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1. If using CreateGraphics() is not allowed, why is it there ?
the MSDN exmaple shows it's use inside a function that does not receive any PaintEventArgs:
private void AutoSizeControl(Control control, int textPadding)
{
Graphics g = control.CreateGraphics();
Size preferredSize = g.MeasureString(
control.Text, control.Font).ToSize();
control.ClientSize = new Size(
preferredSize.Width + (textPadding * 2),
preferredSize.Height+(textPadding * 2) );
g.Dispose();
}
2: I AM calling Control.Invoke() and implementing ISyncronizedInvoke interface
<pre?
if(lbsonginfo.invokerequired)
{
this.lbsonginfo.invoke(new="" scrollthreaddelegate="" his.showscrolltext));
}
<="" pre="">
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I've just spent the last 3 hours trying to debug this one without luck.
my simplified server code:
static void Main()
{
RemotingServices.Marshal(myObj, "myObj.rem");
while(true)
{
string command = Console.ReadLine();
if(command == "test") Console.WriteLine("hello");
}
}
my simplified client code:
IMyObj theServerObj = RemotingServices.Connect(typeof(IMyObj), ...);
theServerObj.DoSomething();
When I run the client and server, the client connects to the server's remote object, then calls the DoSomething method, no problems at all. If I restart the client app while still running the same server instance and run the code again, the client hangs on the .DoSomething() line. Visual Studio's debugger tells me the server is waiting for input on the Console.ReadLine method. And sure enough, if I enter "test" into the console, it writes "hello" and the client is then able to connect. To make matters more mysterious, any attempts to connect by running a client a 3rd, 4th, etc. time works without problem.
So to summarize, the code works without problem the first time a client connects. IF the client is restarted, it doesn't connect until the server gets input. If the client is restarted again (and any consecutive attempts hereafter), all works fine again.
I do use some locks in my code but from what I can tell all locks are released after the first connects; everything should still work. Anyone have any suggestions?
Judah Himango
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Are you calling RemotingServices.Disconnect after calling DoSomething? If not, the object may hang around on the server channel.
Microsoft MVP, Visual C#
My Articles
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Call disconnect on the server objects? Na, don't want to do that because I want the client to connect to that singleton, I don't want to publish a new IMyObj from the server each time.
Judah Himango
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No, on the client (after connecting and calling DoSomething). Maybe I'm not understanding your code snippets, though.
Microsoft MVP, Visual C#
My Articles
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Ok, yes, I am disconnecting all client-published objects (which I didn't mention in the code snippet). I cannot disconnect server proxy objects on the client side of course.
This is one of the strangest problems I've ever seen, given it occurs only during certain instances of the client application. Hard to debug too with multiple threads running across application and machine boundaries. :-p
Judah Himango
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Without more hints (or code) I have no idea how the objects are configured or even guess how they behave during their life time. Just dropping an object into a thread and assuming it will be "thread safe" is dangerous. Just dropping an object into the remoting framework and assuming it will be "multiple client safe" is equally as dangerous.
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You're right. It is bizaare. I think you will agree that the key piece of information is that the reconnect fails only when the main thread is blocked on the first call to Console.ReadLine. What would the Console class be doing that would have any impact on your remoting object anyway? Is DoSomething using the Console class in any way? Can you whip up the smallest program that demonstrates the problem and post the code? Maybe in the process of working on that you'll discover the problem, but if not then you'll have something complete that all of us can take a look at.
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Is there any easy way to convert .rc (C++ resource) files to .resx (C# resource) files? I have a C++ project which I'm converting to C# and don't want to have to write my own utility to convert the old resource files over.
BRCKCC
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Hi,
Where can I find a sample code for passing array or VARIANT from ATL COM control to C# .NET?
Thanks,
Alex
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Search CodeProject.
The important thing is developing your .NET code correctly. Use the MarshalAsAttribute with the appropriate UnmanagedType enumeration member. For an object[] array, you can use a myriad of choices but commonly - if you're passing an array of variants - you'll either use UnmanagedType.LPArray or UnmanagedType.SafeArray. A SAFEARRAY in unmanaged code stores information for each elements (what VARTYPE it is).
Read about the MarshalAsAttribute in the .NET Framework SDK to start. You should also read Interoperating with Unmanaged Code[^] in the .NET Framework SDK, specifically Marshalling Data with COM Interop[^]. This presents a lot of information you must understand, as well as some examples.
Microsoft MVP, Visual C#
My Articles
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Hi, I'm trying to pass a custom object to a web service as a web method parameter. For this, I had to modify the References.cs file and delete the simplified version of the class, so I can pass directly my objects.
The problem is that when I check the object in the web service, the collection that includes is empty. Do you know what can be happening?
