How can I access my Mainwindow-controls from a thread? - C# Discussion Boards

yesu prakash8-Nov-10 22:12

8-Nov-10 22:12

Hi,
I have two datagridview, one is invisible. When i click the first datagridview then the other will visible, and i need to select a value from that grid. How can i drag rows in the new grid when i press down arrow?

Thankyou

Re: Datagridview

TweakBird8-Nov-10 23:59

TweakBird

8-Nov-10 23:59

Have a Look

http://www.codeproject.com/KB/webforms/DragAndDropGridView.aspx

http://www.telerik.com/community/forums/aspnet/grid/drag-and-drop-grid-rows.aspx

http://jqueryui.com/demos/sortable/#connect-lists

http://forums.silverlight.net/forums/p/164753/372597.aspx

http://themechanicalbride.blogspot.com/2009/08/new-with-silverlight-toolkit-drag-and.html

http://aspdotnetcodebook.blogspot.com/2009/04/how-to-move-selected-record-from-one.html

Replace assembly at runtime

marca2928-Nov-10 21:43

marca292

8-Nov-10 21:43

Hi,

I have a .NET C# application that contains many different assemblies. My start up project contains all assemblies as references, so when I build the application all these assemblies are copied to output directory.

Is it possible to replace one of the assemblies at runtime, if it exist a new version of that assembly?

Best regards
Olof

Re: Replace assembly at runtime

David Ewen8-Nov-10 22:07

David Ewen

8-Nov-10 22:07

Short answer: No

Shortish answer: If you get to it early enough (before any types (or types that reference the types) are instantiated that reference the dlls) you can overwrite them.

Long answer: If you need more than the above gives you like being able to swap the types after they have been used you need to create a seperate AppDomain and load the dlls into that. If they get updated you can destroy the AppDomain and create a new one with the new dlls.

It all depends on what you are trying to achieve.

Re: Replace assembly at runtime

John Gathogo8-Nov-10 22:08

John Gathogo

8-Nov-10 22:08

One way would be to load the assemblies using Reflection. That way, if an assembly changes periodically, you will get the latest

Re: Replace assembly at runtime

marca2928-Nov-10 22:18

marca292

8-Nov-10 22:18

Hi, a lot of the types declared in the assembly I want to update at runtime are used both in this assembly and in other assemblies. And since a lot of people are working in the project at the same time it's not easy to make a bigger reorganization of the source files.

Re: Replace assembly at runtime

Pete O'Hanlon9-Nov-10 1:54

Pete O'Hanlon

9-Nov-10 1:54

The traditional way to approach this would be to use Dependency Injection to inject the appropriate DLL at runtime. The best way to do this is to not hardcode your type references, but rather you would work against interfaces which the concrete classes would implement. There are many benefits to doing this such as creating more testable objects, improving the loose cohesion of the system, etc.

I have CDO, it's OCD with the letters in the right order; just as they ruddy well should be

Forgive your enemies - it messes with their heads

My blog | My articles | MoXAML PowerToys | Onyx

How can I access my Mainwindow-controls from a thread?

Erik8-Nov-10 20:45

Erik

8-Nov-10 20:45

Hi,

I am currently writing a gui-application, which does some processing in a thread. I pass a reference to my mainwindow to the thread, in order to make the thread set some text inside the mainwindow. However, when I try to access any control in my mainwindow from my thread, I get:

"An unhandled exception of type 'System.InvalidOperationException' occurred in WindowsBase.dll"

Simple question: what is the best way to access mainwindo-gui elements from a thread?

This is what my code looks like:

public MainWindow()
     {
         InitializeComponent();
         _ProcessHelperThread = new System.Threading.Thread(ProcessHelperThread);
         _ProcessHelperThread.Start();
     }

     void ProcessHelperThread()
     {
         Processes.Init(this); //this is a reference to my mainwindow
         //run the processes defined in Startup configuration
         Processes.Startup();
     }

Inside the thread (i.e. in my Processes-object), my app crashes when I try something like this:

public int Init(MainWindow window)
   {
       window.textBlock1.Text = Waittext; //Exception
   }

What is a better way to do this?

