Cast to a control using the control name as a stri

问题:

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Syntax help - Variable as object name [duplicate] (1 answer)

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Closed 6 years ago.

I have several textfields (and labels) in my XIB and at some point in my application I build dynamicaly a string which contains a control name (i.e. one of the textfields). How can I refer to the actual textfield using the string I created that holds the name of the textfield.

For example, I have txt1 , txt2, txt3, txt4 as UITextFields and i have a string (str) that contains one of the fields above names (str ="txt3") then i want to change the content of the uitextfield txt3 since str have "txt3" at this point.

How do I cast from the string to the actual control?

回答1:

If the UITextFields all have a backing property then you can use KVC to get a reference to the control and then you just use it as normal.

NSString *str = @"txt1";
UITextField *myTextField = [self valueForKey:str];
myTextField.text = @"what ever you want to update to";

Side note

Although you have not mentioned the source of str @JefferyThomas raises a very valid point about not trusting use input that has not been validated.