Selector in UITableViewCell in Xamarin

Question

I need the UIMenuItem to call a method inside the UITableViewCell. Something similar is possible in swift as explained here: https://stackoverflow.com/a/31358474/202179 .

At the moment I am only able to call the method inside the UIViewController from the UIMenuItem if I add an Export attribute to the method.

There is some trick in the export of this method in the cell, but I have failed to find it till now. I would expect this code to work, but it doesn't:

[Register("CustomCell")]
public class CustomCell : UITableViewCell
{
    public CustomCell(IntPtr intPtr) : base(intPtr)
    {
        var menuItem = new UIMenuItem("Menu Item", new ObjCRuntime.Selector("CustomCell.SeekSelectedText"));
        UIMenuController.SharedMenuController.MenuItems = new UIMenuItem[] { menuItem };
        UIMenuController.SharedMenuController.Update();
    }

    [Export("SeekSelectedText")]
    void SeekSelectedText()
    {
        //do something
    }
}

As said just quoting a different selector inside the UIViewController works, so the problem is that this selector doesn't appear to be recognized whatever I try.

Answer 1

Here is my test and the custom UIMenuItem works fine.

First, define a custom cell class which inherits UITableViewCell

class MyCell: UITableViewCell
{
    public MyCell(UITableViewCellStyle style, string reuseIdentifier):base(style, reuseIdentifier)
    {

    }

    [Export("custom")]
    void Custom()
    {
        //do something
        Console.WriteLine("custom pop up");
    }

    public override bool CanPerform(Selector action, NSObject withSender)
    {
        if (action == new Selector("custom"))
            return true;
        else
            return false;
    }
}

Second, set the source of your UITableView

class MyTableViewSource : UITableViewSource
{
    int i = 0;
    // create custom cell
    public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
    {
        string cellStr = "cell";
        MyCell cell = (MyCell)tableView.DequeueReusableCell(cellStr);
        if (cell == null)
        {
            cell = new MyCell(UITableViewCellStyle.Subtitle, cellStr);
            cell.TextLabel.Text = $"User Name {i}";
            cell.DetailTextLabel.Text = $"details here... {i++}";
        }
        return cell;
    }
    public override nint RowsInSection(UITableView tableview, nint section)
    {
        return 10;
    }
}

Then override the realted methods(e.g., ShouldShowMenu, CanPerformAction).

class MyTableViewDelegate : UITableViewDelegate
{
    public override bool ShouldShowMenu(UITableView tableView, NSIndexPath rowAtindexPath)
    {
        return true;
    }

    public override bool CanPerformAction(UITableView tableView, Selector action, NSIndexPath indexPath, NSObject sender)
    {
        return true;
    }

    public override void PerformAction(UITableView tableView, Selector action, NSIndexPath indexPath, NSObject sender)
    {

    }

    public override bool ShouldHighlightRow(UITableView tableView, NSIndexPath rowIndexPath)
    {
        return true;
    }
}

Last, don't foget to add custom MenuItem to your UITableViewCell.

UIMenuController.SharedMenuController.MenuItems = new UIMenuItem[] {
    new UIMenuItem ("Custom", new Selector ("custom"))
};

Since UICollectionView has similar functions to UITableVIew, you can directly refer to the sample SimpleCollectionView.