Re: How can I access my Mainwindow-controls from a thread?

David Ewen8-Nov-10 21:06

David Ewen

8-Nov-10 21:06

I would have expected a cross thread exception rather than the one you got but the correct way to update gui elements from another thread is the call Invoke on the control. This is for WinForms not WPF.

public Form1()
{
	InitializeComponent();

	Thread workerThread = new Thread(WorkerThread);
	workerThread.Start();
}

private void WorkerThread()
{
	UpdateWindowText(this);
}

private void UpdateWindowText(Form1 form)
{
	form.Invoke((Action) (() => form.Text = "test"));
}

Re: How can I access my Mainwindow-controls from a thread?

David Ewen8-Nov-10 21:14

David Ewen

8-Nov-10 21:14

As a follow up this is how it is done in WPF.

public MainWindow()
{
	InitializeComponent();

	Thread workerThread = new Thread(WorkerThread);
	workerThread.Start();
}

private void WorkerThread()
{
	UpdateWindowText(this);
}

private void UpdateWindowText(Window window)
{
	window.Dispatcher.Invoke((Action) (() => window.Title = "test"));
}

Re: How can I access my Mainwindow-controls from a thread?

Erik8-Nov-10 21:50

Erik

8-Nov-10 21:50

Thanks alot, this solution works perfectly!

Datagridview

yesu prakash8-Nov-10 20:41

yesu prakash

8-Nov-10 20:41

hi,
How to add a blank row in the last index when click on the datagridview. When we type any character in any cell a new blank row is generated by default, likewise i need to generate in any click. AllowUsertoaddrow is set to true.

Thankyou

Re: Datagridview

David Ewen8-Nov-10 20:50

David Ewen

8-Nov-10 20:50

This will create a new row when the current new row gets clicked. I could see how this may be annoying for users though but I will assume you have your reasons.

public Form1()
{
	InitializeComponent();

	dataGridView1.CellClick += new DataGridViewCellEventHandler(dataGridView1_CellClick);
}

private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
{
	DataGridView dataGridView = sender as DataGridView;
	if(dataGridView.Rows[e.RowIndex].IsNewRow)
	{
		int newRowIndex = dataGridView.Rows.Add();
		dataGridView.CurrentCell = dataGridView.Rows[newRowIndex].Cells[e.ColumnIndex];
	}
}

Socket and Thread Question

jason_mf8-Nov-10 18:45

jason_mf

8-Nov-10 18:45

I have a Server, and several Client.

a meth receive data from client. then store these data in global variable temporary then deal.

e.g.
public void ReceiveMethod(object data)
{
//maybe Multiple client at the same time.
DealData(data);
}

public void DealData(object data)
{
//some values will store in global variable temporary.
//because Multiple client Send data,so the global variable's value is mistake. like mult-Thread without synchrony or lock.
//if this is Multiple Thread deal, I understand it.
//but I dont execute thread or asynchronization obvious.
//is Mult-Thread here?
}

Re: Socket and Thread Question

Rajesh Anuhya8-Nov-10 18:55

Rajesh Anuhya

8-Nov-10 18:55

What is your Question??, I am not able to Understand your Problem....

Confused | :confused:

Rajesh B --> A Poor Workman Blames His Tools <--

Re: Socket and Thread Question

jason_mf8-Nov-10 18:58

jason_mf

8-Nov-10 18:58

Is the DealData Method a assistant Thread?

MultiThreading

RoboAlex8-Nov-10 17:26

RoboAlex

8-Nov-10 17:26

Dear All

What are the main reasons to freeze a multithreaded application? Is it due to thread asynchronous or thread dead lock? Could any one suggest me a good approach to debug multithreaded application?