I don`t know how to solve this.
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Diego F. wrote:
For this, I had to modify the References.cs file and delete the simplified version of the class, so I can pass directly my objects.
You will have to add some XmlSerializer attributes for that to work I think. See how the other members are handled, and be warned, never edit generated code.
top secret xacc-ide 0.0.1
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I tried using object arrays, but the only way I could make it work was using a Dataset. I added a method that returns a DataSet with the attributes mapped, and it works without modifying the References.cs file.
I think I'll leave now, because it is taking so long.
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What do I have to do, in order to hand over a parameter to a function, which was compiled before by (ICodeCompiler CreateCompiler())?
I know, that I need the „InvokeMember“, which only permits the type Object, but I need the type HttpContext.
What do I do wrong, or is there something I forgot, or is there another way?
Yours,
Patrick
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Every type in .NET derives from System.Object, so when a parameter, properties, etc. takes an Object, you can pass anything (including value types like structs, the primatives, etc., but that performs boxing and unboxing which is a performance penalty, mind you). This is VERY important to understand.
This means that every type inherits the members of Object and may override some (like ToString, GetHashCode, and Equals).
Microsoft MVP, Visual C#
My Articles
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I would like to create a logon page, but I didn't want the names store in a COTs datebase. Can I create a file store the names in it, then compare want is in the file to to want the user types in the textboxes?
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bthumber wrote:
Can I create a file store the names in it, then compare want is in the file to to want the user types in the textboxes?
Yes, if you have a specific question in terms of C# feel free to post it.
- Nick Parker
My Blog | My Articles
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The next question is how do you compare those two strings?
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bthumber wrote:
The next question is how do you compare those two strings?
Read about the String.Compare[^] method.
string s = "Nick";
string t = "Parker";
if(string.Compare(s, t) == 0)
Console.WriteLine("Equal");
else
Console.WriteLine("Not equal");
- Nick Parker
My Blog | My Articles
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Hello, I'm creating a slider-like control based in UserControl. Since the UserControl can't receive keyboard events (At least not that I manage to catch), I use a button as the slider handle since that can receive focus (I want to be able to run the slider up/down with the keys that's what I need the key focus for...)
First I tried listening to the KeyDown event from the button, but that doesn't get fired, only the KeyUp.. Has it something to do with that the button filters away these events and fires Click instead?
So I grab the button and check what messages it receives with spy++, and it says both WM_KEYDOWN and WM_KEYUP (repeated WM_KEYDOWN when key is held down as would be expected). So I override the button and it's wndproc to listen for these events, and also override the onpaint to get rid of the 'click' effect that I don't want.
BUT: the wndproc doesn't reveice any WM_KEYDOWN (0x0100) messages. So where are they going and how can I get them? Is there some kind of preprocessmessage-like function that receives and filters these events?
Or is there another control I can override instead of a button, that can get keyboard focus. Also, the button still has it's click behaviour that I don't want...
Can anyone help me with the right way to go??
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A UserControl is for composite controls (i.e., controls made-up of other controls). It's not really a good base class in this case, and is designed to receive notifications from its children.
There are lots of articles here on CodeProject about custom slider controls. I recommend taking a look at some to get some better ideas (without going into a long, unnecessary discussion here) to help you along.
http://www.codeproject.com/info/search.asp?cats=3&cats=5&searchkw=slider[^]
Microsoft MVP, Visual C#
My Articles
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Hi,
I've got a custom control (button using rounded .gif image with transparent corners) on top of a panel. The panel has a .wmf file as its background image. When I place my control on my panel the background COLOR of the panel shows through my transparent corners instead of the background IMAGE of the panel. If I make the panel's background color transparent the background color of the form shows through the corners.
Is there any way to force the panel's background image to show up in the transparent sections of my control?
thanks!
Deanna
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A little more info... In my control's OnPaint I'm trying to clear the background using :
g.Clear(Parent.BackColor); where g is my Graphics object
I'm wondering if that line is incorrect.
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The best way is to use clipping regions. Transparency is only supported in Win2K and newer (flavors of Windows NT only; i.e., Windows ME does not support transparency), so if you want to support all .NET-supported Windows platforms, use clipping regions.
You can do this a number of ways, such as overriding OnPaint and setting PaintEventArgs.Graphics.Clip to a Region that contains only the portions to draw. You can construct an adequate Region using the GraphicsPath class in the .NET BCL.
Clipping regions is how most applications handle non-rectangular windows (controls are windows, too). It works on any Windows platform.
You can find a nice little library to assist you - even graphically in VS.NET - written by a Microsoftie at http://windowsforms.net/articles/usingregionmastercontrols.aspx[^].
Microsoft MVP, Visual C#
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