C# – WPF with Windows Forms – STAThread

cstawinformswpf

I am a newbie to WPF and have a couple of questions about WPF and Windows Forms integration.

I have an existing Visual C# Windows Forms application. I would like to integrate it with a WPF window, that can be shown on a button click. This was not possible as WPF expects the calling thread to be a STAThread and by default WinForm assumes that the thread is an MTAThread. I tried spawning a new thread with an apartment state of STAThread for calling the WPF UI but that did not work. I tried using the Dispatcher.BeginInvoke method and Background Worker as well, but none of them resolved the issue.

1) Can we make a call to WPF window/control without marking the Main as an STAThread? If it is possible, Can anyone please point me to a proper direction?
2) If the only way to accomplish this is by making the Main Thread an STAThread, will there be any impact to the general performance/responsiveness of the application.

Thanks in advance.

Best Answer

I think the simplest solution is to make your WinForms thread execute in an STA. There is nothing wrong with having an STA thread winforms app (it is in fact often the default).

You can fix this by adding the following line to the main method of your program:

[STAThreadAttribute]
static void Main(string[] args)

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C# – Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

As per Prerak K's update comment (since deleted):

I guess I have not presented the question properly.

Situation is this: I want to load data into a global variable based on the value of a control. I don't want to change the value of a control from the child thread. I'm not going to do it ever from a child thread.

So only accessing the value so that corresponding data can be fetched from the database.

The solution you want then should look like:

UserContrl1_LOadDataMethod()
{
    string name = "";
    if(textbox1.InvokeRequired)
    {
        textbox1.Invoke(new MethodInvoker(delegate { name = textbox1.text; }));
    }
    if(name == "MyName")
    {
        // do whatever
    }
}

Do your serious processing in the separate thread before you attempt to switch back to the control's thread. For example:

UserContrl1_LOadDataMethod()
{
    if(textbox1.text=="MyName") //<<======Now it wont give exception**
    {
        //Load data correspondin to "MyName"
        //Populate a globale variable List<string> which will be
        //bound to grid at some later stage
        if(InvokeRequired)
        {
            // after we've done all the processing, 
            this.Invoke(new MethodInvoker(delegate {
                // load the control with the appropriate data
            }));
            return;
        }
    }
}

C# – How to save application settings in a Windows Forms application

If you work with Visual Studio then it is pretty easy to get persistable settings. Right click on the project in Solution Explorer and choose Properties. Select the Settings tab and click on the hyperlink if settings doesn't exist.

Use the Settings tab to create application settings. Visual Studio creates the files Settings.settings and Settings.Designer.settings that contain the singleton class Settings inherited from ApplicationSettingsBase. You can access this class from your code to read/write application settings:

Properties.Settings.Default["SomeProperty"] = "Some Value";
Properties.Settings.Default.Save(); // Saves settings in application configuration file

This technique is applicable both for console, Windows Forms, and other project types.

Note that you need to set the scope property of your settings. If you select Application scope then Settings.Default.<your property> will be read-only.

Reference: How To: Write User Settings at Run Time with C# - Microsoft Docs

Best Answer

Related Solutions

C# – Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

C# – How to save application settings in a Windows Forms application

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