Drawing a line in control - vanishes? - C# Discussion Boards

Re: Calling a windows form

Shoaib Hussain2-Jun-07 1:45

Shoaib Hussain

2-Jun-07 1:45

do you know the names of all form in advance?

Re: Calling a windows form

hosam Taji2-Jun-07 1:46

hosam Taji

2-Jun-07 1:46

Yes Thats Exactly What I Want How To Use The Refliction in this case

Hosam Taji

Re: Calling a windows form

Shoaib Hussain2-Jun-07 1:31

Shoaib Hussain

2-Jun-07 1:31

simply ask thanks if it works

Re: Calling a windows form

Christian Graus2-Jun-07 1:35

Christian Graus

2-Jun-07 1:35

You could use reflection, or if the collection of names is known, use the approach that was given by someone else. Personally, if I had a known collection, I'd be storing an enum, not strings.

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: Calling a windows form

hosam Taji2-Jun-07 1:49

hosam Taji

2-Jun-07 1:49

This The Code
Form frm = new Form();

Assembly LocalApp;
string man = treeView1.SelectedNode.Name;
MessageBox.Show(man);
LocalApp = Assembly.LoadFrom(man);
???

Re: Calling a windows form

Christian Graus2-Jun-07 1:52

Christian Graus

2-Jun-07 1:52

hosam Taji wrote:
Assembly LocalApp;
string man = treeView1.SelectedNode.Name;
MessageBox.Show(man);
LocalApp = Assembly.LoadFrom(man);

I don't know what any of this means ? I mean, what's in the treeview ? Form names, found via reflection ?

Re: Calling a windows form

Ravi Bhavnani2-Jun-07 3:13

Ravi Bhavnani

2-Jun-07 3:13

This is off the top of my head and doesn't include any error checking.

Assembly asm = System.Reflection.Assembly.LoadFrom ("myAssembly.dll");
Type t = asm.GetType ("MyNamespace.MyForm");
ConstructorInfo constructor = t.GetConstructor (new Type[] {});
MyNamespace.MyForm form = constructor.Invoke (null) as MyNamespace.MyForm;

/ravi

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Drawing a line in control - vanishes?

BlueChippy2-Jun-07 0:25

BlueChippy

2-Jun-07 0:25

I'm guessing I've done something stupid but...

I'm new to Drawing2D, but I want a simple user control that is basically blank but will display (draw) a line when I click a button on a form.

I have a method DrawLine() in the control to draw the line using this.CreateGrapics() etc.
I have a button, on the form that implements the control, which calls control1.DrawLine().

The line DOES draw...briefly...but then vanishes?
I've tried stepping through, and the control draws the line as expected but then seems to lose it immediately.

I've overridden OnPaint, but not sure what to put in it other than base.OnPaint(e).

Any help very gratefully received.

Re: Drawing a line in control - vanishes?

Christian Graus2-Jun-07 0:55

Christian Graus

2-Jun-07 0:55

BlueChippy wrote:
I've overridden OnPaint

Great

BlueChippy wrote:
but not sure what to put in it

Basically you need to draw onto the graphics object that's passed in through e.Graphics, instead of calling CreateGraphics ( which is only useful for temporary stuff that you want to disappear the next time you call Invalidate().

Re: Drawing a line in control - vanishes?

Guffa2-Jun-07 0:57

Guffa

2-Jun-07 0:57

In OnPaint you should do the actual drawing. Whenever the control needs to be redrawn, the Paint event is used.

If you draw anything outside of the Paint event, it will just be drawn on the screen at the location where the control happens to be. Whenever the control needs to be redrawn it will redraw the screen and wipe out whatever you drew.

Also, in the Paint event you get a graphics object that is clipped to the coordinates that should be redrawn. This ensures that you don't draw outside the area that you are supposed to. If another window is partially covering your control, that is handled by clipping in the graphics object. If you create your own graphics object for the screen it will not be clipped, and you risk drawing over other windows.

---
single minded; short sighted; long gone;

Re: Drawing a line in control - vanishes?

BlueChippy2-Jun-07 1:34

BlueChippy

2-Jun-07 1:34

So, my OnPaint() should call the DrawLine() method?
In which case, how do I get the button on the form to call the OnPaint() of the control? Will control1.Refresh() do it?

Sorry for the stupid questions! lol

Re: Drawing a line in control - vanishes?

Christian Graus2-Jun-07 1:37

Christian Graus

2-Jun-07 1:37

You should override the button's onpaint event.

You can never call an OnPaint, you can just call Invalidate() to tell Windows to redraw a control.

using list object as a public property in custom control

Shoaib Hussain2-Jun-07 0:06

Shoaib Hussain

2-Jun-07 0:06

I have created a Serializable class named "Student".

[Serializable]
public class Student
{

}

Also created a custom user control.

then i used the list<student> in the custom user control.

public class myControl : UserControl
{
List<student> students;

public List<student> Students
{
set
{
students = value;
}
get
{
return students;
}
}
}

the controls is performing exact and there is no any compilation error.
but if i use this control on any form then designer view of that form vanished out and display this error.

Object of type 'System.Collections.Generic.List`1[WindowsControlLibrary1.Student]' cannot be converted to type 'System.Collections.Generic.List`1[WindowsControlLibrary1.Student]'.

Kindly help that why the designer view of this form vanished out.

Re: using list object as a public property in custom control

mikker_1232-Jun-07 16:46

mikker_123

2-Jun-07 16:46

Code you gave doesn't tell much, for example I don't see any relation with UserControl and Student class. It could be possible that you initialize student class in Control constructor (use Load event instead and use if (!DesignMode) { <initialization code=""> }), or that you have two Student classes...

So please provide more code (like complete definition of both classes).

P.

