How to do something similar to C# Invoke() in Delphi? - delphi

Question

I'm writing a project with Delphi. I need to do something to do the function that the Invoke method in C# does. I saw the Synchronize() method do this somewhere, but I don't know exactly how to write it. How can I do it ?
C# code:
private void ListenerOnDataTransmit(DataTransmitEventArgs e)
{
transmittedMsg = BitConverter.ToString(e.TransmittedBytes, 0, e.TransmittedBytes.Length);
//I want to write here
try { Invoke(new EventHandler(UpdateTransmittedMessagesListView)); }
catch { }
}
// UpdateTransmittedMessagesListView
public void UpdateTransmittedMessagesListView(object sender, EventArgs e)
{
ListViewItem item = new ListViewItem(DateTime.Now.ToLongTimeString());
item.SubItems.Add(transmittedMsg);
lvTransmittedMessages.Items.Insert(0, item);
if (lvTransmittedMessages.Items.Count > 100)
lvTransmittedMessages.Items.Clear();
}
public MainForm()
{
InitializeComponent();
plistener.OnDataTransmit += new DataTransmitEventHandler(ListenerOnDataTransmit);
}
The codes are like this, I want to do the operations on the Invoke line in the first function.

Answer 1

In C#, the Invoke() method "Executes a delegate on the thread that owns the control's underlying window handle".
In Delphi, UI controls are (supposed to be) owned by the main UI thread. You can use the TThread.Synchronize() or TThread.Queue() method to execute code from a worker thread in the context of the main UI thread, eg:
type
TWorkerThread = class(TThread)
private
FData: string;
procedure DoUpdate;
protected
procedure Execute; override;
end;
procedure TWorkerThread.Execute;
begin
...
FData := ...;
Synchronize(DoUpdate);
...
end;
procedure TWorkerThread.DoUpdate;
var
Item: TListItem;
begin
Item := MyForm.lvTransmittedMessages.Items.Add;
Item.Caption := DateTimeToStr(Now);
Item.SubItems.Add(FData);
if MyForm.lvTransmittedMessages.Items.Count > 100 then
MyForm.lvTransmittedMessages.Items.Clear;
end;
Alternatively:
procedure SomeWorkerThreadProc;
var
s: string;
begin
s := ...;
TThread.Synchronize(nil,
procedure
var
Item: TListItem;
begin
Item := MyForm.lvTransmittedMessages.Items.Add;
Item.Caption := DateTimeToStr(Now);
Item.SubItems.Add(s);
if MyForm.lvTransmittedMessages.Items.Count > 100 then
MyForm.lvTransmittedMessages.Items.Clear;
end
);
end;