Thanks
Regards
Alex

Re: MultiThreading

Luc Pattyn8-Nov-10 17:31

Luc Pattyn

8-Nov-10 17:31

I see no reasons to freeze an app, multi-threaded or not. There may be causes why it is freezing nevertheless.
First thing to look for: are there one or more busy loops (is CPU load very high, say close to 100%, or maybe close to 50% on a dual-core, etc)? or is everything really idle (CPU load nearly zero)?

Debugging advice:
1. don't create a huge app with lots of problems and only then start fixing the problems; start small and make sure it is correct from the start.
2. improve observability by inserting logging statements, where each line shows DateTime.Now (up to ss.fff) and the thread ID.

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

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Re: MultiThreading

Rajesh Anuhya8-Nov-10 18:57

Rajesh Anuhya

8-Nov-10 18:57

Vote 5: for this statement

don't create a huge app with lots of problems and only then start fixing the problems; start small and make sure it is correct from the start.

Good Answer Rose | [Rose]

Rajesh B --> A Poor Workman Blames His Tools <--

Re: MultiThreading

David Skelly8-Nov-10 22:27

David Skelly

8-Nov-10 22:27

Luc's advice is good. If you are still struggling, you could try taking a thread dump or memory dump when the application appears frozen and then you should be able to see what the different threads are doing.

There are a few tools that can help with this:

ADPlus[^]

Managed Stack Explorer[^]

Although Managed Stack Explorer is listed as a .NET 2 app, as far as I am aware it works with 3.0 and 3.5 also.

Re: MultiThreading

Luc Pattyn9-Nov-10 1:37

Luc Pattyn

9-Nov-10 1:37

I forgot to mention one popular way to cause a random freeze: invalid cross-thread GUI operations (either in .NET 1.x, or by setting Control.CheckForIllegalCrossThreadCalls false); when in doubt, read this article[^].

Smile | :)

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Return all form controls to default state

kruegs358-Nov-10 17:20

kruegs35

8-Nov-10 17:20

I have a form with a lot of textboxes, etc... that are set to read-only or disabled. I have a "edit" button that allows the user to edit values on the form. I would like to add a "cancel" button that returns all of the controls back to their default state. I would like to know if there is a simple function that can be called similar to the initial load of the form. If not, I suppose I have to write a lot of code to change all of the controls back, one by one.

Re: Return all form controls to default state

Luc Pattyn8-Nov-10 17:26

Luc Pattyn

8-Nov-10 17:26

Two easy ways would be:

1. create a new Form
2. remove all top-level controls (this.Controls.Clear) and call InitComponent() again.

Both are more costly than is necessary.

Approach #3: You could enumerate all controls and reset them; in general this takes a recursive approach as TextBoxes could sit in Panels in SplitContainers, etc.

All these approaches have one thing in common: they are Form-agnostic, they don't really care exactly what Controls are present.

Approach #4 (More advanced): if your app is data-driven, chances are your Form represents one data object which has a class and probably also a DataRow, corresponding to a row in some DB table. If so, you are already using data binding, and could bind with a new (i.e. empty) object to clear everything.

FWIW a final remark: if your Form holds that many Controls that you see clearing them as a problem, then your users will probably not like it either for how it looks and how uneasy it is to use.

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

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Can you gain administrator permission in .NET program?

John Kenedy S.Kom8-Nov-10 16:08

John Kenedy S.Kom

8-Nov-10 16:08

I have noticed that why anti virus, and other programs can gain administrator access when the app started when computer starts?
And why not .net created application? If I set to request administrator level in exe manifest, it will prompt user for permission, and it is very annoying since this application is automatically started at computer startup. How do I gain administrator permission (or at least the user login permission) without asking for password?
Why native exe can do it and why not .net exe?
Should we all move to C++ instead of supporting C#?

Any idea? or complains?

Re: Can you gain administrator permission in .NET program?

Jacob D Dixon8-Nov-10 17:44

Jacob D Dixon

8-Nov-10 17:44

http://www.developerfusion.com/code/7987/making-a-net-app-run-on-vista-with-administrator-priviledges/[^]

Check that out.

<requestedExecutionLevel level="asInvoker" uiAccess="false" />

Should run under the the user that started the application.

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.