UIButton click event getting called multiple times

问题:

I have a custom UITableViewCell which has an UIButton in it. When the button is clicked the click event is getting called multiple times. Here is the code what i am using.

CustomCell.cs

public static CustomCell Create ()
{
    return ( CustomCell ) Nib.Instantiate ( null , null ) [0];
}

internal void BindData()
{
    //some code

    btnSave.TouchUpInside+= (object sender, EventArgs e) => 
    {
        Console.WriteLine("button clicked");
    };
}

TableSource.cs

public override UITableViewCell GetCell (UITableView tableView,NSIndexPath indexPath)
{
    CustomCell cell = tableView.DequeueReusableCell ( CustomCell.Key ) as CustomCell ??  CustomCell.Create ();
    cell.BindData ();
    return cell;
}

Any idea why is this happening? am i reusing the cells properly?

Thank you.

回答1:

I believe you should not call cell.BindData() every time, only when you create a new cell. Otherwise you will be running it every time you re-use your cell.

separate the bind data stuff... pull out the button touch

internal void BindData()
{
    //some code
}

and then put the button stuff in here.

var cell = tableView.DequeueReusableCell(CustomCell.Key) as CustomCell;

if (cell == null)
{
    cell = CustomCell.Create ()
    cell.btnSave.TouchUpInside+= (object sender, EventArgs e) => 
    {
        Console.WriteLine("button clicked");
    };
}

cell.BindData ();

回答2:

Its late reply I came across same problem and solved as follow,might be useful for others:

cell.tnSave.TouchUpInside -= handler; 
cell.tnSave.TouchUpInside += handler;

This will prevent from adding same handler to button's touchupinsider event multiple time. handler can be defined as :

void handler(Object sender, EventArgs args)
        {
            Console.WriteLine("button clicked");
        }