NET language can use an assembly written in any other .NET language because they all compile to IL.
Microsoft MVP, Visual C#
My Articles
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Suppose I have Class:
1) class Shape{}
2) class Square : Shape {}
3) class Circle : Shape {}
and Method:
1) void f(Shape s){}
2) void f(Square s){}
3) void f(Circle c){}
Now, I declare 3 variables:
1) Shape a1 = new Shape();
2) Square a2 = new Square();
3) Circle a3 = new Circle();
If I call f(a1), it will go to method 1.
If I call f(a2), it will go to method 2.
If I call f(a3), it will go to method 3.
Right?
But If I call f((Shape)a2), it will go to method 1.
Is there anyway to make if I call f((Shape)a2), and it will go to method 2 directly?
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I'm not sure what you want to do, but here's my two cents:
If your parameter is cast to Shape, and Square is derived from Shape, first the runtime / compiler will look in the class Square if it can find a method with the f(Shape s) signature.
Since it can only find the f(Square s) method, it'll go up on class (which is Shape) and there it WILL find the wanted menthod.
If you want class Square to have it's own f(Shape s) method, you'll have to overload the original one, i.e. recreate the f(Shape s) method in the Square class...
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Actually the method f is not a member method of Shape, Square, Circle.
It is static method of another class, which can takes "Shape" or "Square" or "Circle" as parameter.
Actually, what I am doing now is:
public static f(Shape s){
if (s is Square){
f((Square)s);
}
else if (s is Circle){
f((Circle)s);
}
}
public static f(Square s){
MessageBox.Show("It is a Square"):
}
public static f(Circle s){
MessageBox.Show("It is a Circle"):
}
It works, but the problem is when there is a lot of derived class, the f(Shape c) method will be very bulky.
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I Really don't understand what you're trying to do here. WHy define a static class where you process objects that have nothing to do with that class (it is static, so the class that holds the static method can't do anything with the passed object???? The whole idea behind OO is that you put things that belong together in a class, so if you want to edit a Square, use the f in Square.
Then, there's the "virtual" keyword as well, if you define f as virtual in Shape and pass it a Square it will try to locate the f method in Shapes subclasses.....
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Why write 3 different overloads of the method if you are casting all the parameters to Shape anyway.
The whole point of method overloads is that you can theoretically pass it any kind of Shape derived object(or whatever for that matter) and the runtime will work out the right overload to call. Maybe I am not clearly understanding what you are trying to do, but this seems a little bit silly.
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Seems to me you have some misunderstanding about the concepts:
First of all the methods "f" belong to which class(es)?
Second: The typecast (shape)a2 is redundant (don´t remember if it is syntactically ok but if so it has nonsense anyway)a2 is a Square so it IS a Shape anyway
how inheritance and polymorphism works...
I guess you wanted to do something like this:
You have the classes and their respective methods:
class Shape<br />
{<br />
virtual void f{} to treat the Shape object (Whatever it be) who owns it<br />
}<br />
<br />
class Square : Shape <br />
{<br />
override void f{}
<br />
}<br />
<br />
class Circle : Shape <br />
{<br />
override void f{}
}
if you do
Shape a1 = new Shape();
Square a2 = new Square();
Circle a3 = new Circle();
Logically,
a1.f() will call the Shape´s f method; a2.f() the Square´s, etc
BUT ALSO if you do this....( and that´s the nice part)
Shape a1 ;<br />
Square a2 = new Square();<br />
Circle a3 = new Circle();<br />
a1= a2;<br />
a1.f();
a1= a3;<br />
a1.f();
which is something similar to what you said and is the usual way in which these kind of things are accomplished
This happens because the fmethod is declared virtual in Shape class an is overriden in the child classes otherwise, if they weren´t virtual then the calls of a1.f() always would call the Shape´s f method
Notice this approach is specially useful in this case
Class TestShapes{
void DoSomethingWithShapes(Shape s)
{
s.f();
//it will call the proper f method regarding if s is in fact a Square or a Circle or a general Shape (if this class is conceived to have instances ,thing that generally shouldn´t be taht way)
}
}
Maybe it helps
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Hello all,
My requirement is to add icons to the ContextMenu items. Any ideas how this can be achieved using C# ? There are lot many articles about how to associate icons with menus but none talk about context menus. Any help would be appreciated.
Thanks and regards,
Amit
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In the standard Contextmenu you can't add an Image. You'll either have to write a derived class with it's own OnDraw method or build an Enxtender.
Or you download one of the existing open source menu / Context Menu systems, like Magic Library or Sandbar...
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I am writing a form-based program with 2 forms: main & child.
The main form call the child form as:
frmChild child = new frmChild();
child.ShowDialog();
The problem is that in the child form, I want to change some properties of the main form (like button.Text, labels, etc). I also want to call some functions declared in the frmMain class.
I tried to use the Intelli Sense of VS in child, but when I type frmMain., it doesn't show up both the form main controls and the public functions declared in the frmMain class.
Can anyone intruct me how to do this ?
Thank you very much for your help.
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assume your parent forms class is "MyParentForm"
what you want to do in your child for is this:
<br />
MyParentForm frmParent = (MyParentForm)this.Parent<br />
this way you get to all the properties and public fields/methods of your parent form
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Sorry but it doesn't work at all.
VS didn't complain anything during compilation. However, during runtime, I got an exception saying:
Object reference not set to an instance of an object.
The watch window shows that frmParent (in your example) is an undefined value.
============
assume your parent forms class is "MyParentForm"
what you want to do in your child for is this:
MyParentForm frmParent = (MyParentForm)this.Parent
this way you get to all the properties and public fields/methods of your parent form
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when you declare the child form in the parent form you must initialize the parent property of the child form before calling show() or showdialog()
EG. ChildForm frm = new ChildForm() ;
frm.parent = this ;
frm.ShowDialog() ;
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The Parent object is not available in the Constructor yet (because it won't be set until the ShowDialog method is called). I usually set my references to the parent form in the Layout Event and add a LayoutCalled bool to the class so the references will only be set once....
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Thanks for your advice, gurus
It's working now with a few tweaks.
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