MonoTouch.Dialog:如何设置 EntryElement 的字符数限制 [英] MonoTouch.Dialog: How to set limit of number of characters for EntryElement

问题描述

我找不到如何限制 EntryElement

推荐答案

我也更喜欢继承和事件 :-) 试试这个:

I prefer inheritance and events too :-) Try this:

class MyEntryElement : EntryElement {

    public MyEntryElement (string c, string p, string v) : base (c, p, v)
    {
        MaxLength = -1;
    }

    public int MaxLength { get; set; }

    static NSString cellKey = new NSString ("MyEntryElement");      
    protected override NSString CellKey { 
        get { return cellKey; }
    }

    protected override UITextField CreateTextField (RectangleF frame)
    {
        UITextField tf = base.CreateTextField (frame);
        tf.ShouldChangeCharacters += delegate (UITextField textField, NSRange range, string replacementString) {
            if (MaxLength == -1)
                return true;

            return textField.Text.Length + replacementString.Length - range.Length <= MaxLength;
        };
        return tf;
    }
}

但也在这里阅读 Miguel 的警告(编辑到我的帖子):MonoTouch.对话框:为 EntryElement 设置条目对齐

but also read Miguel's warning (edit to my post) here: MonoTouch.Dialog: Setting Entry Alignment for EntryElement

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