Winforms Programming

1)How can we stop the tab flow from keyboard Tab key?

 Using TabStop=False;
How can we pass one form data to another in winforms?

If you want to display child form data into parent form ,  declaring static variable in child forms.

2)What is difference between performLayout() and ResumeLayout(false);

How can we restrcit copy paste option textbox in winforms?

txtProgSigTimeLimit.ShortcutsEnabled = false;

How can we restict textbox from entering Letters, Whitespaces,Punctuation,Symbols?

if ((Char.IsWhiteSpace((char)e.KeyChar)) || (Char.IsLetter((char)e.KeyChar)) || (Char.IsPunctuation((char)e.KeyChar)) || (Char.IsSymbol((char)e.KeyChar)))
   {
      e.Handled = true;
      return;
   }