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I have another question. I'm trying to loop through all the textboxes on a
web application. The snippet is below
//foreach(WebControl ctr in Page.Controls)
foreach(Control ctr in Page.Controls)
{
if(ctr is TextBox)
{
TextBox t = (TextBox)ctr;
t.BackColor = Color.AliceBlue;
t.ReadOnly = false;
}
}
Would you please tell me why it does not work?
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caheo wrote:
Would you please tell me why it does not work?
What error do you get? Does it just not update the colours? or does it throw an exception? or just does not compile?
That information is usually an excellent start to figuring out why something does not work.
"You can have everything in life you want if you will just help enough other people get what they want." --Zig Ziglar
The Second EuroCPian Event will be in Brussels on the 4th of September
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
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It does not give any error. The reason I ask is there are quite a few TextBoxes on the GUI, after doing comparision at the if statement it skips and do the next iteration. Seems to me the if statement never reaches.
foreach(Control ctr in Page.Controls)
{
if(ctr is TextBox) <- it does comparision but never gets inside the if-statement
{
TextBox t = (TextBox)ctr;
t.BackColor = Color.AliceBlue;
t.ReadOnly = false;
}
}
Regards
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Personally I would have written it like this:
foreach(Control ctr in Page.Controls)
{
TextBox t = ctr as TextBox;
if(t != null)
{
t.BackColor = Color.AliceBlue;
t.ReadOnly = false;
}
}
"You can have everything in life you want if you will just help enough other people get what they want." --Zig Ziglar
The Second EuroCPian Event will be in Brussels on the 4th of September
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
My Blog
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Are you sure your TextBoxes aren't in other naming containers (like the Panel)? Just because all the TextBoxes appear to be in the page, doesn't mean they're direct children of the page. You need to use a recursive methods like so:
private void SetReadOnly(Control parent, bool readOnly)
{
if (c != null)
{
foreach (Control child in parent.Controls)
{
if (child is TextBox)
{
TextBox tb = (TextBox)tb;
tb.BackColor = Color.AliceBlue;
tb.ReadOnly = readOnly;
}
SetReadOnly(child, readOnly);
}
}
}To call this, just pass the Page reference to this property:
SetReadOnly(Page, false); For more information, see the INamingContainer interface documentation in the .NET Framework SDK.
Microsoft MVP, Visual C#
My Articles
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Since you don't say what happens or what doesn't happen or give any kind of error message (other than "it's broke"), it's difficult to say what you're problem is. I can take a guess and say that you might be having trouble with the if statement, so how about making your if statement look like this:
foreach(Control ctr in Page.Controls)
{
if(ctr.GetType().Equals(GetType(TextBox)))
{
TextBox t = (TextBox)ctr;
t.BackColor = Color.AliceBlue;
t.ReadOnly = false;
}
}
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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There you go again, Dave! 
GetType is a VB.NET operator equivalent to C#'s typeof operator.
Microsoft MVP, Visual C#
My Articles
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DAMN!  I can't keep anything straight nowadays! 
Now where did my mouse go...
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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See what VB.NET is doing to you? Break away now or be doomed... 
Microsoft MVP, Visual C#
My Articles
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You aren't looping through all the controls on the form, just the direct children of the Page. To get all, you would need to recursively search through the control. Also make sure you are doing this in the PreRender event so you can make sure that all the controls have been created.
The architect has placed his bets,
but the odds are long
-Poster Children
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Hi, I need to know when the user press the period key in the numpad.
In the keys enumeration I have Keys.NumPad1 .... Keys.NumPad9.
Im using the keyup event and its e.Keycod argument.
What Keys enumeration value I shuold to use? 
Gracias!
La realidad no es más que impulsos eléctricos del cerebro - Morpheus
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This is documented, though not very clearly - so I offer another suggestion...
If you're not sure about something, a really quick method is to write a small test app. I threw the following together in under a minute:
using System;
using System.Windows.Forms;
public class Test : Form
{
static void Main()
{
Application.Run(new Test());
}
protected override void OnKeyDown(KeyEventArgs e)
{
base.OnKeyDown(e);
Console.WriteLine(e.KeyCode);
}
}Running it yields that the decimal point on the numpad is Keys.Decimal and that the period is Keys.OemPeriod. Writing simple test apps is very handy - something to keep in mind.
