ContentView 中的按钮导致 MonoTouch 运行时崩溃.Monotouch 4.0 中的错误?

问题描述

我的应用程序在 MT 3.0 中运行良好.现在当我升级时.当按钮位于 ContentView 中时，我看到错误.单击按钮时会发生崩溃.代码:

My application worked fine in MT 3.0. Now when I upgraded. I am seeing errors when a button is in a ContentView. Crashes happen when the button is clicked. Code:

public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPa
    float width = tableView.Bounds.Width - 70;

    var cell = tableView.DequeueReusableCell(kCellIdentifier);
    //if (cell == null)
    //{
    cell = new UITableViewCell(UITableViewCellStyle.Subtitle, kCellIdentifier);
    // }

    var behavior = tvc.behaviors.ElementAt(indexPath.Row);
    cell.TextLabel.Text = behavior.Name;
    cell.TextLabel.Font = UIFont.BoldSystemFontOfSize(22f);
    cell.DetailTextLabel.Text = behavior.Definition;
    var view = UIButton.FromType(UIButtonType.Custom);
    view.Tag = indexPath.Row;
    view.SetImage(UIImage.FromBundle("Images/plus.png"), UIControlState.Normal);
    view.Frame = new RectangleF(width - 50, 10, 50, 50);

    view.TouchUpInside += IncrementBehavior;

    var label = new UILabel(new RectangleF(width - 80, 10, 50, 50));
    label.Text = behavior.CurrentCount.ToString();
    label.BackgroundColor = UIColor.Clear;
    label.Font = UIFont.BoldSystemFontOfSize(24f);
    cell.ContentView.AddSubview(view);
    cell.ContentView.AddSubview(label);
    //cell.BackgroundColor = UIColor.Clear;)

    return cell;
}

void IncrementBehavior(object sender, EventArgs e) {
    var button = (UIButton)sender;
    var tag = button.Tag;
    var behavior = tvc.behaviors[tag];

    var indexpath = NSIndexPath.FromRowSection(tag, 0);
    var newBehavior = Repository.GetBehavior(behavior.Id);
    newBehavior.CurrentCount++;
    Repository.Update(newBehavior);
    tvc.behaviors[tag] = newBehavior;


    tvc.TableView.ReloadRows(new[] { indexpath }, UITableViewRowAnimation.None);

}

我交替收到这些错误:

Name: NSInvalidArgumentException Reason: -[__NSCFSet BridgeSelector]: unrecognized selector sent to instance 0x5c3c570

和

No constructor found for MonoTouch.UIKit.UIControlEventProxy::.ctor(System.IntPtr)

推荐答案

不确定是否是这个问题，但是当我升级到 4.0 时，我也遇到了一些随机崩溃.结果证明 4.0 GC 更具侵略性，而且我之前逃避的事情不再是 kosher 了.

Not sure if this is the problem, but when I upgraded to 4.0, I also got some random crashes. It turned out that the 4.0 GC is more aggressive, and that things I was previously getting away with were no longer kosher.

特别是，如果我有一个分配给按钮的事件处理程序，我需要确保按钮是在类级别声明的.如果它是在方法中本地声明的，GC 会在它超出范围时清除引用，然后当事件处理程序尝试触发时，它的引用不再存在.

In particular, if I had a event handler assigned to a button, I needed to be sure the button was declared at the class level. If it was declared locally in the method, the GC would purge the reference when it went out of scope, and then later when the event handler tried to fire, it's reference was no longer there.

所以尝试将按钮的声明移到方法之外.

So try moving the declaration of your button outside of your method.

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