How to simulate the click of button in c# code in wpf,performclick met

Use RaiseEvent(from System.Windows(PresentationCore.dll)) or Automation Peer (from System.Windows.Automation.Peers (PresentationFramework.dll)), i recommend you to use RaiseEvent. WPF takes a slightly different approach than WinForms here. WPF don't have PerformClick().

// using raise event
Button someButton = new Button();
someButton.RaiseEvent(new RoutedEventArgs(Button.ClickEvent, someButton));
// using Automation Peer
ButtonAutomationPeer peer = new ButtonAutomationPeer( someButton );
IInvokeProvider invokeProv = peer.GetPattern( PatternInterface.Invoke ) as IInvokeProvider;
invokeProv.Invoke();