Microsoft MVP, Visual C#
My Articles
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Thank you. Its a good sugestion.
La realidad no es más que impulsos eléctricos del cerebro - Morpheus
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I wanted to create my own Menu type class for use with a drop down button so that when you click the button a window can pop up that will contain some other controls. At first I thought I could do it with a stripped down form, but I realized that when I create the form it will always be activated and take focus from my main window (I don't want this to happen). So what I'm wondering is what are similar things like context menus or the dropdown portion of the combobox based on? Or is it possible to make a form that won't steal the focus?
Thanks,
Jesse
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Windows Forms controls (as well as many classes in the .NET Framework Class Library (FCL) encapsulate native APIs. You need to research and understand the Windows APIs and common controls to do what you want. For instance, read the Windows Controls[^] and Windowing[^] sections in the Platform SDK. You need to understand window handles, styles, and message pumps.
You might try searching CodeProject for existing managed samples (in C#, VB.NET, whatever - it all gets compiled to roughly the same thing), but you'll most likely find the majority of samples in VC++ or MFC. Writing custom menu bars and toolbars in VC++ or MFC is very common and there are plenty of samples both here on CodeProject and on sites like CodeGuru[^].
For example, you'll want to override the protected CreateParams property in your control derivative and use the WS_POPUP (0x80000000) window style. See the Platform SDK for more details about that, which should give you some idea of where to start.
Microsoft MVP, Visual C#
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Hi
I have been tring to cause a script timeout from an aspx page
(to understand the process better...)
I have tried these 3 ways but none worked:
A) on Page_Load -
Server.ScriptTimeout = 10;
B) in web.config -
<HTTPRuntime executionTimeout="10">
C) IIS->Default Web Page->Properties->Home Directory->Configurations->
set ASP Script timeout to 10
I have put a long file copying to make sure the page is not returned from the server before the script time out but still my page does not cause a script timeout.
Could Anybody help me,
Thanks.
Eli
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Does anyone know how to copy a fixed string buffer directly into a struct in 50 lines or less? Can this be done in C#? I have been looking all over and I am unable to find a good example of this using c sharp. In vb6 I would use the CopyMemory function to do this but I can't in sharp.
I want to take this struct(not sure even if it the correct layout) and
pass my buffer string into it.
string buffer = "abcdefgh2655501";
[StructLayout(LayoutKind.Explicit)]
public struct MyStruct
{
[FieldOffset(0)] public string fname;
[FieldOffset(4)] public string lname;
[FieldOffset(8)] public string phone;
}
Diego
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dgiljr wrote:
Does anyone know how to copy a fixed string buffer directly into a struct in 50 lines or less?
Why don't you tell us what you're trying to accomplish? Do you need to marshal this struct to unmanaged code, or just parse it? If you need to marshal it, then you also need to declare the character encoding. A field length of 4 bytes for each field is only 2 characters using the native Unicode encoding of .NET (strings are stored and manipulated using Unicode). You should also use the MarshalAs(UnmanagedType.ByValTStr), and don't forget to set the CharSet field on the StructLayoutAttribute accordingly. Again, though, 4 bytes still isn't enough.
Now, to marshal this struct to unmanaged code as string reference, what you have would work on a 32-bit processor. Typically, you want to use LayoutKind.Sequential and make sure your fields are declared properly (like unmanaged long is actually a managed int - both 32 bits). Then, on a 64-bit OS (when .NET 2.0 is released that supports 64-bit processors) the string references would actually be 64-bits (the size of a handle, or unsigned int).
If you just need to parse a string, either use the String class methods (like Substring) or use a StringReader (see the StringReader.Read(char[], int, int) method in teh .NET Framework SDK). There's other ways, as well; after all, this is just simply string parsing.
Microsoft MVP, Visual C#
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I need to send and receive unmanaged strings to a Unix box using sockets and because of our buffer protocols changing from time to time the best way to manage this is by using structs. Currently if I have 30 fields defined in my buffer with fixed lengths and I change the field length for field number 15 I now I have to go into all the properties for fields 16 to 30 and change their substring starting points which is a hassle. I find that using structs eliminates all that hassle since it will automatically adjust itself in that scenario. My character set will have to be unicode but I am struglling with the idea of Marshaling and I can't seem to find a good code example of this for c sharp. I have seen examples of copying structs to structs and arrays to structs but not strings to struct casting.
