以编程方式设置其字符串值时，使NSTextField更新其绑定值 [英] Make NSTextField update its bound value when setting its string value programmatically

问题描述

我有一个NSTextField绑定到用户默认设置中的键。当我按Enter或离开该字段时，绑定值已正确更新（我有一个观察者）。但是，当我以编程方式设置文本字段的值时，绑定值不会更新。但是，文本字段显示了我设置的新字符串：

I have an NSTextField bound to a key in the user defaults. When I press enter or leave the field the bound value is properly updated (I have an observer for it). However when I programmatically set the value of the text field the bound value is not updated. The text field however shows the new string I set with:

stockField1.stringValue = [sender representedObject];

（由菜单项处理程序设置）。

(it's set from a menu item handler). Is it necessary to send an additional message to the text field or how else can I make this work?

推荐答案

手动触发密钥，是否有必要向文本字段发送其他消息？值绑定是这样的：

Manually triggering key-value binding goes like this:

- (void)symbolSelected: (id)sender
{
    NSTextField *field;
    switch ([sender tag]) {
        case 0:
            field = stockField1;
            break;
        case 1:
            field = stockField2;
            break;
        case 2:
            field = stockField3;
            break;
    }

    field.stringValue = [sender representedObject];
    NSDictionary *bindingInfo = [field infoForBinding: NSValueBinding];
    [[bindingInfo valueForKey: NSObservedObjectKey] setValue: field.stringValue
                                                  forKeyPath: [bindingInfo valueForKey: NSObservedKeyPathKey]];
}

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