UIResponder.CanPerform(Selector, NSObject) Method

Reference

Definition

Namespace:: UIKit

Assembly:: Xamarin.iOS.dll

Important

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Determines if this UIResponder can perform the specified action. Typically used to probe for editing commands.

[Foundation.Export("canPerformAction:withSender:")]
public virtual bool CanPerform (ObjCRuntime.Selector action, Foundation.NSObject withSender);

abstract member CanPerform : ObjCRuntime.Selector * Foundation.NSObject -> bool
override this.CanPerform : ObjCRuntime.Selector * Foundation.NSObject -> bool

Parameters

action: Selector

The selector that represents the action that is being probed. For editing operations, these selectors are "copy:", "cut:", "delete:", "paste:", "select:", "selectAll:", "toggleBoldface:", "toggleItalics:", "toggleUnderline:".

withSender: NSObject

The object invoking this method.

This parameter can be null.

Returns

Boolean

True if the specified action can be performed with the specified sender.

Attributes: ExportAttribute

Remarks

This method should return true if the action specified by the selector can be performed by the object.

//
// Selectable label: a label that shows the "Copy" menu when the user
// long presses
//
public class SelectableLabel : UILabel {

public SelectableLabel (RectangleF rect) : base (rect)
{
UserInteractionEnabled = true;
var gesture = new UILongPressGestureRecognizer (LongPress);
AddGestureRecognizer (gesture);
}

void LongPress (UILongPressGestureRecognizer r)
{
var location = r.LocationInView (r.View);
var menu = UIMenuController.SharedMenuController;

r.View.BecomeFirstResponder ();

menu.SetTargetRect (r.View.Frame, r.View);
menu.SetMenuVisible (true, true);
}


public override bool CanBecomeFirstResponder { 
get { return true; } 
}

Selector copyAction = new Selector ("copy");

public override bool CanPerform (Selector action, NSObject withSender)
{
if (action == copyAction);
return true;
return false;
}

public override void Copy (NSObject sender)
{
UIPasteboard.General.String = this.Text;
}
}

Applies to

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