how to use Invoke method in a file of extensions/methods?

Question

Well, I'm writing a file of extensions/method useful to strings,label,linklabels,class etc.

but, I have a problem. I have an showMessage() method that change the Text of label, works fine. But I decide to do that works with thread execution, then I do this:

namespace LabelExtensions
{
    public static class LabelExtensionsClass
    {        
        private delegate void UpdateState();

        public static void ShowMessage(this Label label, string text)
        {
            if (label.InvokeRequired)
            {
                label.Invoke((UpdateState)delegate
                {
                    label.Text = text;
                });
            }
            else
            {
                  label.Text = text;
            }
        }
}
}

sorry, it was a typo. I typed this code on forum. the error continue.

according the documentation,to use the Invoke method need to imports:

Namespace: System.Windows.Forms

Assembly: System.Windows.Forms (in System.Windows.Forms.dll)

then I did:

using System.Windows.Forms;

but this returns same error:

The name 'Invoke' does not exist in the current context

how I fix this?

Thanks in advance.

Answer 1

Why not just do this:

label.BeginInvoke( (Action) (() => label.Text = text));

There is no need to create your own delegate. Just use the built-in Action delegate. You should probably create your extension method for the base Control class instead of the Label class. It'll be more reusable.

Answer 2

Change

Invoke((UpdateState)delegate …

to

label.Invoke((UpdateState)delegate …