Serialization inside Singleton

LudoStroetenga1-Jun-07 23:05

LudoStroetenga

1-Jun-07 23:05

Hello,

I've got a singleton Settings Class and implemented the Serialization. I can write the object to a file, read the object from file. this all works rather well except for the tiny inconvieniance that i have to create a new instance of my settings class, while i would like to read the file to the already excisting Settings.Instance.

in short..

i have a Singleton class that has methods for writing itself to disk (settings.set)
// [Serializable] public sealed class Settings : ISerializable

is there a elegant way for this class to read itself from disk.

my complete code so far. (not yet polished)

<br />
	/// <summary><br />
	/// Description of settings.<br />
	/// </summary><br />
	[Serializable] public sealed class Settings : ISerializable<br />
	{<br />
		Logging logevent = Logging.Instance;<br />
<br />
		// ---------------------------------------------------------------<br />
		// -- general properties<br />
		// ---------------------------------------------------------------<br />
		string logFilePath = "";<br />
<br />
		public string LogFilePath {<br />
			get { return logFilePath; }<br />
			set { logFilePath = value; }<br />
		}<br />
		string logFileName = "";<br />
		<br />
		public string LogFileName {<br />
			get { return logFileName; }<br />
			set { logFileName = value; }<br />
		}<br />
		string language = "";<br />
		<br />
		public string Language {<br />
			get { return language; }<br />
			set { language = value; }<br />
		}<br />
		// ---------------------------------------------------------------<br />
		<br />
	    SerializationInfo info;<br />
     	StreamingContext context;<br />
<br />
		private static Settings instance = new Settings();<br />
<br />
		public static Settings Instance {<br />
			get {<br />
				return instance;<br />
			}<br />
		}<br />
<br />
		private Settings()<br />
		{<br />
		}<br />
<br />
		#region Serialization methods<br />
		//Deserialization constructor.<br />
		private Settings(SerializationInfo info, StreamingContext context)<br />
		{<br />
<br />
			// ---------------------------------------------------------------<br />
			// -- general properties<br />
			// ---------------------------------------------------------------<br />
			this.logFilePath 	= (string)info.GetValue("logFilePath", 	typeof(string));<br />
			this.logFileName 	= (string)info.GetValue("logFileName", 	typeof(string));<br />
			this.language 		= (string)info.GetValue("language", 	typeof(string));<br />
			// ---------------------------------------------------------------<br />
		}<br />
<br />
		//Serialization function.<br />
		public void GetObjectData(SerializationInfo info, StreamingContext context)<br />
		{<br />
			this.info = info;<br />
			this.context = context;<br />
<br />
			// ---------------------------------------------------------------<br />
			// -- general properties<br />
			// ---------------------------------------------------------------<br />
		    info.AddValue("logFilePath", 	this.logFilePath);<br />
		    info.AddValue("logFileName", 	this.logFileName);<br />
		    info.AddValue("language", 		this.language);<br />
			// ---------------------------------------------------------------<br />
		}<br />
		#endregion<br />
<br />
		#region Reading and Writing Settings object to file stream.<br />
		public void ReadFromFile()<br />
		{<br />
			ReadFromFile(System.Windows.Forms.Application.StartupPath);<br />
		}<br />
<br />
		public void ReadFromFile(string path)<br />
		{<br />
		    string SettingsFile = path + "\\settings.set";<br />
			if (File.Exists(SettingsFile))<br />
			{<br />
			    System.Console.WriteLine(SettingsFile);<br />
				            <br />
				//Open the file written above and read values from it.<br />
				Stream stream = File.Open(SettingsFile, FileMode.Open);<br />
				BinaryFormatter bformatter = new BinaryFormatter();<br />
				    <br />
				Settings tmp = Settings.Instance;<br />
				<br />
		        try <br />
		        {<br />
					tmp = (Settings)bformatter.Deserialize(stream);<br />
		        }<br />
		        catch (SerializationException ex) <br />
		        {<br />
    	              logevent.write("Class Settings 'ReadFromFile' - error : " + ex.Message);<br />
		            throw;<br />
		        }<br />
		        finally <br />
		        {<br />
		            stream.Close();<br />
		        }<br />
				stream.Close();<br />
			}<br />
		}<br />
		<br />
		public void WriteToFile()<br />
		{<br />
			WriteToFile(System.Windows.Forms.Application.StartupPath);<br />
		}<br />
<br />
		public void WriteToFile(string path)<br />
		{<br />
			string test = path + "\\settings.set";<br />
			<br />
			Stream stream = File.Open(test, FileMode.Create);<br />
			BinaryFormatter bformatter = new BinaryFormatter();<br />
			         <br />
			Settings tmp = Settings.Instance;<br />
<br />
	        try <br />
	        {<br />
	            bformatter.Serialize(stream, tmp);<br />
	        }<br />
	        catch (SerializationException ex) <br />
	        {<br />
	        	logevent.write("Class Settings 'WriteToFile' - error : " + ex.Message);<br />
	            throw;<br />
	        }<br />
	        finally <br />
	        {<br />
	            stream.Close();<br />
	        }<br />
		}<br />
		#endregion<br />
	}<br />

Ludo Stroetenga

RichTextBox blinking

the_yeast1-Jun-07 22:40

the_yeast

1-Jun-07 22:40

Hi!

I've got an issue with RichTextBox. I'm formatting the text inside, indents, colours, font attributes etc. When I insert the text from the same control - it's ok. But when I do it from another one - my RTB blinks, as if repainting its contents. I've tried to change my text formatting, checked which events were fired and nothing.

Any help from you?

Thanx in advance.

Re: RichTextBox blinking

mav.northwind2-Jun-07 20:33

mav.northwind

2-Jun-07 20:33

Hi!
What do you mean by