Diego
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Again, this is still a simple parsing problem. Do read about the UnmanagedType.ByValTStr, though. Using that in your MarshalAsAttribute for fields and setting the SizeConst field means you don't even have to change the offsets - another reason to use LayoutKind.Sequential.
This still doesn't make a whole lot of sense, though. How is it easier to pass a string as a struct? Just encode the string and pass the byte[] array, since a byte[] is always the same on any platform (not taking into account endianess). Just make sure you use the same encoding on both ends. The HTTP protocol, for example, specifies the encoding in the HTTP headers.
Microsoft MVP, Visual C#
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Right now our code is in vb6 and I have a type defined as:
' This is the buffer passed in from my winsock control.
buffer = "abcdefgh1234567"
type mytype
fname as string * 4
lname as string * 4
phone as string * 7
end type
dim mt as mytype
up = VarPtr(mt)
' Copy buffer to struct
CopyMemory ByVal up, ByVal StrPtr(buffer), LenB(buffer)
debug.print mt.fname
If I needed to modify lname to make it 5 bytes all I have to do is change it to 5 in only one place - the struct.
If I substring the buffer I would have to change the starting position for phone to have one byte more and then the same for every field after phone. This is why substring is a hassle here - especially for a proprietary protocol that has dozens and dozens of fields. I basically want to mimic the vb example above in C sharp.
Diego
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Again, you don't want to use FieldOffsetAttribute, because that would cause you to have to change the offset for each field. If you read the documentation, it is the offset from the beginning of the structure - not the last field.
AS I said, though, this can still be done using the Marshal class. See the Marshal.PtrToStructure method, for example. To get the IntPtr for the string, use GCHandle.Alloc.
There's one problem you're also overlooking: in VB6 and below, strings are not null terminated. In most Windows APIs - including the .NET Framework - strings are null terminated.
So, lets say you use UnmanagedType.ByValTStr that I mentioned before. While Marshal.PtrToStructure would honor the StructLayoutAttribute, the problem is that the character sequences in your string will not be delimited with null characters. You need to write a work-around for this, or implement an ICustomMarshaler and implement the work-around.
Stil, though, nothing says that simply parsing the string has to be difficult. When you read in a substring, use the index and get the next substring starting from that index. This still allows you to change one line without changing others.
Consider the following example:
public struct Phone
{
public int CountryCode;
public int AreaCode;
public string Number;
public static Phone Parse(string value)
{
Phone p = new Phone();
int index = 0;
p.CountryCode = int.Parse(value.Substring(0, 1); index += 1;
p.AreaCode = int.Parse(value.Substring(index, 3); index += 3;
p.Number = value.Substring(index, 7);
}
}See? All relative. You just need to change the length of the string to grab with String.Substring plus the index addition/assignment right operand.
To recap, though, the reason what you had worked in VB6 is because strings are null-terminated, allow for a sequence of characters to be packed in a struct. While conceptually the same is possible, it's the null termination that will cause you a problem.
With some fanagling, you could get it to work. See the .NET Framework SDK documentation for the Marshal class for lots of helpful methods.
And remember, the FieldOffsetAttribute won't work for what you want because it'll force you to go through and chance all the preceeding offsets if you change one offset since they are the offset from the beginning of the struct (offset 0, of course).
Microsoft MVP, Visual C#
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Heath,
Thanks for all your help. I finally figured out how to cast a string into a struct thanks to your help. Here is the code I finsally came up with.
class Class1
{
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
public struct MyStruct
{
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=4)] public string fname;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=4)] public string lname;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=7)] public string phone;
}
public static void Main()
{
string buffer = "abcdefgh2223333";
IntPtr pBuf = Marshal.StringToBSTR(buffer);
MyStruct ms = (MyStruct)Marshal.PtrToStructure(pBuf,typeof(MyStruct));
Console.WriteLine("fname is: {0}",ms.fname);
Console.WriteLine("lname is: {0}",ms.lname);
Console.WriteLine("phone is: {0}",ms.phone);
}
}
I am going to post this bit of code on the site.
Diego
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I wanted a multiline textbox control with possibility of giving different background colors to the lines. for eg:- if the first line has a white background the second line should have a yellow background etc. Please help
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