C#•2y ago

❔ Update Form in a new Thread!

I created a form with a datagridview. Now I want to run a powershell command in a new thread and in this new thread I want to add the data from the powershell command in the datagridview. With normal threads I get an error which says that I can not call the datagridview from the main thread is there another way doing that?

15 Replies

jcotton42•2y ago

you cannot touch UI controls outside of the UI thread to post code to the UI thread, you can use the Invoke method on any control from your Form

jcotton42•2y ago

https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.control.invoke?view=windowsdesktop-7.0

Control.Invoke Method (System.Windows.Forms)

Executes a delegate on the thread that owns the control's underlying window handle.

ippoOP•2y ago

@jcotton42 I used Invoke with Action and with delegate but nothing works I mean I get the results at the same time and not one after the other, but it is still locking the UI thread

jcotton42•2y ago

wdym "locking the UI thread"? as in the app is not responsive during the operation? how are you running the powershell?

ippoOP•2y ago

foreach (PSObject result in myCommand.Invoke()) {
    dataGridView.Rows.Add(
       result.Members["Name"].Value,
       result.Members["Count"].Value,
    );
}

foreach (PSObject result in myCommand.Invoke()) {
    dataGridView.Rows.Add(
       result.Members["Name"].Value,
       result.Members["Count"].Value,
    );
}

as in the app is not responsive during the operation?

yes! this is what I tried:

dataGridView1.Invoke((MethodInvoker)delegate {
    // the foreach code with the ps invoke()
});

dataGridView1.Invoke((MethodInvoker)delegate {
    // the foreach code with the ps invoke()
});

dataGridView1.Invoke(new Action(() =>  {
    // the foreach code
});

dataGridView1.Invoke(new Action(() =>  {
    // the foreach code
});

dataGridView1.Invoke(new Action(() =>  {
    // the foreach with invoke()
});

dataGridView1.Invoke(new Action(() =>  {
    // the foreach with invoke()
});

Thread t = new Thread(() => {
    dataGridView1.Invoke(new Action(() =>  {
        // the foreach with invoke()
    });
});

t.Start()

Thread t = new Thread(() => {
    dataGridView1.Invoke(new Action(() =>  {
        // the foreach with invoke()
    });
});

t.Start()

all of these solutions are locking

jcotton42•2y ago

sorry, I more meant how you are invoking the powershell code? the bit that would actually be typing up the UI

ippoOP•2y ago

not sure what you mean, but maybe you mean this?

PowerShell ps = PowerShell.Create();
ps.AddScript(myPsScript);

foreach (PSObject result in ps.Invoke()) {
    dataGridView.Rows.Add(
       result.Members["Name"].Value,
       result.Members["Count"].Value,
    );
}

PowerShell ps = PowerShell.Create();
ps.AddScript(myPsScript);

foreach (PSObject result in ps.Invoke()) {
    dataGridView.Rows.Add(
       result.Members["Name"].Value,
       result.Members["Count"].Value,
    );
}